What is the Best Steel for CNC Machining?

what is the best steel for cnc machining

cnc machining

In CNC machining, steel is considered one of the most used materials due to its cost-effectiveness and specific properties. Several reasons make it a more suitable choice than aluminum and other materials. Steel is an alloy of carbon and iron. Iron is the main element in steel, and it also contains some other elements, including silicon, oxygen, sulfur, and phosphorus. The carbon increases the strength and hardness of the steel.

For the machining process, choose one of the cost savings, having good machinability and higher strength common grade than other alloying elements to produce quality components.

What is CNC Machining Steel?

Steel has high corrosion tensile and temperature resistance, so it is very easy to use it for the CNC machining process. Steel machined parts are used in those sectors which require durable and high-performance parts, such as robotics and aerospace sectors. Because of these physical and chemical characteristics, steel is a smart choice for many applications in the machining process.

It is easily welded and polished and has different physical properties and cost levels than aluminum, so material selection should be performed carefully. Choose materials that are well suited for your project. Check out the material list carefully before ordering a quote for your project.

Top Steel Used for CNC Machining

Steel can use in various sectors such as aerospace, robotics, and automotive sectors due to its physical properties and high performance for many applications. It has different physical properties and cost levels than aluminum, so material selection should be performed carefully, and choose materials that are well suited for your project.

12L14 Steel

12L14 steel is phosphorized and desulfurized carbon steels commonly used in CNC machining to make parts and components. It considers free machining steel due to phosphorus, sulfur, and lead. 12L14 possesses excellent machinability. But, it has lower strength than the other steels because of the lower percentage of carbon steels. It is used in various industries, such as the automotive and aerospace industries, to manufacture different components. It is available in different sizes and shapes.

Mechanical specifications

  • Tensile strength: 231 MPa
  • Elongation at break: 25%
  • Brinell Hardness: 140-170
  • Modulus: 190 GPa


12L14 steel is commonly used for valve components, coupling, fitting, and other industrial purposes. 

1020 Steel

1020 steel is made of carbon and manganese with a low percentage of carbon. It has 0.50% manganese and 0.20% carbon. It has high flexibility and good strength. This steel's range of tensile strength is from 410 to 790 MPa. It can easily weld through welding methods and hardened through cold working methods.

Mechanical specification

  • Tensile strength: 410-790 MPa
  • Elongation: 25%
  • Modulus of elasticity: 210
  • Brinell hardness: 119-235


It can commonly use for simple structural applications. The main applications of 1020 steel are in case hardened situations and cold-headed bolts.

1045 Steel

It is a common steel grade having moderate weldability and other good impact properties. It can be easily welded and respond to heat treatment compared to the other steel compounds. It is highly machinable and also has medium hardenability and medium tensile strength. It may not consider suitable for those applications that may need a material of high strength. 1045 steel does not respond to nitriding because its chemical compositions do not contain appropriate allying elements.

1045 steel is medium carbon steel especially well suited for high-speed applications and mainly used to manufacture gears, shafts, bolts, and studs. It contains carbon, iron, manganese, sulfur, phosphorous, and silicone and can use for its impact resistance and relative strength. It is easier to machine and weld than steels and carbon compounds, whether in normal or cold-drawn conditions. It is suitable for high-strength material and good for applications requiring wear resistance and more strength than mild steel. It is one of the expensive steels and lacks requisite alloying elements, so it can not react favorably to nitriding.

Mechanical specifications

  • Hardness: 88 HRB
  • Elongation at break: 12%
  • Cold-drawn
  • Modulus of elasticity: 206 GPa
  • Ultimate tensile strength: 625 MPa


It is used for industrial applications that need high strength and wears resistance. It can mostly use in spindles, rolls, shafts, etc.

Mild steel A36

Mild steel A36 is widely used in CNC machining. It is a very common steel grade with a low percentage of carbon. So, it is a common grade of low carbon steel, so not suitable for high carbon steels. This steel grade can be easily welded and is very cost-effective compared to other steel grades.

Mechanical specifications

  • Tensile strength: 250 MPa
  • Shear Modulus: 79.3 GPa
  • Elongation at break: 20%
  • Hardness: 119 HBW


It can use to manufacture products that are used for construction purposes. It is mainly used to manufacture the welded metal structures used in industrial construction.

Steel S235JR

Steel S235JR is steel used in CNC machining. It is popular general construction steel and can easily weld without heat treatment. This steel grade is made under the EN 10025-2 standards.

Mechanical specifications

  • Tensile strength: 931 MPa
  • Hardness: 232 HBW
  • Elongation: 44%
  • Yield: 934 MPa


Different steel structures can construct from steel S235JR used to construct automobile bridges, offshore structures, and various industrial facilities.

Steel S355J2

It is micro-alloyed structural steel with good weldability. It has less percentage of carbon, so it is low carbon steel. It also possesses good galvanizing properties because of the controlled content of silicon. It is low-carbon manganese steel with good impact resistance and easy-to-weld properties. It has similar machinability as mild steels.

Mechanical specifications

  • Tensile strength: 585 MPa
  • Elongation: 14%
  • Hardness: 114 HBW
  • Modulus of elasticity: 972 MPa


It is used to manufacture materials for construction purposes. It is used in constructing power transmission towers, gas, oil platforms, and various sectors.

Alloy steel 4140

It has high hardness, resistance, and fatigue strength. It is a hardenable, tough, strong, and ductile grade of steel, but using some elements improves its corrosion resistance and other characteristics such as molybdenum, carbon, and manganese. The molybdenum and chromium make steel 4140 corrosion-resistant. The carbon and manganese contents promote deoxidizations, thus making it hardened. It is challenging and high corrosion-resistant compared to plain carbon steel, mainly used for the manufacturing processes of valve components, gears, pins, and shafts components. It is inexpensive, strong, durable, and has zero cold drawn.

It is more challenging than plain carbon steel and needs more force for good and effective forming. Annealing is essential when machining 4041 steel with low carbon steels. It can demand high material costs than pure carbon steel and have high machining costs. It can be one of the durable, strong, and cost-effective materials.

Mechanical specifications

  • Elongation at break: 18%
  • Hardness: 35 HRC
  • Cold drawn: zero
  • Modulus of elasticity: 205 GPa
  • Ultimate tensile strength: 1140 MPa


This alloy of 4140 is a readily machinable and highly versatile grade. It is a commonly used metal for general-purpose steel parts to make valve components, pins, gears, and shafts.

Alloy steel 4340

Steel 4340 is a low alloy metal with high strength and toughness, which can even maintain at high temperatures. It is one example of the type of steels that exhibits an excellent quality of toughness and retains its properties at relatively high temperatures while used in a machine. It can be challenging to heat treatment and used in machines by applying all conventional methods and techniques.

Mechanical specifications

  • Tensile strength yield:470 MPa
  • Elongation at break: 22%
  • Shear Modulus: 74 GPa
  • Hardness:217 HRC


The common applications of steel 4340 include shafts, gears, and structural parts.

Alloy steel 1.7131 (16MnCr5)

It is formulated for the primary forming of wrought products. 1.7131 is the EN numeric designation, while the 16MnCr5 is the EN chemical designation. 1.7131 has low embodied energy. You can hot work alloy steel 1.7131 at 205 to 58°C, and it can use for a variety of applications such as pumps, fitting, gears, and combustion engines.

Mechanical specifications

  • Tensile strength: 327 MPa
  • Hardness: 214 HBW
  • Elongation at break: 44%


It is mainly used in pumps and fittings, internal combustion engines, tools, gears, valve bodies, etc.

Tool steel D2

It is an air-hardening tool steel with high chromium and carbon contents. It can be heat treated to compressive strength and high hardness. Tool D2 shows high wear resistance. It has good abrasion and corrosion resistance and wears properties. It is heat treatable Due to its high chromium tool steel, it has mild corrosion resistance material properties and increased hardness in 55-62 HRC. It is used to produce punches, knives, tools, Scarpe chopper components, and metals.

Mechanical specifications

  • 0.2% compressive yield strength: 1690 MPa
  • Relative density: 97%
  • Elastic modulus:187 GPA
  • Hardness: 55HRC


It is used in cold work applications that need abrasion and high corrosion resistance, sharp edges, and compressive strength.


Steel is a common material used for various purposes due to its exclusive properties. The different alloy of steel is widely used in CNC machining. These other alloys of steel have different physical as well as mechanical properties. They also vary in chemical composition. All steel alloys contribute to equally manufacturing various industrial and other materials. These alloys play an important role in manufacturing different products and are available at variable costs. These steel alloys are considered best for CNC machining.

Worthy hardware is one of the top & most experienced precision machine shops in China with CNC machinng steel material parts. Call us now or contact with us via email for your CNC milling and CNC machining specifications and tolerances.


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