What are the Common steel Varieties, Properties and Applications?

The success of your custom machined part often comes down to one crucial decision: choosing the right material. But with a vast universe of steel types available—from structural and tool steel to bearing and special grades—making the optimal choice can feel overwhelming. This guide will demystify the world of steel, breaking down the characteristics and applications of key categories so you can confidently select the perfect material to ensure your project's performance, longevity, and cost-efficiency.

(一) Structural steel

(一) Carbon structural steel

(1) Mechanical properties of carbon structural steel (see Table 3-1-4)

Table 3-1-4 Mechanical properties of carbon structural steel

(1)Tensile test and impact test

the name of a shop	grade	tension test													blow-test
		yield point σs/Mpa						Tensile strength σb/Mpa	Extension rate δ5 (%)						temperature （℃）	V-shaped impact absorption work (longitudinal) (J)
		Steel thickness (diameter)/mm							Steel thickness (diameter)/mm
		≤ 16	> 16 ~ 40	> 40 ~ 60	> 60 ~ 100	> 100 ~ 150	> 150		≤ 16	> 16 ~ 40	> 40 ~ 60	> 60 ~ 100	> 100 ~ 150	> 150
		least value							least value							least value
Q195	-	（195）	（185）	-	-	-	-	315 ~ 430	33	32	-	-	-	-	-	-
Q215	A	215	205	195	185	175	165	335 ~ 450	31	30	29	28	27	26	-	-
	B														20	27
Q235	A	235	225	215	205	195	185	375 ~ 500	26	25	24	23	22	21	-	-   27
	B														20
	C														0
	D														- 20
Q255	A	255	245	235	225	215	205	410 ~ 550	24	23	22	21	20	19	-	-
	B														20	27
Q275	-	275	265	255	245	235	225	490 ~ 630	20	19	18	17	16	15	-	-

(2)Cold bending test

the name of a shop	Sample Direction	180. Cold bending test B = 2a
		Steel thickness (diameter)/mm
		60	> 60 ~ 100	> 100 ~ 200
		Bend diameter d
Q195	release	0	-	-
	horizontal	0.5 α
Q215	release	0.5 α	1.5 α	2 α
	horizontal	α	2 α	2.5 α
Q235	release	α	2 α	2.5 α
	horizontal	1.5 α	2.5 α	3 α
Q255		2 α	3 α	3.5 α
Q275		3 α	4 α	4.5 α

Table 3-1-5 Characteristics and applications of carbon structural steel

the name of a shop	Main Features	Use examples
Q195	It has high plasticity, toughness and weldability, good pressure processing properties, but low strength	For manufacturing anchor bolts, plowshares, chimneys, roof panels, rivets, low-carbon steel wires, thin plates, welded pipes, tie rods, hooks, supports, and welded structures
Q215
Q235	It has good plasticity, toughness, weldability, cold stamping properties, and certain strength and good cold bending properties.	Extensively used in components and welded structures with general requirements, such as tension rods, connecting rods, pins, shafts, screws, nuts, washers, brackets, machine bases, building structures, and bridges.
Q255	It has good strength, plasticity and toughness, good welding properties and cold and hot pressure processing properties	Used to manufacture parts requiring low strength, such as bolts, keys, levers, shafts, tie rods, and various steel sections and steel plates for steel structures
Q275	It has high strength, good plasticity, good machinability, and certain weldability. Small parts can be hardened.	Used to manufacture parts requiring high strength, such as gears, shafts, sprockets, keys, bolts, nuts, steel for agricultural machinery, conveyor chains and chain links

(二）High quality carbon structural steel

(1) Mechanical properties of high quality carbon structural steel (see Table 3-1-6)

Table 3-1-6 Mechanical properties of high quality carbon structural steel

Characteristics and applications of carbon structural steel (see Table 3-1-6)

the name of a shop	Sample hair Bore size /mm	Recommended heat treatment/℃			Mechanical Performance					Hardness of steel delivery status HBS10/3000 ≤
		normalization	quench	tempering	σb   /Mpa	σs   /Mpa	δ5 （%）	ψ （%）	Aku2 /J
					≥					Unheat-treated steel	annealed steel
08F	25	930	-	-	295	175	35	60	-	131	-
10F	25	930	-	-	315	185	33	55	-	137	-
15F	25	920	-	-	355	205	29	55	-	143	-
08	25	930	-	-	325	195	33	60	-	131	-
10	25	930	-	-	335	205	31	55	-	137	-
15	25	920	-	-	375	225	27	55	-	143	-
20	25	910	-	-	410	245	25	55	-	156	-
25	25	900	870	600	450	275	23	50	71	170	-
30	25	880	860	600	490	295	21	50	63	179	-
35	25	870	850	600	530	315	20	45	55	197	-
40	25	860	840	600	570	335	19	45	47	217	187

45	25	850	840	600	600	355	16	40	39	229	197
50	25	830	830	600	630	375	14	40	31	241	207
55	25	820	820	600	645	380	13	35	-	255	217
60	25	810	-	-	675	400	12	35	-	255	229
65	25	810	-	-	695	410	10	30	-	255	229
70	25	790	-	-	715	420	9	30	-	269	229
75	sample	-	820	480	1080	880	7	30	-	285	241
80	sample	-	820	480	1080	930	6	30	-	285	241
85	sample	-	820	480	1130	980	6	30	-	302	255
15Mn	25	920	-	-	410	245	26	55	-	163	-
20Mn	25	910	-	-	450	275	24	50	-	197	-
25Mn	25	900	870	600	490	295	22	50	71	207	-
30Mn	25	880	860	600	540	315	20	45	63	217	187
35Mn	25	870	850	600	560	335	18	45	55	229	197
40Mn	25	860	840	600	590	355	17	45	47	229	207
45Mn	25	850	840	600	620	375	15	40	39	241	217
50Mn	25	830	830	600	645	390	13	40	31	255	217
60Mn	25	810	-	-	695	410	11	35	-	269	229
65Mn	25	830	-	-	735	430	9	30	-	285	229
70Nn	25	790	-	-	785	450	8	30	-	285	229

(2) Characteristics and applications of high quality carbon structural steel (Table 3-1-7)

Table 3-1-7 Characteristics and applications of high quality carbon structural steel

the name of a shop	Main Features	Use examples
08F	High-quality boiling steel with low strength and hardness, excellent plasticity. Good deep drawing and deep drawing properties, good cold workability and weldability. The components are highly prone to segregation and time sensitivity. Therefore, stress relief heat treatment or water toughening treatment can be used to prevent cold working fracture.	Easy to roll into thin plates, thin strips, cold-formed materials, and cold-drawn steel wires Used for stamping and rolling parts, various non-load-bearing coverings, carburized, nitrided, and cyanide-treated components, as well as the production of sleeves, molds, and supports.
08	Extremely soft low carbon steel, low strength and hardness, excellent plasticity and toughness, good cold workability, poor hardenability and hardening, slightly weaker aging sensitivity than 08F, not suitable for cutting, annealing, good magnetic conductivity	Suitable for rolling into thin plates, strips, cold-formed materials, cold drawing, cold stamping, welded parts, and surface-hardened parts.
10F 10	Low strength (slightly higher than 08 steel), excellent plasticity and toughness, good weldability, no temper brittleness. Easy to cold and hot forming, poor hardenability, good machinability after normalizing or cold working.	Cold rolling, cold stamping, cold heading, cold bending, hot rolling, hot extrusion, hot heading and other processes are suitable for forming parts with high toughness and low stress, such as friction plates, deep-drawn vessels, automobile bodies, and projectiles.
15F 15	The material's strength, hardness, and plasticity are comparable to those of 10F and 10 steel. To improve its machinability, it requires normalizing or water-hardening treatment to moderately increase hardness. It has low hardenability and poor hardenability, but excellent toughness and weldability.	Medium and small structural parts, screws, bolts, pull rods, lifting hooks, welded containers, etc., which are not subjected to much force and have simple shapes but require high toughness or good welding properties
20	The strength and hardness are slightly higher than 15F. The 15 steel has good plasticity and weldability, and good toughness after hot rolling or normalizing.	Manufacture of medium and small carbonitriding and carburizing components, forging parts such as lever shafts, gearbox shift forks, gears, heavy machinery tie rods, hooks and rings, etc.
25	It possesses a certain degree of strength and hardness, along with excellent plasticity and toughness. The material exhibits high weldability and cold plasticity, moderate machinability, but poor hardenability and hardening properties. After quenching and low-temperature tempering, it achieves good strength and toughness while avoiding temper brittleness.	Welded parts, hot-forged parts, and hot-stamped parts are carburized and used as wear-resistant parts
30	High strength and hardness, good plasticity and weldability, can be used after normalizing or tempered, suitable for hot forging and hot pressing. Good machinability.	Suitable for low-load components with minimal stress and temperatures below 150℃, such as lead screws, tie rods, shaft keys, gears, and bushings. The surface of carburized parts exhibits excellent wear resistance, making them ideal for wear-resistant applications.
35	The material has moderate strength, good plasticity, high cold plasticity, and acceptable weldability. It can be locally swaged and drawn in the cold state. It has low hardenability and can be used after normalizing or tempering.	Suitable for manufacturing small section parts, can withstand large loads, such as crankshaft, lever, connecting rod, hook ring, etc., various standard parts, fasteners
40	It has high strength, good cutting performance, moderate cold deformation ability, poor weldability, no temper brittleness, low hardenability, easy to produce water quench crack, mostly used in tempered or normalized state, the comprehensive performance of the two is similar, after surface hardening, it can be used to manufacture parts that bear large stress	Suitable for manufacturing crankshaft, drive shaft, piston rod, connecting rod, sprocket, gear, etc. When welding, it needs to be preheated first and slowly cooled after welding
45	The most commonly used medium-carbon tempered steel has good comprehensive mechanical properties and low hardenability, but is prone to cracking when water quenched. Small parts are suitable for tempering treatment, while large parts are suitable for normalizing treatment.	Primarily used for manufacturing high-strength components such as turbine blades, compressor pistons, shafts, gears, racks, and worms. For welded parts, ensure preheating before welding and stress relief annealing after welding.
50	This high-strength medium-carbon structural steel exhibits low cold deformation capability and moderate machinability. It demonstrates poor weldability, no temper brittleness, and limited hardenability, with a tendency to develop cracks during water quenching. Recommended usage: normalized, followed by quenching and tempering, or high-frequency surface hardening. Suitable for mechanical components requiring high wear resistance under conditions of minimal dynamic loads and impact forces.	Forging gears, tie rods, rolls, friction discs, machine tool spindles, engine crankshafts, agricultural machinery plowshares, heavy-duty shafts, and various shaft components, as well as less critical parts such as vibration-damping springs and spring washers.
55	It has high strength and hardness, but poor plasticity and toughness. Its machinability is moderate, and its weldability is poor. It has poor hardenability and is prone to cracking when water quenched. It is mostly used after normalizing or tempering treatment, and is suitable for manufacturing high strength, high elasticity, and high wear resistance parts.	Gears, connecting rods, rims, wheel flanges, locomotive wheel hoops, flat springs, hot rolled rollers, etc
60	It has high strength, high hardness and high elasticity. It has poor plasticity during cold deformation, medium cutting properties, poor weldability, poor hardenability, and easy to crack when water quenched. Therefore, it is normalized for large parts.	Roller, shaft, wheel hub, spring coil, vibration damping spring, clutch, steel wire rope
65	After appropriate heat treatment or cold working hardening, the material exhibits high strength and elasticity. However, it demonstrates poor weldability and is prone to cracking, making welding unsuitable. Additionally, it shows limited machinability, low cold deformation plasticity, and poor hardenability. Typically, oil quenching is employed, while large-section components may undergo water quenching with oil cooling or normalizing treatment. Notably, under identical configuration conditions, its fatigue strength can rival that of alloy spring steel.	Suitable for manufacturing flat or helical spring components with simple cross-sections and shapes, and low stress. Such as valve springs and spring rings. Also suitable for high-wear-resistant parts such as rolls, crankshafts, cams, and steel wire ropes.
70	The strength and elastic modulus are slightly higher than those of 65 steel, and other properties are similar to those of 65 steel	Spring, steel wire, steel band, wheel rim, etc
75 80	It has similar properties to 65 and 70 steels, but higher strength and slightly lower elasticity, and its hardenability is not high. It is usually used after quenching and tempering.	Spring plate, helical spring, anti-wear parts, low speed wheels, etc
85	High-carbon structural steel, which has the highest carbon content, has higher strength and hardness than other high-carbon steels, but slightly lower elasticity, and other properties are similar to 65,70,75,80 steels. The hardenability is still not high.	Railway vehicles, flat plate springs, round helical springs, steel wire steel strip, etc
15Mn	Low-carbon carburized steel with high manganese content (0.70% to 1.00% W Mn) exhibits superior strength, ductility, machinability, and hardenability compared to 15 steel. The reduced formation of soft spots during carburizing and quenching makes it ideal for carburizing and carburitizing treatments, delivering a surface with excellent wear resistance and a core with outstanding toughness. The material maintains good toughness after hot rolling or normalizing.	Gears, crankshafts, brackets, hinges, screws, nuts, riveted and welded structural components, sheet metal suitable for manufacturing oil tanks, and agricultural tools for cold regions such as cream containers.
20Mn	Its strength and hardenability are slightly higher than 15Mn steel, and other properties are similar to 15Mn steel	Essentially the same as 15Mn steel
25Mn	The performance is similar to 20Mn and 25 steel, and the strength is slightly higher	Similar to 20Mn and 25 steel
30Mn	Compared with 30 steel, it has higher strength and hardenability, good plasticity during cold deformation, medium weldability and good machinability. It has tendency of temper brittleness and overheating sensitivity during heat treatment.	Bolt, nut, screw, pull rod, lever, small shaft, brake gear
35Mn	It has higher strength and hardenability than 30Mn, moderate plasticity during cold deformation, good machinability, but poor weldability. It is recommended to use after tempering treatment.	Shaft, gear rod, bolt, nut, screw, etc., shaft, gear, etc.
40Mn	The hardenability is slightly higher than 40 steel. After heat treatment, the strength, hardness and toughness are slightly higher than 40 steel. The cold deformation plasticity is moderate, the cutting performance is good, the weldability is low, the overheating sensitivity and temper brittleness are present, and the water quenching is easy to crack.	Fatigue-resistant components, crankshafts, rollers, shafts, and connecting rods. Screws and nuts operating under high stress.
45Mn	Medium carbon quenched and tempered structural steel exhibits excellent comprehensive mechanical properties after treatment. It demonstrates superior hardenability, strength, and toughness compared to 45 steel, along with good machinability. However, it shows low cold deformation plasticity and poor weldability, with a tendency to develop temper brittleness.	Shaft, mandrel, spline shaft, automotive half shaft, universal joint shaft, crankshaft, connecting rod, brake lever, engagement rod, gear, clutch, bolt, nut, etc.
50Mn	The performance is similar to 50 steel, but its hardenability is higher, and the strength, hardness and elasticity are slightly higher than 50 steel after heat treatment. The weldability is poor, with overheating sensitivity and tendency to temper brittleness.	Designed for high-stress applications and wear-resistant components, such as gears, gear shafts, friction discs, mandrels, and flat springs.
60Mn	The strength, hardness, elasticity, and hardenability are slightly higher than those of 60 steel. The machinability of annealed state is good, but the cold deformation plasticity and weldability are poor. It has overheating sensitivity and tendency to backfire brittleness.	Large-sized helical springs, leaf springs, various round and flat springs, spring rings, spring sheets, cold-drawn steel wires, and springs
65Mn	It has higher strength, hardness, elasticity and hardenability than 65 steel, but has overheating sensitivity and tendency to backfire brittleness, and tends to form cracks when water quenched. The cutting performance in annealed state is acceptable, but the plasticity of cold deformation is low and the weldability is poor.	Medium load plate springs, spiral springs with diameters ranging from 7 to 20mm, along with spring washers and spring rings. These components exhibit exceptional wear resistance, including applications such as grinding machine spindles, spring collets, precision machine tool lead screws, plows, cutting tools, sleeve rings in screw roller bearings, and railway rails.
70Mn	The performance is similar to 70 steel, but the hardenability is slightly higher. The strength, hardness and elasticity are better than 70 steel after heat treatment. It has overheating sensitivity and tendency to temper brittleness, easy decarburization and tendency to form cracks when water quenching, poor cold plastic deformation ability and poor weldability.	Working parts subjected to high stress and wear, such as spring coils, spring washers, thrust rings, locking rings, and clutch discs.

（三）Low alloy high strength structural steel

(1) Mechanical properties of low alloy high strength structural steel (see Table 3-1-8)

Table 3-1-8 Mechanical properties of low alloy high strength structural steel

the name of a shop	grade	yield point σs/Mpa ≥				Tensile strength σb/Mpa	Extension rate δ5 (%) ≥	Impact absorption energy (longitudinal) Akv/J ≥
		Thickness (diameter, side length) /min
		≤ 16	> 16 ~ 35	> 35 ~ 50	> 50 ~ 100			+ 20℃	0℃	- 20℃	- 40℃
Q295	A	295	275	255	235	390 ~ 570	23
	B						23	34
Q345	A	345	325	295	275	470 ~ 630	21
	B						21	34
	C						22		34
	D						22			34
	E						22				27
Q390	A	390	370	350	330	490 ~ 650	19
	B						19	34
	C						20		34
	D						20			34
	E						20				27
Q420	A	420	400	380	360	520 ~ 680	18
	B						18	34
	C						19		34
	D						19			34
	E						19				27
Q460	C	460	440	420	400	550 ~ 720	17		34
	D						17			34
	E						17				27

（2）Comparison of Standard Grades for New and Old Low-Alloy Steels (See Table 3-1-9)

Table 3-1-9 Comparison of Standard Grades for New and Old Low-Alloy Steels

New standard GB/T1591-1994	Old standard GB 1591-1988
Q295	09Mnv、09MnNb、09Mn2、12Mn
Q345	18Nb、09MnCupTi、10MnsiCu、12Mnv、14MnNb、16Mn、16MnRE
Q390	10MnpNbRE、15Mnv、15MnTi、16MnNb
Q420	14MnvTiRE、15MnvN
Q460	-

(四) Alloy structural steel

(1) Mechanical properties of alloy structural steel (see Table 3-1-11)

Table 3-1-10 Characteristics and applications of low alloy high strength structural steel

the name of a shop	Main Features	Use examples
Q295	The steel contains only a small amount of alloy elements, the strength is not high, but has good plasticity, cold bending, welding and corrosion resistance	Building structures, industrial plants, low-pressure boilers, low and medium pressure chemical containers, oil tanks, pipelines, cranes, tractors, vehicles and general engineering structures with low strength requirements
Q345 Q390	The steel has good mechanical properties, good weldability, cold and hot working properties and corrosion resistance. Grade C, D and E steel has good low temperature toughness.	Ships, boilers, pressure vessels, oil storage tanks, Bridges, power station equipment, lifting and transportation machinery and other high load welding structures
Q420	High strength, especially in the state of normalizing or normalizing and tempering, has high comprehensive mechanical properties	Large ships, Bridges, power station equipment, medium and high pressure boilers, high pressure vessels, locomotive vehicles, lifting machinery, mining machinery and other large welded structural parts
Q460	The highest strength is achieved in normalizing, normalizing with tempering, or quenching with tempering, resulting in excellent comprehensive mechanical properties. All steels are deoxidized using aluminum, with quality grades C, D, and E, ensuring good toughness.	Reserve steel, used in various large engineering structures and light structures requiring high strength and heavy load

Table 3-1-11 Mechanical properties of alloy structural steel

Steel Group		order number		the name of a shop	Sample blank size (mm)		heat treatment										Mechanical Performance										Steel annealing or high temperature tempering Availability Brinell hardness BHs100 /3000 ≤
							quench						tempering				tensile strength σb /Mpa		yield point σe /Mpa		Post-break elongation δ5 （%）		contraction of area ψ （%）		shock absorption Power Aku2 /J
							heating temperature /℃				coolant		heating temperature /℃		coolant
							first Secondary quench		second Secondary quench
																	≥
Mn		1		20Mn2	15		850		-		Water, oil		200		Water, Air		785		590		10		40		47		187
							880		-		Water, oil		440		Water, Air
		2		30Mn2	25		840		-		water		500		water		785		635		12		45		63		207
		3		35Mn2	25		840		-		water		500		water		835		685		12		45		55		207
		4		40Mn2	25		840		-		Water, oil		540		water		885		735		12		45		55		217
		5		45Mn2	25		840		-		oil		550		Water, oil		885		735		10		45		47		217
		6		50Mn2	25		820		-		oil		550		Water, oil		930		785		9		40		39		229
Mn V		7		20MnV	15		880		-		Water, oil		200		Water, Air		785		590		10		40		55		187
si Mn		8		27siMn	25		920		-		water		450		Water, oil		980		835		12		40		39		217
		9		35siMn	25		900		-		water		570		Water, oil		885		735		15		45		47		229
		10		42siMn	25		880		-		water		590		water		885		735		15		40		47		229
siM nMo V		11		20siMn2MoV	sample		900		-		oil		200		Water, Air		1380		-		10		45		55		269
		12		25siMn2MoV	sample		900		-		oil		200		Water, Air		1470		-		10		40		47		269
		13		37siMn2MoV	25		870		-		Water, oil		650		Water, Air		980		835		12		50		63		269
	B		14	40B		25		840		-		water		550		water		785		635		12		45		55		207
			15	45B		25		840		-		water		550		water		835		685		12		45		47		217
			16	50B		20		840		-		oil		600		empty		785		540		10		45		39		207
	MnB		17	40MnB		25		850		-		oil		500		Water, oil		980		785		10		45		47		207
			18	45MnB		25		840		-		oil		500		Water, oil		1030		835		9		40		39		217
	Mn MOB		19	20MnMOB		15		880		-		oil		2000		Oil, Air		1080		885		10		50		55		207
	Mn vB		20	15MnvB		15		860		-		oil		200		Water, Air		885		635		10		45		55		207
			21	20MnvB		15		860		-		oil		200		Water, Air		1080		885		10		45		55		207
			22	40MnvB		25		850		-		oil		520		Water, oil		980		785		10		45		47		207
	Mn TiB		23	20MnTiB		15		860		-		oil		200		Water, Air		1130		930		10		45		55		187
			24	25 MnTiBRE		sample		860		-		oil		200		Water, Air		1380		-		10		40		47		229
cr			25	15cr		15		880		780 ~ 820		Water, oil		200		Water, Air		735	490		11		45		55		179
			26	15crA		15		880		770 ~ 820		Water, oil		180		Oil, air		685	490		12		45		55		179
			27	20cr		15		880		780 ~ 820		Water, oil		200		Water, Air		835	540		10		40		47		179
			28	30cr		25		860		-		oil		500		Water, oil		885	685		11		45		47		187
			29	35cr		25		860		-		oil		500		Water, oil		930	735		11		45		47		207
			30	40cr		25		850		-		oil		520		Water, oil		980	785		9		45		47		207
			31	45cr		25		840		-		oil		520		Water, oil		1030	835		9		40		39		217
			32	50cr		25		830		-		oil		520		Water, oil		1080	930		9		40		39		229
crsi			33	38crSi		25		900		-		oil		600		Water, oil		980	835		12		50		55		255

	cr Mo	34	12crMo		30	900	-	empty	650	empty	410	265	24	60	110	179
		35	15crMo		30	900	-	empty	650	empty	440	295	22	60	94	179
		36	20crMo		15	880	-	Water, oil	500	Water, oil	885	685	12	50	78	197
		37	30crMo		25	880	-	Water, oil	540	Water, oil	930	785	12	50	63	229
		38	30crMoA		15	880	-	oil	540	Water, oil	930	735	12	50	71	229
		39	35crMo		25	850	-	oil	550	Water, oil	980	835	12	45	63	229
		40	42crMo		25	850	-	oil	560	Water, oil	1080	930	12	45	63	217
	crM ov	41	12crMov		30	970	-	empty	750	empty	440	225	22	50	78	241
		42	35crMov		25	900	-	Oil	630	Water, oil	1080	930	10	50	71	241
		43	12cr1Mov		30	970	-	empty	750	empty	490	245	22	50	71	179
		44	25cr2MovA		25	900	-	oil	640	empty	930	785	14	55	63	241
		45	25cr2MolvA		25	1040	-	empty	700	empty	735	590	16	50	47	241
	crM oAl	46	38crMoAl		30	940	-	Water, oil	640	Water, oil	980	835	14	50	71	229
	crv	47	40crv		25	880	-	oil	650	Water, oil	885	735	10	50	71	241
		48	50crvA		25	860	-	oil	500	Water, oil	1280	1130	10	40	-	255
	cr Mn	49	15crMn		15	880	-	oil	200	Water, Air	785	590	12	50	47	179
		50	20crMn		15	850	-	oil	200	Water, Air	930	735	10	45	47	187
		51	40crMn		25	840	-	oil	550	Water, oil	980	835	9	45	47	229
crM nsi		52		20crMnsi	25	880	-	oil	480	Water, oil	785	635	12	45	55	207
		53		25crMnsi	25	880	-	oil	480	Water, oil	1080	885	10	40	39	217
		54		30crMnsi	25	880	-	oil	520	Water, oil	1080	885	10	45	39	229
		55		30crMnsiA	25	880	-	oil	540	Water, oil	1080	835	10	45	39	229
		56		35crMnsiA	sample	Heat to 880°C and then quench isothermally at 280–310°C					1620	1280	9	40	31	241
					sample	950	890	oil	230	Air, Oil
crM nMo		57		20crMnMo	15	850	-	oil	200	Water, Air	1180	885	10	45	55	217
		58		40crMnMo	25	850	-	oil	600	Water, oil	980	785	10	45	63	217
crM nTi		59		20crMnTi	15	880	870	oil	200	Water, Air	1080	850	10	45	55	217
		60		30crMnTi	sample	880	850	oil	200	Water, Air	1470	-	9	40	47	229
crNi		61		20crNi	25	850	-	Water, oil	460	Water, oil	785	590	10	50	63	197
		62		40crNi	25	820	-	oil	500	Water, oil	980	785	10	45	55	241
		63		45crNi	25	820	-	oil	530	Water, oil	980	785	10	45	55	255
		64		50crNi	25	820	-	oil	500	Water, oil	1080	835	8	40	39	255
		65		12crNi2	15	860	780	Water, oil	200	Water, Air	785	590	12	50	63	207
		66		12crNi3	15	860	780	oil	200	Water, Air	930	685	11	50	71	217
	crNi	67		20crNi3	25	830	-	Water, oil	480	Water, oil	930	735	11	55	78	241
		68		30crNi3	25	820	-	oil	500	Water, oil	980	785	9	45	63	241
		69		37crNi3	25	820	-	oil	500	Water, oil	1130	980	10	50	47	269
		70		12cr2Ni4	15	860	780	oil	200	Water, Air	1080	835	10	50	71	269
		71		20cr2Ni4	15	880	780	oil	200	Water, Air	1180	1080	10	45	63	269
	crN iMo	72		20crNiMo	15	850	-	oil	200	empty	980	785	9	40	47	197
		73		40crN iMoA	25	850	-	oil	600	Water, oil	980	835	12	55	78	269
	crMn NiMo	74		18crMn NiMoA	15	830	-	oil	200	empty	1180	885	10	45	71	269
	crN iMoV	75		45crN iMoVA	sample	860	-	oil	460	oil	1470	1330	7	35	31	269
	crN iW	76		18cr2N i4WA	15	950	850	empty	200	Water, Air	1180	835	10	45	78	269
		77		25cr2N i4WA	25	850	-	oil	550	Water, oil	1080	930	11	45	71	269

(2) Characteristics and applications of alloy structural steel (see Table 3-1-12)

Table 3-1-12 Properties and applications of alloy structural steel

the name of a shop	key property	Example
20Mn2	20Mu2 and 20cr steels, which are of medium strength and relatively small cross-sectional dimensions, exhibit similar properties. However, 20Mu2 outperforms 20cr in low-temperature impact toughness and weldability. It demonstrates superior cold deformation plasticity and excellent machinability. Moreover, 20Mu2 exhibits higher hardenability than corresponding carbon steels and shows increased susceptibility to overheating, decarburization, and temper brittleness during heat treatment.	Designed for manufacturing carburized components with cross-sections under 50mm, including small gears, shafts, crosshead pins (with low mechanical requirements), piston pins, diesel engine sleeves, valve lifters, transmission gear levers, and steel bushings. Additionally, it is suitable for producing bolts, screws, nuts, and riveted or welded parts after hot rolling and normalizing processes.
the name of a shop	key property	Example
30Mn2	30Mn2 steel is typically used after quenching and tempering treatment, offering high strength, excellent toughness, and superior wear resistance. When manufacturing small cross-sectional components, it demonstrates good static strength and fatigue strength. The material exhibits favorable workability for drawing, cold heading, and heat treatment processes, with moderate machinability and acceptable weldability. Welding is generally not recommended for this grade, but when necessary, parts should be preheated to over 200°C. It demonstrates high hardenability with minimal deformation during quenching, though it is sensitive to overheating, decarburization, and temper brittleness.	Used in manufacturing vehicle frames, cross beams, transmission gears, shafts, cold heading bolts, and large-section quenched and tempered components for automobiles and tractors. It is also suitable for producing high-strength carburized parts, such as rear axle components for cranes.
35Mn2	With higher carbon content than 30Mn2, it exhibits superior strength and wear resistance, along with enhanced hardenability. However, its ductility is slightly reduced, maintaining moderate plasticity during cold deformation and average machinability. The material demonstrates poor weldability and is susceptible to white spot defects, overheating tendency, and temper brittleness. Additionally, it is prone to cracking under water cooling conditions. These characteristics make it generally suitable for quenching and tempering or normalizing processes.	When producing parts with a diameter smaller than 20mm, 40cr can be used as a substitute. It is suitable for manufacturing various cold-drawn bolts with a diameter under 15mm, small shafts, bushings, connecting rods, control rods, crankshafts, fan components, and implements such as hoe handles and shovels in agricultural machinery, where high mechanical performance is required.
40Mn2	Medium-carbon tempered manganese steel outperforms 40 steel in strength, ductility, and wear resistance, while offering excellent heat treatment and machinability. However, its poor weldability requires preheating to 100-425°C before welding. The material exhibits temper brittleness, overheating sensitivity, and tendency to crack under water cooling. It is typically used in tempered condition.	These components are designed for heavy-duty machinery applications, including crankshafts, axle shafts, half-shafts, levers, connecting rods, control rods, worms, piston rods, load-bearing bolts, screws, reinforcement rings, and springs. When producing parts with diameters under 40mm, their static strength and fatigue performance match those of 40cr steel, making it a suitable replacement for critical small-diameter components.
45Mn2	Medium carbon tempered steel exhibits high strength, wear resistance, and hardenability. After quenching and tempering, it achieves excellent comprehensive mechanical properties, making it suitable for oil-quenched and tempered at high temperatures. It is typically used in tempered condition but can also be employed in normalized state when necessary. While demonstrating decent machinability, it suffers from poor weldability. The material shows low plasticity during cold deformation and exhibits overheating sensitivity along with temper brittleness tendency during heat treatment. Additionally, water quenching tends to induce cracks.	This material is designed for manufacturing components that endure high stress and wear resistance. When producing parts with diameters below 60mm, it can substitute 40cr steel. It is widely used in automotive, tractor, and general machinery industries for manufacturing shafts, axle components, universal joint shafts, worm gears, gear shafts, gears, connecting rod covers, friction discs, carriage axles, tram and steam locomotive axles, heavy-duty machine frames, as well as cold-drawn bolts and nuts.
50Mn2	Medium-carbon tempered high-strength manganese steel exhibits exceptional strength, high elasticity, and excellent wear resistance. It demonstrates superior hardenability and good machinability, though it shows low cold deformation plasticity and poor weldability. The material is susceptible to overheating sensitivity, white spot sensitivity, and temper brittleness. Water cooling may induce cracks. Through appropriate tempering treatment, it achieves excellent comprehensive mechanical properties. Typically used after tempering, it can also be employed after normalizing and tempering processes.	This material is specifically designed for manufacturing large components subjected to high stress and wear, including gear shafts, crankshafts, various shafts, connecting rods, worms, universal joint shafts, and gears in general machinery; drive shafts and spline shafts in automobiles; mandrels with severe impact loads; main shafts and shafts supported by rolling bearings in heavy machinery; as well as large gears. It is also used in the production of hand-wound springs and leaf springs. When manufacturing parts with a diameter less than 80mm, it can replace 45cr steel.
20Mnv	20Mn delivers superior performance, serving as a viable alternative to 20cr and 20crNi. It outperforms 15cr and 20Mn2 in strength, toughness, and ductility, with excellent hardenability and satisfactory machinability. After carburizing, it can be directly quenched without requiring secondary quenching to refine the core structure. While demonstrating good weldability, it exhibits temper embrittlement during heat treatment at 300-360°C.	Welded components for high-pressure vessels, boilers, and large high-pressure pipelines (operating at temperatures not exceeding 450-475°C) are produced. These components are also used in cold-rolled, cold-drawn, and cold-stamped parts such as gears, bicycle chains, and piston pins. Additionally, they are widely used in manufacturing mining chain links with diameters under 20mm.
27siMn	27siMn outperforms 30Mn2 with superior strength and wear resistance, along with excellent hardenability. It demonstrates moderate cold deformation plasticity and good machinability, while maintaining acceptable weldability. During heat treatment, its toughness shows minimal reduction and retains high toughness even under water cooling. However, it exhibits overheating sensitivity, white spot sensitivity, and a tendency to develop temper brittleness. Primarily used after quenching and tempering, it can also be utilized in normalized or hot-rolled forms.	Used to manufacture high toughness, high wear resistance hot stamped parts, such as tractor track pins, which do not require heat treatment or normalizing
35siMn	Tempered alloy steel, with excellent properties, can replace 40cr and partially substitute 40crNi. After quenching and tempering, it exhibits high static strength, fatigue strength, and wear resistance, along with good toughness. It demonstrates excellent hardenability, moderate plasticity during cold deformation, and favorable machinability. However, its weldability is poor, requiring preheating before welding. The steel is also susceptible to overheating sensitivity, white spot sensitivity, and temper brittleness, and is prone to decarburization.	Tempered and tempered steel is used to manufacture medium-speed, medium-load components. Quenched and tempered steel is employed for high-load, low-impact vibration components and parts with large cross-sections and surface hardening, such as turbine main shafts and hubs (diameter <250mm, operating temperature <400°C), impellers (thickness <170mm), and critical fasteners. It also serves general machinery components including drive shafts, main shafts, center shafts, connecting rods, gears, worms, tram axles, generator shafts, crankshafts, flywheels, and various forgings. In agricultural machinery, it is used for wear-resistant parts like hoe handles and plowshares. Additionally, it can produce thin-walled seamless steel pipes.
42siMn	The steel's performance is comparable to 35siMn, with slightly superior strength, wear resistance, and hardenability. Under certain conditions, it outperforms 40cr in strength, wear resistance, and hot workability, and can even replace 40crNi.	For medium-speed and medium-load gear transmission components, the material undergoes high-frequency quenching and medium-temperature tempering. When subjected to high-frequency quenching followed by low-temperature tempering, it is used to manufacture parts with large cross-sections that exhibit high surface hardness and superior wear resistance, such as gears, main shafts, and shafts. For medium-speed and heavy-load applications, including main shafts, gears, hydraulic pump rotors, and sliders, the material is processed through low-temperature or medium-temperature tempering after quenching.
20siMn 2MOv	This high-strength, high-toughness low-carbon quenched structural steel exhibits excellent hardenability with minimal oil-cooling deformation and crack tendency. It demonstrates low decarburization tendency, good forgeability, and superior weldability. For complex-shaped components, preheating to 300°C before welding and slow cooling after welding are recommended. However, its poor machinability limits its application, typically used in quenched and low-temperature tempered conditions.	In low-temperature tempering conditions, this material can substitute for medium-carbon alloy structural steels such as 35crMO, 35crNi3MOA, and 40crNiMOA used in quenched and tempered conditions. It is suitable for manufacturing heavy-duty components with complex stress conditions or those requiring long-term operation at low temperatures, including lifting tools, lifting rings, perforating guns, and other large-section connectors in petroleum machinery.
25siMn 2MoA	The performance is essentially identical to that of 20siMn2MoV, but it exhibits slightly higher strength and hardenability, while showing a slight decrease in plasticity and toughness.	The application is basically the same as 20siMn2MoV. The oil drilling machine lifting ring and other parts made of this steel have good performance, are safer and more reliable than the similar parts made of 35crNi3Mo and 40crNiMo, and are light in weight and save material.
37siMn 2MoV	Advanced quenched and tempered steel features excellent comprehensive mechanical properties, favorable heat treatment characteristics, superior hardenability, low sensitivity to quench cracking, high stability during tempering, minimal tendency to develop temper brittleness, and outstanding high-temperature strength as well as low-temperature toughness. It achieves high strength and toughness through quenching and tempering treatment, and is typically used in quenched and tempered condition.	This tempered steel is engineered for heavy-duty applications, including gearboxes, shafts, connecting rods, rotors, and high-pressure seamless steel pipes in heavy machinery. It also serves as high-pressure vessels and large bolts for petrochemical industries, along with high-temperature fasteners (operating below 450°C). After quenching and low-temperature tempering, it delivers ultra-high strength, making it a superior alternative to 35CrMo and 40CrNiMo steels.
40B	It has higher hardness, toughness and hardenability than 40 steel, and good comprehensive mechanical properties after tempering. It can replace 40cr and is generally used in tempered state.	It is used to manufacture parts with larger cross-sections than 40cr and higher performance requirements, such as shafts, tie rods, gears, cams, and tractor crankshafts. It can also be used to make small cross-section parts instead of 40cr.
45B	It outperforms 45 steel in strength, wear resistance, and hardenability. Typically used in quenched and tempered conditions, it can replace 40cr steel.	It is used to manufacture parts with large cross-section and high strength requirements, such as tractor connecting rod, crankshaft and other parts. It can be used instead of 40cr for small size parts with low performance requirements.
50B	After tempering, the comprehensive mechanical properties are higher than those of 50 steel, with good hardenability. The hardness is low when tempered, and the cutting properties are acceptable. It is generally used in tempered state. Because of the poor resistance to tempering, the tempering temperature should be reduced by about 50℃.	Used to replace 50,50Mn, and 50Mn2 in manufacturing various parts with higher strength, better hardenability, and smaller cross-sectional dimensions, such as cams, shafts, gears, and steering tie rods.
40MnB	This material exhibits high strength and hardness with excellent plasticity and toughness. After high-temperature tempering, it demonstrates good low-temperature impact toughness. When subjected to quenching and tempering or quenching followed by low-temperature tempering, its dynamic load-bearing capacity improves. Its hardenability is comparable to 40cr, but it shows lower temper stability and a tendency to develop temper brittleness. It possesses excellent cold and hot workability, with an operating temperature range of-20 to 425°C. It is typically used in quenched and tempered conditions.	This material is used to manufacture medium and small critical quenched and tempered components for tractors, automobiles, and other general machinery, including automotive half-shafts, steering shafts, spline shafts, worms, machine tool spindles, and gear shafts. It can replace 40cr in producing larger cross-section parts such as winch shafts, and substitute 40crNi in small-sized component manufacturing.
45MnB	The strength and hardenability are higher than 40cr, but the plasticity and toughness are slightly lower. The hot working properties and cutting properties are good. The grain growth, oxidation and decarburization, and deformation of heat treatment are small when heated. The use is in tempered state.	This material is used to replace 40cr, 45cr, and 45Mn2 for manufacturing medium and small cross-section wear-resistant tempered parts and high-frequency quenched components, such as drilling machine spindles, tractor crankshafts, machine tool gears, cams, spline shafts, crankshafts, idler wheels, left-right split forks, and bushings.

15MnvB	Low-carbon martensitic quenched steel can completely replace 40cr steel. After low-temperature quenching and tempering, it has high strength, good plasticity and low-temperature impact toughness, low notch sensitivity, good hardenability and good welding properties.	The process of quenching and low-temperature tempering is used to manufacture high-strength important bolt parts, such as cylinder head bolts, half shaft bolts, and connecting rod bolts in automobiles. It can also be used to manufacture medium-load carburized parts.
20MnvB	Cyanide-hardened steel shares similar properties with 20crMnTi and 20crNi, featuring high strength, excellent wear resistance, and good hardenability. It demonstrates superior machinability and processing characteristics for carburizing and heat treatment. While it can undergo direct quenching after carburizing, it exhibits slightly greater deformation and decarburization during quenching compared to 20crMnTi. This material can effectively replace 20crMnTi, 20cr, and 20crNi in various applications.	It is commonly used to manufacture small and medium carburized parts with heavy loads, such as shafts in heavy machinery, large module gears, and main and driven gears in automobile rear axle
40MnvB	Comprehensive mechanical properties surpass those of 40cr, featuring high strength, toughness, and plasticity. It exhibits excellent hardenability, low overheating sensitivity during heat treatment, and superior cold-drawing processability and machinability. The material performs optimally when tempered and hardened.	Commonly used as a substitute for 40cr, 45cr, and 38crsi in manufacturing parts requiring low-temperature, medium-temperature, or high-temperature tempering. It also replaces 42crMo and 40crNi in producing critical heat-treated components such as gears and shafts for machine tools and automobiles.
20MnTiB	It has good mechanical properties and processing properties, and good machinability after normalizing, and high fatigue strength after heat treatment	It is widely used in the production of various small and medium-sized gears and carburized components for automobiles and tractors, and can replace 20 crMnTi.
25 MnTiBRE	This steel outperforms 20crMnTi in comprehensive mechanical properties, featuring excellent workability and good hardenability. It demonstrates superior cold/hot workability with a broad forging temperature range. After normalizing, it exhibits superior machinability. The addition of RE enhances low-temperature impact toughness while reducing notch sensitivity. Although its heat treatment deformation is slightly higher than chromium steel, this characteristic can be controlled through optimized process parameters.	Commonly used as a substitute for 20crMnTi and 20crMo, this material is employed in manufacturing medium-load tractor gears (carburized), bulldozer components, and transmission gears and shafts for medium and small automobiles, all of which are carburized or carbon-nitrogen co-deposited parts.
15cr	Low carbon alloy carburized steel has higher strength and hardenability than 15 steel, high cold deformation plasticity, good weldability, and good machinability after annealing. For parts with low performance requirements and simple shape, carburized steel can be directly quenched after carburizing, but it has large deformation after heat treatment and has temper brittleness. Generally, it is used as carburized steel.	This material is designed for manufacturing various hardened parts with surface wear resistance, high core strength and toughness, and operational speeds below 30mm in cross-sectional dimensions. Typical applications include crankpins, piston pins, piston rings, couplings, small camshafts, bevel gears, slide valves, pistons, bushings, bearing rings, screws, and rivets. It also serves as quenched steel for producing small components that require specific strength and toughness while accommodating greater deformation tolerance.
20cr	This steel exhibits superior strength and hardenability compared to 15cr and 20 steel. After quenching and low-temperature tempering, it achieves excellent comprehensive mechanical properties and low-temperature impact toughness without developing temper brittleness. During carburizing, the grain structure tends to grow, necessitating secondary quenching to enhance core toughness. However, cooling quenching is not recommended. It demonstrates high plasticity during cold bending and can be wire-drawn. After high-temperature normalizing or tempering, it exhibits good machinability and weldability (typically requiring preheating to 100-150°C before welding). Generally used as a carburized steel, it maintains superior performance across these applications.	This process is used to manufacture small-section components (under 30mm) with simple geometries, high rotational speeds, low loads, wear-resistant surfaces, and high core strength. Typical applications include carburized or carburitized parts such as small gears, shafts, valves, piston pins, bushing ratchets, trays, cams, worms, and toothed clutches. For components requiring minimal heat treatment deformation and high wear resistance, general quenching or high-frequency quenching is recommended after carburizing. This method is also suitable for small-module gears (under 3mm), spline shafts, and shafts. Additionally, the resulting tempered steel can be used to produce components for low-speed, medium-load (impact) applications.
30cr	The strength and hardenability are higher than 30 steel. The cold bending plasticity is good, and the cutting processing is good after annealing or high temperature tempering. The weldability is medium. It is generally used after tempering, but also can be used after normalizing.	It is used to manufacture various parts that are wear-resistant or impact-resistant, such as gears, rollers, shafts, levers, rocker arms, connecting rods, bolts, nuts, etc. It can also be used as high-frequency surface hardening steel to manufacture parts that are wear-resistant and have high surface hardness.
35cr	Medium carbon alloy tempered steel has high strength and toughness. Its strength is higher than 35 steel, and its hardenability is slightly higher than 30cr. Its properties are basically similar to 30cr.	Used to manufacture gears, shafts, rollers, bolts and other important tempered parts, the use is basically the same as 30cr
40cr	After quenching and tempering treatment, the material exhibits excellent comprehensive mechanical properties, low-temperature impact toughness, and low notch sensitivity. It demonstrates good hardenability, achieving high fatigue strength when quenched in oil. However, complex-shaped parts are prone to cracking when quenched in water. The material has moderate cold bending plasticity. While it offers good machinability after normalizing or quenching and tempering, its poor weldability makes it susceptible to cracking. Preheating to 100-150°C is recommended before welding. Generally used in quenched and tempered conditions, it can also undergo carbon nitride diffusion treatment and high-frequency surface hardening.	One of the most widely used steel grades, this material is quenched and tempered for manufacturing medium-speed, medium-load components such as machine tool gears, shafts, worms, spline shafts, and center sleeves. After quenching and high-frequency surface hardening, it becomes suitable for high-hardness, wear-resistant parts including gears, shafts, spindles, crankshafts, mandrels, sleeves, pins, connecting rods, screws, nuts, and intake valves. For heavy-duty, medium-speed impact applications, it undergoes quenching and medium-temperature tempering to produce components like hydraulic pump rotors, sliders, gears, and spindle rings. Low-temperature tempering is applied for heavy-load, low-impact wear-resistant parts such as worms, spindles, and sleeve rings. Carbon-nitrogen co-infiltration treatment enables the production of large-sized transmission components with high low-temperature impact toughness, including shafts and gears. Alternative steels to 40cr include 40MnB, 45MnB, 35siMn, 42siMn, 40MnvB, 42Mnv, 40MnMOB, and 40MnwB.
45cr	It outperforms 40cr in strength, wear resistance, and hardenability, though with slightly lower toughness, while maintaining comparable properties.	Similar to 40cr, it is mainly used for manufacturing high-frequency surface hardened shafts, gears, sleeves, pins, etc.
50cr	This material exhibits excellent hardenability. After oil quenching and tempering, it achieves high strength and hardness. However, water quenching tends to induce cracks. While demonstrating good machinability, it shows low plasticity during cold bending and poor weldability with a tendency to crack. Preheating to 200°C before welding and post-weld heat treatment to relieve stress are recommended. It is typically used in quenched and tempered or tempered and tempered conditions.	This material is used to manufacture heavy-duty, wear-resistant components such as hot-rolled rollers under 600mm, drive shafts, gears, thrust rings, support roller spindles, diesel engine connecting rods, push rods, tractor clutches, and bolts. It also serves for high-strength oil film bearing sleeves and gears in heavy mining machinery, as well as high-frequency surface-hardened parts and medium-elasticity springs.
38crsi	It has high strength, high wear resistance and toughness, good hardenability, high low temperature impact toughness, good temper stability, good cutting performance, poor weldability, and is generally used after hardening and tempering	Generally used in the manufacture of 30 ~ 40mm diameter parts with high strength and wear resistance requirements, such as small module gears, fork shafts, track shafts, small shafts, lifting hooks, bolts, intake valves, rivet machine press heads in tractors, automobiles and other machinery and equipment.
12crMo	Heat-resistant steel has high thermal strength, no thermal brittleness, good cold deformation plasticity and cutting properties, and acceptable welding properties. It is generally used after normalizing and high temperature tempering.	After normalizing and tempering, it is used to manufacture main steam pipes for boilers and steam turbines with a steam temperature of 510℃, and various pipes and superheater pipes whose wall temperature does not exceed 540℃. After quenching and tempering, it can also be used to manufacture various high-temperature elastic parts.
15crMo	Pearlitic heat-resistant steel exhibits superior strength to 12crMo but with slightly reduced toughness. It demonstrates high creep strength below 500-550°C, along with excellent machinability and cold-strain plasticity. The weldability is satisfactory, requiring preheating to 300°C before welding and post-weld heat treatment. This steel is typically employed in normalizing and high-temperature tempering conditions.	After normalizing and high-temperature tempering, it is used to manufacture superheaters for boilers with steam temperatures up to 510°C, medium and high-pressure steam pipes, and headers. It is also suitable for main steam pipes with steam temperatures up to 510°C. After quenching and tempering, it can be used to manufacture various critical components for normal-temperature operation.
20crMo	It has high thermal strength, high thermal strength at 500 ~ 520℃, good hardenability, no temper brittleness, good cold strain plasticity, cutting properties and weldability, and is generally used in tempered or carburized and hardened state	This material is designed for manufacturing high-pressure pipes and fasteners in chemical equipment for non-corrosive media and operating temperatures below 250°C (454°F), including nitrogen-hydrogen environments. It also serves critical components in steam turbines and boilers such as blades, diaphragms, forgings, and rolled profiles. Additionally, it functions as a substitute for 1Cr13 steel in general machinery, particularly for critical carburized parts like gears and shafts. The material is also suitable for pressure-stage working blades in medium and low-pressure steam turbines operating in superheated steam zones.
30crMo	It has high strength and toughness, good high temperature strength below 500℃, good cutting properties, moderate cold bending plasticity, high hardenability, good welding properties, and is generally used in tempered state	Designed for manufacturing pipes operating below 400°C, fasteners for boilers and steam turbines below 450°C, nuts and flanges for high-pressure applications below 500°C, heavy-duty components in general machinery including main shafts, gears, bolts, and control wheels, high-pressure pipes for chemical equipment below 250°C in nitrogen-hydrogen environments, and welded components.
35crMo	This material demonstrates exceptional high-temperature creep strength and creep resistance, along with excellent low-temperature impact toughness. It can withstand operating temperatures up to 500°C in high-temperature environments and-110°C in low-temperature conditions. The material exhibits superior static strength, impact toughness, and fatigue resistance. It features good hardenability without overheating tendency, minimal deformation during quenching, and acceptable plasticity under cold deformation. While showing moderate machinability, it exhibits first-class temper brittleness. Poor weldability requires preheating to 150-400°C before welding, followed by post-weld heat treatment to relieve residual stresses. Typically used after quenching and tempering, it can also be applied in high/medium frequency surface hardening processes or after quenching combined with low/medium temperature tempering.	These components are critical for manufacturing machinery designed to withstand impacts, bending/torsion, and heavy loads. Key applications include: V-gears in rolling mills, crankshafts, hammer rods, connecting rods, fasteners, steam turbine main shafts, vehicle axles, engine transmission parts, large electric motor shafts, perforating tools in oil machinery, boiler bolts for operating below 400°C, nuts for below 510°C environments, and high-pressure seamless thick-walled conduits (operating at 450-500°C with non-corrosive media) in chemical equipment. Additionally, they can replace 40 CrNi steel in producing high-load drive shafts, steam turbine generator rotors, large-section gears, and support shafts (diameter <500mm).
42crMo	With performance comparable to 35crMo, this alloy exhibits superior strength and hardenability due to its higher carbon and chromium content. After quenching and tempering, it demonstrates high fatigue strength and resistance to multiple impacts, along with excellent low-temperature impact toughness. Notably, it shows no significant temper brittleness and is typically used after quenching and tempering.	Primarily used for manufacturing critical components requiring higher strength than 35crMo and larger cross-sectional dimensions, such as shafts, gears, connecting rods, transmission gears, turbocharger gears, engine cylinders, springs, spring clamps, 1200-2000mm oil drill pipe couplings, fishing tools, and as a substitute for high-nickel quenched and tempered steel.
12crMoV	Pearlitic heat-resistant steel exhibits superior high-temperature mechanical properties, demonstrating excellent cold deformation plasticity without annealing brittleness. It features favorable machinability and acceptable weldability (preheating is required for thick-walled components before welding, followed by post-weld heat treatment to relieve residual stresses). The material maintains operational stability across a broad temperature range, with service temperatures extending from-40°C to 560°C. It is typically employed in high-temperature normalizing and high-temperature tempering processes.	Manufactured for steam turbine applications, including main steam pipes operating at 540°C, guide vane rings, diaphragms, and various superheater tubes and ducts designed for temperatures up to 570°C.
35crMoV	High strength, good hardenability, poor weldability, low plasticity in cold deformation, after quenching and tempering	Used in the manufacture of critical components under high stress, such as turbine runner operating below 500-520°C, rotors, cover plates, shaft discs, generator shafts, and engine components for high-performance turbines and compressors.
12crlMoV	This steel exhibits a creep limit comparable to its tensile strength. It demonstrates exceptional plasticity under prolonged tension, with superior oxidation resistance and thermal strength compared to 12 CrMoV. The material also features excellent workability and weldability (requiring preheating before welding and post-weld heat treatment to relieve stress). It is typically used after normalizing and high-temperature tempering.	For manufacturing overheated steel pipes, conduits, radiator tubes, and related forgings for high-pressure equipment operating at temperatures not exceeding 570 to 585°C.
25 cr2MoVA	Medium carbon heat-resistant steel has high strength and toughness. It performs well at temperatures below 500℃ without heat brittleness tendency, with good hardenability and acceptable machinability. Its cold deformation plasticity is moderate, and its weldability is poor. It is generally used in tempered state, but can also be used after normalizing and high-temperature tempering.	It is used to manufacture nuts (≤550℃), bolts, and studs (≤530℃) under high-temperature conditions, fasteners with long-term working temperatures up to around 510℃, turbine integral rotors, sleeves, main steam valves, and regulating valves. It can also be used as nitrided steel for making valve stems, gears, etc.
38crMoAl	Advanced nitrided steel exhibits superior nitriding performance and mechanical properties, along with excellent heat resistance and corrosion resistance. After nitriding treatment, it achieves high surface hardness, exceptional fatigue strength, and excellent resistance to overheating, while being free from temper embrittlement. The material demonstrates satisfactory machinability and can operate at temperatures up to 500°C. However, it shows low plasticity during cold deformation, poor weldability, and limited hardenability. It is typically used after quenching and tempering or nitriding processes.	This material is designed for manufacturing small-sized nitrided components with exceptional fatigue resistance, high wear resistance, dimensional accuracy after heat treatment, and superior strength. Typical applications include cylinder liners, seat sleeves, base covers, piston bolts, gauges, precision grinding machine spindles, lathe spindles, boring bars, precision lead screws and gears, worms, high-pressure valves, valve stems, mold inserts, rollers, templates, turbine speed regulators, rotating sleeves, fixed sleeves, and various wear-resistant parts in plastic extruders.
40crv	Tempered steel has high strength and high yield point. Its comprehensive mechanical properties are better than 40cr. Its cold deformation plasticity and cutting properties are medium, and its overheating sensitivity is small. However, it has the tendency of temper brittleness and white spot sensitivity. It is generally used in tempered state.	Manufactured for critical components requiring variable loads and high stress, including locomotive connecting rods, crankshafts, push rods, propellers, cross beams, bushing supports, double-ended studs, screws, non-carburized gears, nitrided gears and pins, high-pressure boiler water pump shafts (diameter <30mm), high-pressure cylinders, steel pipes, and bolts (operating temperature below 420°C, 30MPa).
50crv	The alloy spring steel has good comprehensive mechanical properties and processability, good hardenability, good temper stability, high fatigue strength, the highest working temperature can reach 500℃, good low temperature impact toughness, poor weldability, usually after quenching and medium temperature tempering	Manufactured for various springs and mechanical components operating below 210°C, including engine valve springs, fuel injector springs, boiler safety valve springs, and automotive shock absorbers.
15c rMn	A high-toughness carburized steel with excellent surface hardness and wear resistance, suitable for replacing 15crM0.	Manufacturing gears, worm gears, plastic molds, steam turbine oil seals, and steam turbine bushings
20 crMn	Carburized steel has high strength and toughness, good hardenability, and better performance than 20cr after heat treatment. It has less deformation after quenching, good low-temperature toughness, and good machinability, but low welding properties. It is generally used after carburizing, quenching, or tempering.	It is used to manufacture heavy-duty, large-section tempered parts and small-section carburized parts. It can also be used to manufacture medium-load, small and medium-sized parts with less impact instead of 20crNi, such as gears, shafts, friction wheels, and sleeves of worm speed regulators.
40crMn	Excellent hardenability and high strength, suitable to replace 42crM0 and 40crNi	Manufacturing of pump shaft and connecting rod under high speed and high bending load working conditions, gear pump without strong impact load, pump rotor, clutch, high pressure container cover bolt, etc.
20crMnsi	It has high strength and toughness, high plasticity in cold deformation processing, good stamping performance, suitable for cold drawing, cold rolling and other cold working processes, good welding performance, low hardenability, large temper brittleness, generally not used for carburizing or other heat treatment, when necessary, it can also be used after quenching and tempering	Used for manufacturing high-strength welded parts, parts with good toughness for tensile force, as well as thin sheet stamping parts, cold drawing parts and cold stamping parts with thickness less than 16mm, such as large cross-section chains, chain rings and bolts in mining equipment.
25crMnsi	It exhibits higher strength than 20crMnsi but demonstrates lower toughness. However, after heat treatment, it shows improved strength, plasticity, and toughness.	Manufacture tie rods, critical welded and stamped components, and high-strength welded structures
30crMnsi	High-strength quenched and tempered structural steel features exceptional strength and toughness, superior hardenability, moderate cold deformation plasticity, and excellent machinability. However, it exhibits temper brittleness tendency and poor transverse impact toughness. While demonstrating good weldability, thicker sections exceeding 3mm require preheating to 150°C and post-weld heat treatment. This material is typically used after quenching and tempering.	It is mainly used in the manufacture of various important parts with heavy load and high speed, such as gear, shaft, clutch, sprocket, grinding wheel shaft, bushing, bolt, nut, etc. It is also used in the manufacture of parts with low working temperature and wear resistance, and welded components with variable load, such as high pressure blower blade, valve plate and non-corrosive pipe
35crMnsi	High-strength low-alloy steel exhibits excellent mechanical properties after heat treatment, featuring high strength, sufficient toughness, good hardenability, weldability (with preheating before welding), and formability. However, its corrosion and oxidation resistance are limited, and it is typically used at temperatures below 200°C, usually after low-temperature tempering or isothermal quenching.	It is used to manufacture medium speed, heavy load and high strength parts and components, such as aircraft landing gear and high strength parts, high pressure blower blades. When manufacturing small section parts, it can partially replace the corresponding chromium nickel molybdenum alloy steel.
20crMnMo	This high-strength advanced carburized steel exhibits superior strength to 15crMnMo, with slightly reduced plasticity and toughness. It outperforms 20crMnTi in hardenability and mechanical properties. After low-temperature quenching and tempering, it delivers excellent comprehensive mechanical performance and low-temperature impact toughness. The carburized quenched steel demonstrates high bending strength and wear resistance, though it tends to develop cracks during grinding and has poor weldability. Suitable for resistance welding, it requires preheating before welding and post-weld tempering. The material maintains good machinability and hot workability.	This material is commonly used to manufacture large, critical carburized components with high hardness, strength, and toughness (all exceeding 15crMnMo requirements), such as crankshafts, camshafts, connecting rods, gear shafts, gears, and pin shafts. It can also replace 12cr2Ni4.
40crMnso	After quenching and tempering, it has good comprehensive mechanical properties, good hardenability and high tempering stability. Most of them are used in quenched and tempered state.	Designed for manufacturing heavy-duty gear shafts, gears, rear axle half-shafts, shafts, eccentric shafts, connecting rods, and similar components for large trucks, as well as steam turbines. It can also replace 40crNiMo.
20crMnTi	Carburized steel can also be used as tempered steel. After quenching and low-temperature tempering, it has good comprehensive mechanical properties and low-temperature impact toughness. After carburizing, it has good wear resistance and bending strength. The heat treatment process is simple, and the hot and cold working properties are good. However, it has a tendency of temper brittleness when high-temperature tempering.	This widely used alloy structural steel is extensively applied in manufacturing critical components for automobiles and tractors. Designed for medium to heavy-duty applications, it features cross-sectional dimensions under 30mm, exceptional impact resistance, wear resistance, and high-speed performance. Typical applications include gear shafts, gear rings, gears, cross shafts, main shafts with sliding bearing supports, worms, and toothed clutches. In some cases, it can even replace 20 SiMoVB and 20 MnTiB steels.
30crMnTi	It is mainly used as titanium carburized steel, and sometimes can also be used as tempered steel. After carburizing and quenching, it has the characteristics of good wear resistance and high static strength. It has good heat treatment process. After carburizing, it can be directly cooled and quenched, and the deformation after quenching is very small. It has temper brittleness during high temperature tempering.	It is used to manufacture carburized parts with high core strength, such as gear shaft, gear, worm, etc., and can also be used to manufacture tempered parts, such as large cross-section driving gears on automobiles and tractors
20crNi	It has high strength, high toughness and good hardenability. After carburizing and quenching, the core has good toughness, high surface hardness, good cutting performance, medium plasticity during cold deformation, and poor weldability. The preheating should be 100 ~ 150℃ before welding. Generally, it is used after carburizing, quenching and tempering.	It is used to manufacture heavy-duty, large and important carburized parts, such as spline shaft, shaft, key, gear, piston pin, and can also be used to manufacture tempered parts with high impact toughness
40crNi	Medium carbon alloy tempered steel has high strength, high toughness and high hardenability. In tempered state, the comprehensive mechanical properties are good, the low temperature impact toughness is good, there is a tendency to backfire, easy to crack when water-cooled, good cutting properties, but poor weldability, used in tempered state	Used for forging and cold stamping of important tempered parts with large cross section size, such as connecting rod, disc, crankshaft, gear, shaft, screw, etc
45crNi	The performance is comparable to 40crNi. Due to its high carbon content, its strength and hardenability are slightly improved.	Used for manufacturing various critical components, similar to 40crNi, such as crankshafts for internal combustion engines, main shafts for automobiles and tractors, connecting rods, valves, and bolts.
50crNi	Performance is better than 45crNi	Can manufacture important shafts, crankshafts, drive shafts, etc
12crNi2	Low carbon alloy carburized structure steel has high strength, high toughness and high hardenability. It has medium plasticity during cold deformation, good low temperature toughness, good machinability and weldability. Large forgings have a tendency to form white spots, and small tendency of temper brittleness.	Suitable for manufacturing medium and small carburized or carbon nitride infiltration parts with complex stress, high toughness and low strength requirements, such as piston pin, bushing, push rod, small shaft, small gear, gear sleeve, etc.
12crNi3	High-grade carburized steel exhibits excellent comprehensive mechanical properties after quenching with low-temperature or high-temperature tempering. It demonstrates superior low-temperature impact toughness, minimal notch sensitivity, and satisfactory machinability and weldability. However, it is prone to temper brittleness and exhibits high sensitivity to white spots. All carburized steel products require secondary quenching, with cold treatment being necessary in special cases.	Designed for manufacturing various hardened carburized or carburitized parts that require high surface hardness, excellent core mechanical properties, and resistance to heavy loads, impacts, and wear. Typical applications include drive shafts, main shafts, camshafts, mandrels, connecting rods, gears, bushings, pulleys, air valve brackets, oil pump rotors, piston expansion rings, piston pins, universal joint crossheads, critical screws, and adjusting screws.
20crNi3	This steel exhibits excellent comprehensive mechanical properties after quenching and low-temperature tempering, with good low-temperature impact toughness. However, it shows a tendency to form white spots and may develop temper brittleness during high-temperature tempering. When quenched to semi-martensite hardness, it can achieve a depth of penetration of φ50-70mm in oil quenching. The material demonstrates good machinability and moderate weldability.	Mainly used for manufacturing gears, shafts, worms, screws, double-ended bolts, pins, etc. under heavy load conditions.
30crNi3	It has excellent hardenability, high strength and toughness, and good comprehensive mechanical properties after quenching and low temperature tempering or high temperature tempering. It has good machinability, but low plasticity in cold deformation, poor weldability, white spot sensitivity and tendency of temper brittleness. It is generally used in tempered state.	Used for manufacturing large, heavy-load critical components or parts with high thermal forging and stamping loads, such as shafts, worms, connecting rods, crankshafts, drive shafts, steering shafts, front shafts, gears, keys, bolts, nuts, etc.
37crNi3	This material exhibits high toughness and excellent hardenability. When quenched in oil, parts with diameters exceeding φ150mm can achieve full hardenability. It maintains stable creep resistance at 450°C and demonstrates good low-temperature impact toughness. However, during tempering within the 450-550°C range, it develops second-type temper brittleness with a pronounced tendency to form white spots. Due to its exceptional hardenability, normalizing and high-temperature tempering are essential to reduce hardness and improve machinability. The material is typically used in quenched and tempered conditions.	Used for manufacturing heavy-duty, impact, large cross-section parts or low-temperature, impact parts or hot forging, hot stamping parts, such as rotor shaft, impeller, important fasteners, etc
12cr2Ni4	Alloyed carburized steel boasts high strength and toughness with excellent hardenability. After carburizing and quenching, it achieves exceptional surface hardness and wear resistance while maintaining good machinability. The material exhibits moderate plasticity during cold deformation but is susceptible to white spot sensitivity and temper brittleness. Due to poor weldability, preheating is required before welding. Typically, it undergoes carburizing and secondary quenching, followed by low-temperature tempering before use.	After carburizing and secondary quenching and low temperature tempering, it is used to manufacture large carburized parts with heavy load, such as various gears, worm wheels, worm gears, shafts, etc. It can also be used after quenching and low temperature tempering to manufacture mechanical parts with high strength and high toughness.
20cr2Ni4	This material exhibits superior strength, toughness, and hardenability compared to 12cr2Ni4. However, it cannot be directly quenched after carburizing and requires a high-temperature tempering process prior to quenching to reduce residual austenite in the surface layer. It demonstrates moderate cold deformation plasticity and acceptable machinability, though poor weldability necessitates preheating to 150°C before welding. The material shows high sensitivity to white spots and a tendency to develop temper brittleness.	It is used to manufacture large carburized parts with higher performance requirements than 12cr2Ni4, such as large gear shafts and shafts, and can also be used to manufacture tempered parts with high strength and toughness.
20crNiMo	The 20crNiMo steel was originally designated as AISI 8720 in the U.S. AISI and SAE standards. Its hardenability is comparable to 20crNi steel. Although its nickel content is half that of 20crNi steel, the addition of small amounts of molybdenum (Mo) shifts the upper portion of the austenite isothermal transformation curve to the right. Furthermore, by moderately increasing the manganese (Mn) content, this steel maintains excellent hardenability while achieving higher strength than 20crNi steel.	Widely used in manufacturing gears for engines and transmission systems of small and medium-sized automobiles and tractors. It can also replace 12crNi3 steel in producing carburized and cyanide-treated components requiring higher core performance, such as the tooth claws and tooth wheel bodies of toothed drill bits for oil drilling and open-pit mining.
40cr NiMoA	This steel exhibits high strength, toughness, and excellent hardenability. When hardened to half martensite hardness (HRc45), the critical water quenching diameter is ≥100mm, while the critical oil quenching diameter is ≥75mm. At 90% martensite hardness, the critical water quenching diameter ranges from φ80mm to φ90mm, and the critical oil quenching diameter ranges from φ55mm to φ66mm. The steel demonstrates good resistance to overheating but shows high white spot sensitivity and temper brittleness. Its weldability is poor, requiring preheating at high temperatures before welding and stress-relief treatment after welding.	This steel, after heat treatment, is used to manufacture critical components requiring excellent plasticity, high strength, and large dimensions. It is suitable for heavy machinery components such as high-load shafts, steam turbine shafts and blades with diameters over 250mm, high-load transmission parts, fasteners, crankshafts, and gears. Additionally, it can be applied to rotor shafts and blades operating at temperatures exceeding 400°C. Furthermore, this steel can undergo nitriding treatment to produce critical components with specialized performance requirements.
45crNi MoVA	This ultra-high-strength low-alloy steel exhibits excellent hardenability, with a critical hardenability diameter of 60mm in oil (96% martensite). After quenching and tempering, it achieves high strength while maintaining sufficient toughness and machinability. However, its cold deformation plasticity and weldability are limited. The material demonstrates poor corrosion resistance and requires moderate operating temperatures due to its sensitivity to tempering conditions. Typically, it is used after quenching and low-temperature (or medium-temperature) tempering.	Primarily used to manufacture high-strength structural components such as aircraft engine crankshafts, beams, landing gear, pressure vessels, and casings for small and medium-sized rockets. In heavy machinery manufacturing, it is employed to produce heavy-duty load-bearing components including torque shafts, gearbox shafts, and friction clutch shafts.
18cr2Ni4W	The mechanical properties are better than 12cr2Ni4 steel, and the processing properties are similar to 12cr2Ni4 steel	Used for parts with larger cross-sections and higher performance requirements than 12cr2Ni4 steel
25cr2N i4WA	Good comprehensive performance and high working temperature resistance	Manufacturing important parts that work under dynamic loads, such as excavator shaft gears

 （五）Free-cutting  steel (GB/T 8731-1988)

(1) Mechanical properties of machinable structural steel (see Table 3-1-13)

Table 3-1-13 Mechanical properties of machinable structural steel

the name of a shop	Hot rolled bar and wire rod				Cold rolled strip steel
	Tensile strength σb/Mpa	Extension rate δ5 (%)	contraction percentage ψ（%）	Brinell hardness HBS ≤	Tensile strength σbMpa			Extension rate δ5 (%) ≥	Brinell hardness HBS ≤
		≥			Steel bar size (mm)
					8 ~ 20	> 20 ~ 30	> 30
Y12 Y12pb Y15 Y15pb	390 ~ 540	22	36	170	530 ~ 755	510 ~ 735	490 ~ 685	7 .0	152 ~ 217
Y20	450 ~ 600	20	30	175	570 ~ 785	530 ~ 745	510 ~ 705		167 ~ 217
Y30	510 ~ 655	15	25	187	600 ~ 825	560 ~ 765	540 ~ 735	6 .0	174 ~ 223
Y35		14	22		625 ~ 845	590 ~ 785	570 ~ 765		176 ~ 229
Y40Mn	590 ~ 735		20	207	590 ~ 785		590 ~ 785	17	179 ~ 229
Y45ca	600 ~ 745	12	26	241	695 ~ 920	655 ~ 855	635 ~ 835	6 .0	196 ~ 255

(2) Characteristics and applications of machinable structural steel (see Table 3-1-14)

Table 3-1-14 Characteristics and applications of machinable structural steels

the name of a shop	Features and Examples
Y12 Y15	Used in the manufacture of mechanical screws, rods, nuts, bolts for connecting parts, steering tie rod ball bolts, oil pump drive gears, etc.
Y12pb Y15pb	Fasteners and standard parts for automatic machining, such as nuts, pipe fittings, pins, and small shafts.
Y20	Used to make parts with complex cross-sections that are difficult to process on small machines such as sewing machines, typewriters, and computers, as well as pins for internal combustion engine camshaft, clutch switch, and spherical chuck head.
Y30 Y35	Components requiring higher tensile strength are typically used in cold-drawn condition
Y40Mn Y45ca	Used to manufacture heat-treated gears, shafts, etc

（六）Non-quenched and tempered mechanical structural steel(GB/T 15712-1995)

Non-quenched and tempered mechanical structural steelis a new energy-saving steel type obtained by adding trace alloy elements to medium carbon steel and controlling temperature rolling (forging) and cooling, so that the mechanical properties of carbon structural steel or alloy structural steel can be achieved after tempered treatment without tempered treatment after rolling (forging).

Non-quenched and tempered mechanical structural steel, widely used in automobile, machine tool and agricultural machinery.

The mechanical properties of Non-quenched and tempered mechanical structural steel grades are shown in Table 3-1-15.

Table 3-1-15Non-quenched and tempered mechanical structural steel grades and mechanical properties

Steel type	the name of a shop	Tensile strength σb/Mpa	yield point σ5 Mpa	Extension rate δ5 (%)	contraction percentage ψ（%）	Impact absorption power Ak/J	Brinell hardness HBS ≤
		≥
Easy to cut and non-adjustable, with a diameter or side length ≤ 40mm steel	YF35v	590	390	18	40	47	229
	YF40v	640	420	16	35	37	255
	YF45v	685	440	15	30	35	257
	YF35Mnv	735	460	17	35	37	257
	YF40Mnv	785	490	15	33	32	275
	YF45Mnv	835	510	13	28	28	285
Steel with a diameter or side length of 40-60mm is easy to cut and non-toughened.	YF35Mnv	710	440	15	33	35	257
	YF40Mnv	760	470	13	30	28	265
	YF45Mnv	810	490	12	28	25	275
Hot-dip galvanizing with non-machined steel	F45v	685	440	15	40	32	257
	F35MnvN	785	490	15	40	39	269
	F40Mnv	785	490	15	40	36	275

(七)  Spring  steel (GB/T 1222-1984)

(1) Mechanical properties of spring steel (see Table 3-1-16) Table 3-1-16 Mechanical properties of spring steel

the name of a shop	heat treating regime			mechanical property ≥
	hardening temperature /℃	quenching agent	temperature /℃	yield point σs	tensile strength σb	elongation （%）		section Shrinkage rate ψ (%)
				Mpa		δ5	δ10
65	840	oil	500	784	980		9	35
70	830	oil	480	833	1029		8	30
85	820	oil	480	980	1127		6	30
65Mn	830	oil	540	784	980		8	30
555i2Mn	870	oil	480	1176	1274		6	30
555i2MnB	870	oil	480	1176	1274		6	30
555iMnvB	860	oil	460	1225	1372		5	30
605i2Mn	870	oil	480	1176	1274		5	25
605i2MnA	870	oil	440	1372	1568		5	20
605i2crA	870	oil	420	1568	1764	6		20
605i2crvA	850	oil	410	1666	1862	6		20
55crMnA	830 ~ 860	oil	460 ~ 510	1078 (σ0 .2）	1225		9	20
60crMnA	830 ~ 860	oil	460 ~ 520	1078 (σ0 .2）	1225		9	20
60crMnMOA	-	-	-	-	-	-		-
50crvA	850	oil	500	1127	1274	10		40
60crMnBA	830 ~ 860	oil	460 ~ 520	1078 (σ0 .2）	1225	9		20
30W4cr2vA	1050 ~ 1100	oil	600	1323	1470	7		40

(2) Characteristics and applications of spring steel (see Table 3-1-17)

Table 3-1-17 Characteristics and applications of spring steel

the name of a shop	Main Features	Use examples
65 70 85	It can obtain high strength, hardness and flexural strength ratio, but the hardenability is small, the heat resistance is not good, and the ability to withstand dynamic load and fatigue load is low	It is widely used, but mostly for small springs with low working temperature or large springs that are not important. For example, springs used in automobiles, tractors, railway vehicles and general machinery.
65Mn	The composition is simple, and the quenching and hardening properties, comprehensive mechanical properties, decarburization and other process properties are better than carbon steel, but it is sensitive to overheating, has temper brittleness, and is prone to crack after quenching	Low cost and high volume. It can be used to manufacture various small cross-section flat springs, round springs, springs, etc., as well as valve springs, spring rings, shock absorbers, clutch spring blades, brake springs, etc.
55S,2Mn 60S,2Mn 60S,2MnA	The silicon content (wS) is high (up to 2.00%), with high strength and good elasticity. It exhibits excellent resistance to tempering. However, it is prone to decarburization and graphitization, and has limited hardenability.	The main types of spring steel are widely used in the manufacture of various springs, such as plate springs for automobiles, locomotives and tractors, helical springs, cylinder safety valve springs and some important springs working under high stress, and severely worn springs.
55S,2MnB	Because of boron, its hardenability is significantly improved	Front and rear suspension springs and auxiliary springs for light and medium vehicles
55S,MnvB	The steel grade independently developed in China outperforms 60S and 2Mn steel in hardenability, comprehensive mechanical properties, and fatigue resistance.	It mainly produces plate springs for medium and small cars with good performance, and can also produce other plate springs and helical springs with medium cross section size
60S,2crA 60S,2crvA	High-strength spring steel with excellent hardenability and superior heat treatment performance. Due to its high strength, the spring should be promptly treated after coiling to relieve internal stresses.	Manufacturing high-capacity spring components for critical applications. The 60S,2crA grade steel is used to produce steam turbine sealing springs, adjustment springs, condenser support springs, and high-pressure pump disc springs. Additionally, this grade is employed in manufacturing critical components such as conventional weapon ammunition retrieval hooks and crusher springs.
55crMnA 60crMnA	The outstanding advantages are good hardenability, good hot workability, good comprehensive mechanical properties and good decarburization resistance	Various important springs with large cross-sections, such as large plate springs and helical springs for automobiles and locomotives
60crMnMOA	Among the various spring steels available, this one exhibits the highest degree of hardenability, along with superior mechanical properties and excellent temper stability.	Ultra-large springs for heavy-duty construction equipment, vehicles, and machinery. The steel plates can be over 35mm thick, and the round steel bars can exceed 60mm in diameter.
50crvA	A small amount of vanadium improves the spring's elasticity, strength, yield strength ratio, and elastic deformation resistance, refines the grain size, and reduces the tendency to decarburize. With a low carbon content, it exhibits better plasticity and toughness than other spring steels. It also has high hardenability and good fatigue performance.	Various important helical springs are especially suitable for spring with high working stress amplitude and strict fatigue performance requirements, such as valve spring, injector spring, cylinder expansion ring, safety valve spring, etc
60crMnBA	The permeability is higher than 60crMnA, and other properties are similar	Larger plate springs, helical springs, torsion springs, etc
30W4Cr2VA	High strength heat-resistant spring steel with excellent hardenability and good high temperature creep resistance and hot working properties.	Heat-resistant springs for applications below 500°C, including turbine main steam valve springs, steam seal spring sheets, boiler safety valve springs, and 400-ton boiler disc valve springs.

（二）Tool steel

(一) Carbon Tool Steel (GB/T 1298-1986)

(1) Carbon tool steel grade, chemical composition, and hardened steel hardness (see Table 3-1-18)

Table 3-1-18: Carbon Tool Steel Grades, Chemical Composition, and Hardness of the Steel After Quenching

the name of a shop	Chemical composition (mass fraction)%					Annealed steel hardness HBS ≤	Hardness of steel after quenching
	C	Mn	Si ≤	S ≤	P ≤		Hardening temperature /℃ and coolant	HRC ≥
T7	0 .65 ~ 0 .74	≤0 .40	0 . 35	0 .030	0 .035	187	800 to 820 water	62
T8	0 .75 ~ 0 . 84						780 to 800 water
T8Mn	0 . 80 ~ 0 .90	0 .40 ~ 0 .60
T9	0 . 85 ~ 0 .94	≤0 .40				192	760 to 780 water
T10	0 .95 ~ 1 .04					197
T11	1 .05 ~ 1 . 14					207
T12	1 . 15 ~ 1 .24
T13	1 .25 ~ 1 . 35					217

(2) Characteristics and Applications of Carbon Tool Steel (see Table 3-1-19)

Table 3-1-19 Characteristics and applications of carbon tool steel

the name of a shop	key property	Example
T7 T7A	Steel with eutectoid composition. Its strength increases with the increase of carbon content, and it has a good combination of strength and plasticity, but the cutting ability is poor	Designed for tools requiring high plasticity and hardness with moderate cutting performance. Common applications include chisels, punches, small pneumatic tools, woodworking tools (saws, chisels, forging dies, press dies), hand tools (pliers, hammers, rivet punches), mallets, lathe centers, sheet metal shears, and drill bits.
T8 T8A	Steel belonging to the eutectoid composition is prone to overheating during quenching, exhibits significant deformation, and has low strength and plasticity, making it unsuitable for tools subjected to heavy impact. However, after heat treatment, it achieves high hardness and wear resistance.	Tools designed to operate without overheating during use, such as milling cutters for wood processing, countersunk drills, axes, chisels, simple mold punches, hand saws, circular saw blades, rollers, lead-tin alloy die-cast plates and cores, fitting tools, and pneumatic tools.
T8Mn T8MnA	The performance is comparable to T8 and TSA, but it has higher hardenability and can achieve a deeper hardened layer. It can be used for tools with larger cross-sections.	In addition to manufacturing tools compatible with T8 and T8A standards, it can also produce crosshair files, hand saw blades, coal mining tools, and stone chisels.
T9 T9A	Performance comparable to T8 and T8A	It is used to make tools with toughness and hardness, such as punch and woodwork tools. T9 can also be used to make cutting parts for agricultural machinery, such as blades.
T10 T10A	It is a hypereutectoid steel that can maintain fine grains at 700 ~ 800℃ without overheating. After quenching, the steel contains insoluble excess carbides, which increase the wear resistance of the steel. It is suitable for manufacturing tools that do not change heat during work.	Manufacture hand saw, machine fine saw, twist drill, wire drawing fine film, small punch die, tap, turning and planing tool, hole expanding tool, thread plate, milling cutter, drill bit for hard rock, thread tool, drill tool for tight rock, chisel for engraving and filing, etc.
T11 T11A	In addition to the characteristics of T10 and T10A, it also has good comprehensive mechanical properties, such as hardness, wear resistance and toughness. It is less sensitive to grain growth and the formation of carbide network.	Tools that are not easily heated during manufacturing, such as taps, files, scrapers, small-sized cold stamping dies with no abrupt changes in cross-section, and woodworking tools.
T12 T12A	High in carbon content, there is more excess carbide after quenching, so the wear resistance and hardness are high, but the toughness is low, suitable for the manufacture of impact-free, but need very high hardness of tools	Suitable for manufacturing tools with low speed and easy to avoid heat, such as turning tools, milling tools, drills, reamers, hole expanders, taps, plate cutters, scrapers, gauges, and small cross-section cold cutting edge molds, punching molds, metal saw blades, copper tools, etc.
T13 T13A	It is the steel with the highest carbon content in carbon tool steel. It has extremely high hardness, increased carbide and uneven distribution, and low mechanical properties. It can not withstand impact and can only be used as a tool for cutting high hardness materials.	Used for manufacturing razors, cutting tools, turning tools, engraving tools, scrapers, wire drawing tools, drill bits, tools for hard stone processing, and carving tools.

(二) Alloy tool steel (GB/T 1299-2000)

(1) Alloy tool steel grade and quenching hardness value (see Table 3-1-20)

Table 3-1-20 Alloy Tool Steel Grades and Quenching Hardness Values

order number		the name of a shop	Delivery Status		Sample Test
			Brinell hardness HBS	impression diameter /mm	Hardening temperature/℃ and coolant		Rockwell hardness HRC ≥
1 - 1		9SiCr	241 ~ 197	3 .9 ~ 4 . 3	820 to 860, oil		62
1 - 2		8MnSi	≤229	≥4 .0	800 to 820, oil		60
	1 - 3	cr06	241 ~ 187	3 .9 ~ 4 .4		780 ~ 810, water	64
	1 - 4	cr2	229 ~ 179	4 .0 ~ 4 .5		830 ~ 860, oil	62
	1 - 5	9cr2	217 ~ 179	4 . 1 ~ 4 .5		820 to 850, oil	62
	1 - 6	W	229 ~ 187	4 .0 ~ 4 .4		800 to 830, water	62
	2 - 1	4crW2si	217 ~ 179	4 . 1 ~ 4 .5		860 ~ 900, oil	53
	2 - 2	5crW2si	255 ~ 207	3 . 8 ~ 4 .2		860 ~ 900, oil	55
	2 - 3	6crW2si	285 ~ 229	3 .6 ~ 4 .0		860 ~ 900, oil	57
	3 - 1	cr12	269 ~ 217	3 .7 ~ 4 . 1		950 to 1000, oil	60
	3 - 2	cr12Mo1V1	≤255	≥3 . 8		①	59
	3 - 3	cr12MoV	255 ~ 207	3 . 8 ~ 4 .2		950 to 1000, oil	58
	3 - 4	crsMo1V	≤255	≥3 .95		②	60
	3 - 5	9Mn2V	≤229	≥4 .0		780 ~ 810, oil	62
	3 - 6	crWMn	255 ~ 207	3 . 8 ~ 4 .2		800 to 830, oil	62
	3 - 7	9crWMn	241 ~ 197	3 .9 ~ 4 . 3		800 to 830, oil	62
	3 - 8	crW2MoV	≤269	≥3 .7		960 ~ 980、 1020 to 1040, oil	60
	3 - 9	6cr4W3          -          - Mo2VNb	≤255	≥3 . 8		1100 to 1160, oil	60
	3 - 10	6W6Mo5cr4V	≤269	≥3 .7		1180 to 1160, oil	60
	4 - 1	5crMnMo	241 ~ 197	3 .9 ~ 4 . 3		820 to 850, oil	60
	4 - 2	5crMiMo				830 ~ 860, oil
	4 - 3	3cr2W8V	255 ~ 207	3 . 8 ~ 4 .2		1075 ~ 1125, oil	60
	4 - 4	5c r4Mo3 - siMnVAI	255	≥3 . 8		1090 ~ 1120, oil	60
	4 - 5	3cr3Mo3W2V				1060 ~ 1130, oil
	4 - 6	5cr4W5Mo2V	≤269	≥3 .7		1100 to 1150, oil	60
	4 - 7	8cr3	255 ~ 207	3 . 8 ~ 4 .2		850 ~ 880, oil	60
	4 - 8	4crMnsiMoV	241 ~ 197	3 .9 ~ 4 . 3		870 ~ 930, oil	60
	4 - 9	4cr3Mo3siV	≤229	≥4 .0		③	60
	4 - 10	4cr5MosiV	≤235	≥3 .95		④	60

4 - 11	4cr5Mosiv1	≤235	≥3 .95	⑤	60
4 - 12	4cr5W2vsi	≤229	≥4 .0	1030 ~ 1050, oil or air	60
5 - 1	7Mn15cr - 2Al3v2WMo	-	-	1170 ~ 1190, solid solution water 650 ~ 700, time-out	45
6 - 1	3cr2Mo	-	-		-

(2) Properties and applications of alloy tool steel (see Table 3-1-21)

Table 3-1-21 Properties and applications of alloy tool steel

the name of a shop	Main Features	Use examples
9sicr	The hardenability is better than chromium steel. The workpiece of φ45mm ~ φ50mm can be hardened in oil, with high wear resistance and good temper stability. The cutting ability is poor, and the deformation is small during heat treatment, but the tendency of decarburization is large.	Suitable for cutting tools with high wear resistance, low cutting force and small deformation, such as plate cutters, taps, drills, reamers, gear milling cutters, draw tools, etc. It can also be used as cold stamping dies and cold rolling rolls
8Mnsi	Resilience, hardenability and wear resistance are better than carbon tool steel	It is widely used as a wood chisel, saw blade, and other tools. It is also used to manufacture perforating and enlarging tools, small-sized hot forging dies and punches, hot pressing dies, bolts, track nail punches, wire drawing dies, cold stamping dies, and cutting tools.
cr06	After quenching, the hardness and wear resistance are very high, but the hardenability is not good and the toughness is relatively brittle	After being cold rolled into thin steel strip, it is used to make razors, blades and surgical tools, and can also be used as scrapers, engraving knives, files and so on.
cr2	After quenching, the hardness and wear resistance are very high, the deformation of quenching is not large, but the high temperature plasticity is poor	It is mainly used for low speed, small feed, and machining materials not very hard cutting tools, such as turning tools, cutting tools, milling tools, reamers, etc. It can also be used as measuring tools, templates, gauges, eccentric wheels, cold rolling rollers, drill sleeves and wire drawing dies, and can also be used as large size cold stamping dies
9cr2	Performance is similar to that of CR2	Primarily used for cold rolling mills, steel stamp punch tools, cold stamping dies and punches, and woodworking tools.
w	The hardness and wear resistance after quenching are better than carbon steel, the deformation after heat treatment is small, and the water quenching is not easy to crack	It is mainly used for tools with low working temperature and low cutting speed, such as small twist drills, taps, plate teeth, reamers, saw blades, roller tools, etc.
4crw2si	It has good strength and hardness at high temperature, and high toughness	Suitable for shear blade, pneumatic tools with high impact vibration, medium stress hot forging die, and low heat cast die
5crw2si	It shares the same properties as 4crw2si, but exhibits slightly higher hardness at 650°C, reaching approximately 41-43 HRc. During heat treatment, it demonstrates minimal sensitivity to decarburization, deformation, and cracking.	Suitable for manual and pneumatic chisels, air hammer tools, riveting tools, cold stamping dies, and heavy vibration cutting tools. When used for hot work steel, it can also be applied to punching and piercing tools, shearing dies, hot forging dies, and die-casting dies for fusible alloys.
6crw2si	It shares the same properties as 5crw2si, yet achieves a hardness of 43 to 45 HRc at 650°C.	Suitable for stamping dies, pressing dies, casting finishing tools, pneumatic chisels, etc. under heavy loads. As a hot working steel, it can be used to produce screw and hot rivet punch, high temperature die casting light alloy top head, hot forging die, etc.
cr12	High carbon and high chromium steel has high strength, wear resistance and hardenability, small deformation after quenching, brittle, poor thermal conductivity and poor plasticity at high temperature	It is mainly used in the manufacture of molds with high wear resistance and no impact, and cutting tools with non-hard processing materials, such as turning tools, reamers, cold stamping dies, punches, gauges, templates, measuring tools, cam pins, eccentric wheels, cold rolling rolls, drill sleeves and wire drawing dies.
cr12MoV	The workpiece has higher hardenability, hardness, strength and toughness after quenching and tempering than CR12. The workpiece with a cross section of less than 300 ~ 400mm can be fully hardened, and the wear resistance and plasticity are better, with small deformation, but the high temperature plasticity is poor.	Suitable for various casting, forging, and mold applications, including punching dies, trimming dies, edge rolling dies, seam dies, wire drawing dies, steel plate drawing dies, thread forming plates, standard tools, and measuring instruments.
cr5Mo1V	This steel grade, imported from the United States, exhibits excellent air quenchability with minimal deformation during quenching. Its toughness surpasses both 9Mn2V and Cr12, featuring uniformly distributed fine carbides and superior wear resistance.	Suitable for manufacturing cold working dies, forming dies, cutting dies, punches, cold blanking dies, etc. with good toughness and wear resistance
9Mn2V	Hardness and wear resistance are higher than carbon steel, and deformation is small after quenching	Suitable for making various small deformation, high wear resistance precision screw, grinding machine spindle, template, cam, gauge block, gauge tool and tap, plate, reamer and die casting light metal and alloy push-in device
crwMn	The material exhibits superior hardenability and wear resistance, with higher hardness than chromium steel and chromium-silicon steel, along with better toughness. It also demonstrates less deformation after quenching compared to CRMn steel. However, its drawback lies in the severe formation of carbide networks.	It is mainly used to manufacture cutting tools with small deformation, long and complex shape, such as reamers, long taps, long reamers, special milling tools, gauges and cold stamping dies with complex shape and high precision
9crwMn	Similar to crwMn, it exhibits superior carbide segregation due to its slightly lower carbon content, resulting in better mechanical properties, though its hardness remains relatively low after heat treatment.	same crwMn
cr4w2MoV	This is a new type of medium alloy cold working die steel independently developed in China. It has fine and uniform distribution of eutectic compound particles, high hardenability and hardenability, and good mechanical properties, wear resistance and dimensional stability.	Suitable for manufacturing cold stamping dies, cold extrusion dies, and threading dies, and can also perform punching on spring steel plates with thicknesses ranging from 1.5 to 6.0 mm.
6cr4w - 3Mo2VNb	High toughness cold working die steel, with high strength, high hardness, good toughness, and high fatigue strength	For manufacturing cold working dies, cold extrusion dies, cold heading dies, and screw punches with complex shapes under impact loads.
6w6Mo - 5cr4V	It is a mold steel developed by China for extrusion of ferrous metals, with high strength, high hardness, wear resistance and stability against tempering, and good comprehensive properties.	Suitable for punches and molds
5crMnMo	Hammer forging die steel without nickel has good toughness, strength and high wear resistance, and is not sensitive to temper brittleness and has good hardenability	Suitable for medium and small hot forging with side lengths of 300 to 400 mm or less.
5crNiMo	Similar to 5crMnMo, it exhibits superior high-temperature strength, toughness, and resistance to thermal fatigue.	Suitable for medium and large hammer forging dies with complex shapes and strong impact loads
3cr2w8V	Commonly used die-casting mold steels feature low carbon content to ensure high toughness and excellent thermal conductivity. These steels contain abundant chromium and tungsten, which readily form carbides. They exhibit high hardness and strength at elevated temperatures, possess a high phase transformation temperature, demonstrate superior heat fatigue resistance, and exhibit good hardenability. When the cross-sectional thickness is ≤100mm, they can achieve full hardenability, though their toughness and plasticity remain relatively limited.	Suitable for high temperature and high stress but not impact pressing dies, such as convex and concave dies, inlay blocks, copper alloy extrusion dies on flat forging machines, etc., can also be used as hot shear knives
5cr4Mo - 3siMnVAl	It has high toughness, good heat resistance and cold and hot fatigue, and good hardenability and hardening. It is a hot working die steel and can also be used as a cold working die steel.	Ideal for manufacturing cold heading dies, punching dies, hot forging dies for groove bolts, and hot extrusion punches, it can replace 3cr2W8V and cr12MoV.
3cr3Mo 3W2V	It has good cold and hot working properties, high thermal strength, good cold and hot fatigue resistance, good wear resistance, good hardening properties, and certain impact resistance	Hot working dies can be produced, such as forging dies, precision forging dies, rolling dies, and press dies.
5cr4W 5Mo2V	It is a kind of hot extrusion and precision forging die steel developed by China, which has high heat hardness, high wear resistance, high temperature strength, anti-tempering stability and certain impact toughness. It can be subjected to general heat treatment or isothermal heat treatment and chemical heat treatment.	Primarily used for manufacturing hot extrusion dies, often replacing 3cr2W8V.
8cr3	It has good hardenability, both room temperature strength and high temperature strength, fine and evenly distributed carbides, and good wear resistance	It is commonly used in molds with low impact and vibration, working temperature below 500℃, and wear resistance, such as hot cutting edge mold, forming punch mold, bolt hot top forging mold, etc.
4crMnsiMoV	It exhibits superior high-temperature mechanical properties and excellent thermal fatigue resistance, making it a viable replacement for 5crNiMo.	Used for manufacturing hammer forging dies, press forging dies, correction dies, bending dies, and other types of dies.
4cr3Mo3siV	With high hardenability, high temperature hardness, and excellent toughness, it can replace 3cr2WBV.	Can make hot rolling die, plastic die, hot forging die, hot stamping die, etc
4cr5MosiV	It has high hardenability, good comprehensive properties below medium temperature, small deformation of heat treatment, and good cold and hot fatigue resistance	Ideal for manufacturing hot extrusion dies, bolt dies, hot cutting dies, hammer forging dies, and aluminum alloy die-casting dies.
4cr5MosiV1	It demonstrates excellent comprehensive performance at medium temperatures (≈600°C), featuring high hardenability (achieving hardness in air), minimal deformation during heat treatment, and superior performance with extended service life compared to 3cr2W8V.	Suitable for forging hammer dies, aluminum alloy die casting molds, hot extrusion dies, high-speed precision forging dies, and forging press dies.
4cr5W2Vsi	At medium temperature, it has high hardness and thermal strength, good toughness and wear resistance, and good cold and hot fatigue resistance	Suitable for forging dies, punches, hot extrusion dies, and die casting molds for non-ferrous metals.
7Mn15cr2 Al3V2WMo	The austenite can be maintained in various states, and has very low permeability, high strength, hardness, wear resistance, but poor cutting performance	Used to manufacture non-magnetic molds, non-magnetic bearings and structural parts that do not produce magnetic induction in strong magnetic fields
3cr2Mo	It has good cutting performance and mirror grinding performance. After mechanical processing, the cavity deformation and dimensional change are small. After heat treatment, the surface hardness can be improved and the service life can be improved.	Suitable for manufacturing plastic molds and low-melting metal die-casting molds

（三）High-speed tool steel (GB/T 9943-1988)

（1）High-speed tool steel grades and quenching hardness (see Table 3-1-22)

Table 3-1-22 High-speed tool steel grades and quenching hardness

the name of a shop	Hardness at delivery HBS ≤		Test sample heat treatment system and quenching and tempering hardness
	Other processing methods	anneal	preheat temperature /℃	hardening temperature /℃		quenching agent	temperature /℃	HRc ≥
				salt bath furn	box furnace
W18cr4V	269	255	820 ~ 870	1270 ~ 1285	1270 ~ 1285	oil	550 ~ 570	63
W18cr4Vco5	285	269	820 ~ 870	1270 ~ 1290	1280 ~ 1300	oil	540 ~ 560	63
W18cr4V2co8	302	285	820 ~ 870	1270 ~ 1290	1280 ~ 1300	oil	540 ~ 560	63
W12cr4V5co5	293	277	820 ~ 870	1220 ~ 1240	1230 ~ 1250	oil	530 ~ 550	65
W6Mo5cr4V2	262	255	730 ~ 840	1210 ~ 1230	1210 ~ 1230	oil	540 ~ 560	63 （ box furnace ）
								64 （ salt bath furn ）
cW6Mo5cr4V2	269	255	730 ~ 840	1190 ~ 1210	1200 ~ 1220	oil	540 ~ 560	65
W6Mo5cr4V3	269	255	730 ~ 840	1190 ~ 1210	1200 ~ 1220	oil	540 ~ 560	64
cW6Mo5cr4V3	269	255	730 ~ 840	1190 ~ 1210	1200 ~ 1220	oil	540 ~ 560	64
W2Mo9cr4V2	269	255	730 ~ 840	1190 ~ 1210	1200 ~ 1220	oil	540 ~ 560	65
W6Mo5cr 4V2co5	285	269	730 ~ 840	1190 ~ 1216	1200 ~ 1220	oil	540 ~ 560	64
W7Mo4cr 4V2co5	285	269	730 ~ 840	1180 ~ 1200	1190 ~ 1210	oil	530 ~ 550	66
W2Mo9cr 4Vco8	285	269	730 ~ 840	1170 ~ 1190	1180 ~ 1200	oil	530 ~ 550	66
W9Mo3cr4V	269	255	820 ~ 870	1210 ~ 1230	1220 ~ 1240	oil	540 ~ 560	63 （ box furnace ）
								64 (Salt furnace)
W6Mo5cr 4V2A1	285	269	820 ~ 870	1230 ~ 1240	1230 ~ 1240	oil	540 ~ 560	65

(2) Characteristics and applications of high-speed tool steel (see Table 3-1-23)

Table 3-1-23 Characteristics and applications of high-speed tool steel

the name of a shop	Main Features	Use examples
W18cr4V	This material exhibits excellent high-temperature hardness, maintaining superior hardness and cutting performance even at 600°C. It demonstrates good machinability, low overheating sensitivity during quenching, and superior heat resistance compared to alloy tool steels. However, its coarse carbide structure leads to reduced strength and toughness as material dimensions increase. Therefore, it is only suitable for manufacturing general-purpose tools, not thin-edge or large-scale cutting tools.	It is widely used in the manufacturing of various tools for medium or soft materials, such as turning tools, milling tools, drawing tools, gear tools, taps, etc.; it can also be used to make cold working molds, and can also be used to manufacture bearings, springs and other wear-resistant and high-temperature parts that work under high temperature.
W18cr4 Vco5	Cobalt-containing high-speed steel exhibits excellent high-temperature hardness and heat hardenability, along with superior wear resistance. It achieves high quenching hardness, with surface hardness reaching 64 to 66 HRc.	It can manufacture and process various tools for high-speed cutting with high hardness, such as hobbing tools, turning tools and milling tools, as well as machining tools for automated machine tools
W18cr 4V2co8	Cobalt-containing high-speed steel outperforms W18cr4VcO5 in high-temperature hardness and wear resistance, though with reduced toughness. Its quenched hardness reaches 64-66 HRc (surface hardness).	It can be used to manufacture and process various tools with high hardness and high cutting force, such as milling cutter, roller cutter and turning cutter
W12cr 4V5co5	High carbon, high vanadium and cobalt high speed steel has good wear resistance, high hardness, good stability against tempering and high hardness at high temperature. Therefore, the working temperature is high and the working life is several times higher than other high speed steel.	Suitable for machining difficult materials, such as high strength steel, medium strength steel, cold rolled steel, cast alloy steel, etc., suitable for making turning tools, milling tools, gear tools, forming tools, thread machining tools and cold working molds, but not suitable for manufacturing high precision complex tools
W6Mo5 cr4V2	This high-speed tool steel exhibits excellent high-temperature hardness and toughness, with surface hardness reaching 64-66 HRc after quenching. Containing molybdenum and low tungsten, it is cost-effective and widely used, second only to W18cr4V in popularity.	Suitable for manufacturing drills, taps, broaches, milling cutters, gear tools, cold working dies, etc.
cW6Mo5 cr4V2	After quenching, the surface hardness, high-temperature hardness, heat resistance, and wear resistance are all improved compared to W6Mo5cr4V2, but its strength and impact toughness are reduced.	Used to manufacture tools with high cutting performance and low impact, such as reamers, hedges, lathes, and hole expanders
W6Mo5 cr4V3	It features fine and uniform carbides, high toughness, and good plasticity. Its wear resistance surpasses W6Mo5cr4V2, but it has poor grindability and is prone to oxidation and decarburization.	It can be used to make various types of general tools, such as turning tools, planers, taps, drills, forming milling tools, drawing tools, rolling tools, thread combs, etc., which are suitable for machining medium and high strength steel, high temperature alloys and other difficult to process materials. Because of the poor grinding properties, it is not suitable for making high precision and complex tools.
cW6Mo   - 5cr4V3	High-carbon molybdenum high-speed steel is a steel grade developed from W6Mo5cr4V3 by increasing the average carbon content (wc) from 1.05% to 1.20% and correspondingly raising the vanadium content, thereby enhancing its wear resistance.	Same as W6Mo5cr4V3
W2Mo9 cr4V2	It has high temperature hardness, toughness and wear resistance, low density and good grindability, and has good effect when cutting general materials	For manufacturing milling cutters, forming tools, taps, saw blades, turning tools, broaches, cold stamping dies, and other specialized tools.
W6Mo5cr - 4V2co5	Cobalt-containing high-speed steel has good high-temperature hardness, good cutting performance and wear resistance, but low strength and impact toughness	A variety of tools can be used to manufacture and process hard materials, such as gear tools, milling tools, punches, etc
W7Mo4cr 4V2co5	The W6Mo5cr4v2 steel has been enhanced with 5% cobalt (wco), increased carbon content, and optimized tungsten and molybdenum levels. This upgrade improves high-temperature hardness and wear resistance, while maintaining good machinability. However, the steel's strength and impact toughness remain relatively low.	Generally used in the manufacture of gear tools, milling tools, punches, tool heads and other tools for cutting hard materials
W2Mo9 cr4Vco8	High carbon cobalt superhard high speed steel, with high room temperature hardness and high temperature hardness, good grinding properties, sharp blade	It is suitable for making various high-precision and complex tools, such as forming milling tools, precision drawing tools, special drills, turning tools, tool heads and blades. For processing difficult-to-process materials such as casting high-temperature alloys, titanium alloys and ultra-high strength steel, it can get good results.
W9Mo3 cr4V	A tungsten-molybdenum alloy general-purpose high-speed steel with strong versatility, outperforming W6Mo5cr4V2 in comprehensive performance while maintaining lower costs.	Manufacture a variety of high speed cutting tools and cold and hot molds
W6Mo5 - cr4V2Al	Aluminum-containing superhard high-speed steel, with high high-temperature hardness, high wear resistance, good thermal plasticity, long working life	Suitable for machining various difficult materials, such as high temperature alloy, ultra-high strength steel, stainless steel, etc., can be made of turning tools, boring tools, milling tools, drill bits, gear tools, drawing tools, etc

（三） Bearing steel

The characteristics and applications of common bearing steel grades are shown in Table 3-1-24.

Table 3-1-24 Characteristics and applications of commonly used bearing steel grades

(1) High-carbon chromium stainless bearing steel (GB/T 3086-1982)

the name of a shop	Main Features	Use examples
9cr18 9cr18Mo	It has high hardness and high temper stability, good cutting performance and cold stamping properties, and poor thermal conductivity. It has higher mechanical properties after quenching, cold treatment and low temperature tempering.	This material is used to manufacture corrosion-resistant bearing rings and rolling elements for applications in seawater, river water, nitric acid, chemical and petroleum industries, as well as nuclear reactor applications. It can also be used to produce high-temperature resistant bearing steel with a maximum operating temperature of 250°C. Additionally, it is suitable for manufacturing high-quality tools, medical surgical knives, and mechanical components that require wear and corrosion resistance while handling relatively low dynamic loads.

(2) High carbon chromium bearing steel

the name of a shop	Main Features	Use examples
Gcr9	It has high wear resistance and hardenability, medium cutting performance and strain plasticity, sensitive to white spot formation, poor weldability, and tendency to temper brittleness. It is mainly used in quenched and low-temperature tempered state.	This bearing steel is widely used to manufacture small steel balls and rollers for rotating shafts, large bushings and rolling elements for general working conditions. It is commonly applied in micro bearings and general bearings for machine tools, locomotives, motors, and aviation. Additionally, it can be used to produce critical mechanical components that require high elasticity, wear resistance, and contact fatigue strength.
Gcr15	It has good hardenability, high wear resistance, high fatigue life, medium plastic deformation in cold working, certain cutting properties, and poor weldability. It is generally used after quenching and low-temperature tempering.	Steel balls, rollers and rings are used to manufacture large mechanical bearings. They can also be used to manufacture machine parts with large load, such as toothed wheel drill bit rotating shaft, blade, pump stator, mold, sleeve, spindle, machine tool screw rod, cold stamping mold, etc.
Gcr9	The performance is comparable to Gcr15, but the hardenability and processing	Designed for manufacturing larger bearing sleeves, it can replace Gcr15.
siMn	Higher performance	make use of
Gcr15 siMn	It has higher wear resistance and hardenability than Gcr15, moderate cold workability, poor weldability, sensitivity to white spot formation, and temper brittleness during heat treatment.	Designed for manufacturing large bearing components such as rings, steel balls, and rollers, it also produces high-wear-resistant, high-hardness parts including rolls and gauges, with properties and applications comparable to Gcr15.

(3) Carburized bearing steel (GB/T3203-1982)

the name of a shop	Example
G20crMo	Used in bearings for automobiles, tractors, and other equipment subjected to impact loads, including raceways and rolling elements.
G20crNiMo	Used in bearings for automobiles, tractors, and other equipment subjected to impact loads, including raceways and rolling elements.
G20crNi2Mo	Used for bearings subjected to high impact loads, such as engine main bearings
G20cr2Ni4	Large bearings with high impact loads, such as those used in rolling mills and mining machinery, are also used to manufacture small and medium-sized bearings that are subjected to high impact loads and high safety requirements.
G10crNi3Mo	Used for large and medium bearings subjected to high impact loads
G20cr2Mn2Mo	Large bearings with high impact loads, such as those used in rolling mills and mining machinery, are also used to manufacture small and medium-sized bearings that can withstand high impact loads and have high safety requirements. This is a new type of steel that is adapted to the characteristics of China's resources.

（四） Special steel

(一) Stainless steel (GB/T 1220-1992)

The characteristics and applications of common stainless steel grades are shown in Table 3-1-25.

Table 3-1-25 Characteristics and applications of commonly used stainless steel grades

type	the name of a shop	Features and Applications
Austenitic Stainless Steel	1cr17Mn6Ni5N	A new grade of stainless steel, replacing grade 1cr17Ni7, exhibits magnetic properties after cold working. Used in railway vehicles.
	1cr18Mn3Ni5N	Nickel steel grade, replacing grade 1 Cr18Ni9
	1cr18Mn10Ni5Mo3N	It has good corrosion resistance to urea and can be used to manufacture urea corrosion equipment
	1cr17Ni7	Cold-worked for high strength, used in railway vehicles and conveyor belt bolts and nuts
	1cr18Ni9	Cold-worked parts exhibit high strength, though their elongation is slightly inferior to that of 1cr17Ni7. These components are used in architectural decoration.
	Y1cr18Ni9	Enhances machinability and ablation resistance, ideal for producing bolts and nuts in automatic lathes
	Y1crl8Ni9se	Enhances machinability and ablation resistance. Ideal for manufacturing rivets and screws on automatic lathes.
	0cr18Ni9	As the most widely used stainless steel, it is used in food equipment, general chemical equipment and nuclear energy industrial equipment
	00cr19Ni10	Steel with lower carbon content than 0cr19Ni9 exhibits superior resistance to intergranular corrosion, making it suitable for welded components without subsequent heat treatment.
	0cr19Ni9N	Adding the letter N to the grade 0cr19Ni9 enhances strength without compromising plasticity, while reducing material thickness. This makes it suitable for structural high-strength components.
	0cr19Ni10NbN	Adding N and Nb to the grade 0cr19Ni9 results in the same properties and applications as 0cr19Ni9.
	00cr18Ni10N	The addition of nitrogen to grade 00cr19Ni10 retains the same properties as the aforementioned grade, with identical applications to 0cr19Ni9N, but exhibits superior resistance to intergranular corrosion.
	1cr18Ni12	Compared with 0cr19Ni9, it exhibits lower work hardenability and is suitable for spinning, special drawing, and cold heading processes.
	0cr23Ni13	Both corrosion resistance and heat resistance are better than ocr19Ni9
	0cr25Ni20	It has better oxidation resistance than 0cr23Ni13 and is actually used as heat resistant steel
	ocr17Ni12Mo2	It exhibits superior corrosion resistance to OCV19Ni9 in seawater and other corrosive environments, making it the preferred material for applications requiring pitting resistance.
	1cr18Ni12Mo2Ti	Equipment resistant to sulfuric acid, phosphoric acid, formic acid and acetic acid, with good resistance to intergranular corrosion

Austenitic Stainless Steel	ocr18Ni12Mo2Ti	Equipment resistant to sulfuric acid, phosphoric acid, formic acid and acetic acid, with good resistance to intergranular corrosion
	oocr17Ni14Mo2	This ultra-low carbon steel, designated as ocr17Ni12Mo2, exhibits superior intergranular corrosion resistance compared to its counterpart ocr17Ni12Mo2.
	ocr17Ni12Mo2N	By adding nitrogen (N) to the alloy OCr17Ni12Mo2, the material's strength is enhanced without compromising ductility, enabling thinner profiles for components with superior corrosion resistance and high strength.
	oocr17Ni13Mo2N	The addition of nitrogen (N) to the grade oocr17Ni14Mo2 retains the same characteristics as the aforementioned grade and shares identical applications with oct17Ni12Mo2N, while offering superior intergranular corrosion resistance.
	ocr18Ni12Mo2cu2	Outperforms OCr17Ni12Mo2 in corrosion resistance and pitting corrosion resistance, making it suitable for sulfuric acid-resistant applications.
	oocr18Ni14Mo2cu2	The ultra-low carbon steel ocr18Ni12Mo2cu2 exhibits superior intergranular corrosion resistance compared to its counterpart ocr18Ni12Mo2cu2.
	ocr19Ni13Mo3	It exhibits superior corrosion resistance to OCr17Ni12Mo2, making it suitable for applications such as dyeing equipment materials.
	oocr19Ni13Mo3	The ultra-low carbon steel ocr19Nil3Mo3 exhibits superior resistance to intergranular corrosion compared to ocr19Ni13Mo3.
	1cr18Ni12Mo3Ti	Equipment resistant to sulfuric acid, phosphoric acid, formic acid and acetic acid, with good resistance to intergranular corrosion
	ocr18Ni12Mo3Ti	Equipment resistant to sulfuric acid, phosphoric acid, formic acid and acetic acid, with good resistance to intergranular corrosion
	ocr18Ni6Mo5	Designed for heat exchangers, acetic acid equipment, phosphoric acid systems, and bleaching units that require chlorine-containing solutions, this material is suitable for environments where oocr17Ni14Mo2 and oocr19Ni13Mo3 are not applicable.
	1cr18Ni9Ti	Used as welding core, anti-magnetic instruments, medical devices, acid-resistant containers, equipment lining, and pipeline transportation equipment and parts
	ocr18Ni1oTi	Add titanium to improve intergranular corrosion resistance. It is not recommended for decorative parts.
	ocr18Ni11Nb	Contains Nb to improve intergranular corrosion resistance
	ocr18Ni9cu3	A steel grade with improved cold workability by adding copper to the composition ocr19Ni9, suitable for cold heading.
	ocr18Ni13si4	Add Ni to the grade OCR19Ni9. Add Si to improve stress corrosion resistance. Suitable for environments with chloride ions.
Austenite | ferrite  Austenite | ferrite	ocr26Ni5Mo2	It has a dual-phase structure, good oxidation resistance and good resistance to pitting corrosion. It has high strength and is used as a corrosion resistant material.
	1cr18Ni11si4AlTi	Manufacture parts and equipment for high temperature concentrated nitric acid medium
	oocr18Ni5Mo3si2	Featuring a duplex structure of ferrite and austenite, it exhibits excellent resistance to stress corrosion cracking and comparable pitting corrosion resistance to OOCR17Ni13Mo2. With high strength, it is suitable for chlorinated environments and widely used in industrial heat exchangers and condensers across sectors including petroleum refining, fertilizer production, paper manufacturing, and petrochemical industries.
type	the name of a shop	Features and Applications
Ferritic	ocr13Al	Materials for steam turbines, quenching components, and composite steels that cool at high temperatures without significant hardening
	oocr12	Compared to OCR13, it has lower carbon content, better bending performance, processing properties, and high-temperature oxidation resistance. It is used in automotive exhaust treatment devices, boiler combustion chambers, and nozzles.
	1cr17	A corrosion-resistant general steel type, used for interior decoration, heavy oil burner parts, household appliances, and household utensils
	Y1cr17	Enhances cutting performance compared to 1cr17. Used in automatic lathes for manufacturing bolts, nuts, and similar components.
	1cr17Mo	An improved version of 1cr17 steel, it exhibits superior resistance to salt solutions compared to standard 1cr17 and is used as an exterior automotive material.
	oocr3oMo2	The high Cr-Mo series features extremely low carbon and nitrogen content, offering excellent corrosion resistance. It is suitable for manufacturing equipment related to organic acids such as acetic and lactic acid, as well as caustic soda equipment. It resists halide ion stress corrosion cracking and pitting corrosion.
	oocr27Mo	It requires performance, application, corrosion resistance, and soft magnetic properties similar to oocr3oMo2
Ma's body type	1cr12	As a good stainless heat resistant steel for steam turbine blades and high stress components
	1cr13	Good corrosion resistance and cutting properties for general purpose cutting tools
	ocr13	Highly durable and impact-resistant components, such as steam turbine blades, structural elements, stainless steel equipment linings, bolts, and nuts.
	Y1cr13	The stainless steel grade with the best machinability for automatic lathes
	1cr13Mo	A high-strength steel with superior corrosion resistance to 1cr13, used for manufacturing steam turbine blades and high-temperature components.
	2cr13	High hardness and good corrosion resistance in quenched state, used for steam turbine blades
	3cr13	Higher hardness than 2cr13 after quenching, suitable for cutting tools, nozzles, valve seats, and valves.
	Y3cr13	Steel to improve 3cr13 cutting performance
	3cr13Mo	High-hardness and high-wear-resistant components such as thermal oil pump shafts, valve discs, valve bearings, medical devices, and springs
	4cr13	High-hardness and high-wear-resistant components such as thermal oil pump shafts, valve discs, valve bearings, medical devices, and springs
	1cr17Ni2	Parts, containers and equipment with high strength and corrosion resistance to nitric acid and organic acids
	7cr17	Hard in hardened state, but more ductile than 8cr17 and 11cr17. Suitable for making cutting tools, measuring tools, and bearings.
	8cr17	Harder than 7cr17 and more ductile than 11cr17, suitable for making cutting tools and valves.
	9cr18	Stainless steel cutting blade tools and shearing tools, surgical blades, high wear-resistant equipment parts, etc.
	11cr17	It has the highest hardness among all stainless steel and heat-resistant steel. It is used for nozzles and bearings.
	Y11 cr17	A steel grade with improved machinability compared to 11cr17, suitable for automatic lathes.
	9cr18Mo	High carbon chromium stainless steel for bearing rings and rolling bodies
	9cr18MoV	Stainless steel cutting blade tools and shearing tools, surgical blades, high-wear-resistant equipment parts, etc.
type	the name of a shop	Features and Applications
Precipitation hardening	0cr17Ni4cu4Nb	Copper precipitation-hardened steel grades for shafts and steam turbine components.
	ocr17Ni7Al	Precipitation-hardened steel grades with aluminum are used for springs, heat rings, and meter components.
	0cr15Ni7M02Al	For high-strength containers, parts, and structural components with certain corrosion resistance requirements

(二) Heat resistant steel  (GB/T 1221-1992)

The characteristics and applications of commonly used heat-resistant steel grades are shown in Table 3-1-26.

Table 3-1-26 Characteristics and applications of commonly used heat-resistant steel grades

the name of a shop	Features and Applications
5cr21Mn9Ni4N	Exhaust valve for gasoline and diesel engines mainly subjected to high temperature
2cr21Ni12N	An exhaust valve for gasoline and diesel engines with antioxidant as the main component
2cr23Ni13	An oxidation-resistant steel designed for repeated heating below 980°C. Suitable for use in heating furnace components and heavy oil burners.
2cr25Ni20	Antioxidant steel for repeated heating below 1035℃, used in furnace components, nozzles, and combustion chambers
1cr16Ni35	Steel with high carburizing and nitriding resistance, reheated below 1035°C. Furnace steel and petroleum cracking equipment.
0cr15Ni25Ti2M0AlvB	Turbine rotor, bolts, blades, and shafts withstanding temperatures up to 700°C
0cr18Ni9	General oxidation-resistant steel, capable of repeated heating below 870℃
0cr23Ni13	Outperforms 0cr18Ni9 in oxidation resistance and can withstand repeated heating cycles below 980% for furnace materials.
0cr25Ni20	Outperforms 0cr23Ni13 in oxidation resistance and can withstand heating up to 1035°C. Suitable for furnace materials and automotive purification systems.
0cr17Ni12M02	High-temperature components with excellent creep strength, such as heat exchanger parts and high-temperature corrosion-resistant bolts
4cr14Ni14W2M0	High thermal strength, used for heavy duty exhaust valve in internal combustion engine
3cr18Mn12si2N	It exhibits high high-temperature strength and oxidation resistance, along with excellent sulfur and carbon deposition resistance. It is used for suspended supports, carburizing furnace components, heating furnace conveyor belts, material trays, and furnace claws.
2cr20Mn9Ni2N	With properties and applications identical to 3cr18Mn12si2N, it can also be used as a salt bath crucible and heating furnace pipe.
0cr19Ni13M03	High temperature has good creep strength, used as heat exchange components
1cr18Ni9Ti	With excellent heat resistance and corrosion resistance, it is used as heating furnace tube, combustion chamber cylinder, annealing furnace cover
0cr18Ni10Ti	Welded structural components for components operating under corrosive conditions at 400 to 900°C
0cr18Ni11Nb	Welded structural components for components operating under corrosive conditions at 400 to 900°C
0cr18Ni13si4	A material with oxidation resistance equivalent to 0cr25Ni20, used in automotive exhaust purification systems
1cr20Ni14si2 1cr25Ni20si2	It has high high-temperature strength and oxidation resistance, but is sensitive to sulfur-containing atmosphere. It has a tendency to fracture in precipitated phase at 600 ~ 800℃, and is suitable for making various furnace components under stress.
2cr25N	High-temperature resistant and highly corrosion-resistant, does not produce flaking oxide scale below 1082℃, used in combustion chamber
0cr13Al	Due to minimal cooling hardening, it is suitable for manufacturing gas turbine blades, annealing chambers, and quenching stands.
00cr12	Resistant to high-temperature oxidation, suitable for welded components, automotive exhaust valve purification devices, boiler combustion chambers, and nozzles.
1cr17	Manufacturing components resistant to oxidation below 900°C, including radiators, furnace components, and oil nozzles
1cr5M0	Resistant to corrosion from petroleum cracking processes. Suitable for use as reheating steam pipes, petroleum cracking pipes, boiler supports, steam turbine cylinder liners, pump components, valves, piston rods, high-pressure hydrogenation equipment parts, and fasteners.
4cr9si2	It has high thermal strength and is used as intake valve for internal combustion engine and exhaust valve for light load engine

4cr10si2Mo	It has high thermal strength and is used as intake valve for internal combustion engine and exhaust valve for light load engine
8cr20si2Ni	Wear-resistant suction and exhaust valves with valve seats
1cr11MoV	It has high thermal strength, good vibration damping and structural stability. It is used in turbine blades and guide vanes.
1cr12Mo	Create turbine blades
2cr12MoVNbN	Manufacturing steam turbine blades, disks, impeller shafts, and bolts
1cr12WMoV	It has high thermal strength, good vibration damping and structural stability. It is used in turbine blades, fasteners, rotors and wheels.
2cr12NiMoWV	High-temperature structural components, steam turbine blades, disc impeller shafts, and bolts
1cr13	For components resistant to oxidation at temperatures below 800°C
1cr13Mo	Manufacturing turbine blades and mechanical components for high-temperature and high-pressure steam
2cr13	High hardness and good corrosion resistance in quenched state. Steam turbine blade
1cr17Ni2	Parts, containers and equipment with high degree of resistance to nitric acid and organic acid corrosion
1cr11Ni2W2MoV	Good toughness and oxidation resistance, good corrosion resistance in fresh water and wet air
0cr17Ni4cu4Nb	Gas turbine compressor blade insulation material for gas turbine engines
0cr17Ni7Al	as high-temperature spring, diaphragm, fastener, bellows

In essence, selecting the ideal steel—be it for structure, tooling, or special applications—is fundamental to your part's success. At Worthy Hardware, our expertise goes beyond just precision machining; we help you navigate material choices. Partner with us to ensure your components are perfectly engineered from the start.