How much do you know about CNC stainless steel machining?

cnc machining

CNC Stainless steel machining parts have been around for many years, and they're still going strong. CNC parts are used in heavy industry as well as light manufacturing because of the good formability that allows them to be worked on without affecting other aspects like durability or strength outlasting metal alloys by leaps and bounds!

At present, the application prospect of stainless steel has become more and more promising! As a CNC machining parts vendor, Worthy Hardware can perfectly process a piece of stainless steel material into parts required by various industries. We are a professional CNC machining manufacturer. According to our 25 years in the CNC machining manufacturing field, from this blog, you will know more about stainless steel alloys machining knowledge.

1. What is stainless steel material?

Stainless Steel is the abbreviation of stainless acid-resistant steel, resistant to air, steam, water, and other weak corrosive media or stainless steel is called stainless steel

2. Classification of stainless steel ?

Stainless steels are commonly grouped into martensitic stainless steels, ferritic stainless steels, austenitic stainless steels, and precipitation-hardening stainless steels

(1) Martensitic stainless steels

High strength, but poor plasticity and weldability. Because of the higher carbon content, it has higher strength, hardness, and wear resistance, but the corrosion resistance is slightly worse. It is used for higher mechanical properties and corrosion resistance. Some general parts are required, such as springs, steam turbine blades, hydraulic valves, etc. This type of steel is used after quenching and tempering. Annealing is required after forging and stamping.

(2) Ferritic stainless steels

Containing 15% to 30% chromium. Its corrosion resistance, toughness, and weldability increase with the increase of chromium content. The chloride stress corrosion resistance is better than other types of stainless steel. Ferritic stainless steel has high chromium content, and its corrosion resistance and oxidation resistance are compared. Good, but the mechanical properties and process performance are poor. It is mostly used for acid-resistant structures with little stress and as anti-oxidation steel. This type of steel can resist corrosion from the atmosphere, nitric acid, and salt solutions, and has the characteristics of good high-temperature oxidation resistance and low thermal expansion coefficient. It is used in nitric acid and food factory equipment, and can also be used to make parts that work at high temperatures, such as gas turbine parts, etc.

(3) Precipitation hardened stainless steels

The alloy composition content of precipitation hardening stainless steel grades is higher than that of ordinary martensitic stainless steel grades.They contain nickel and are hardened by adding copper, aluminum, titanium, niobium, and molybdenum elements for aging treatment.

(4) Austenitic stainless steel

Good performance, resistant to corrosion by various media. Because it contains a large amount of Ni and Cr, this kind of steel has good plasticity, toughness, weldability, corrosion resistance, and non-magnetic or weak magnetic properties. It has good corrosion resistance in oxidizing and reducing media. It is used to make acid-resistant Equipment, such as corrosion-resistant containers and equipment linings, pipelines, nitric acid-resistant equipment parts,etc.

3. Which stainless steel is difficult for CNC machining?.

Compared with most martensitic or ferritic stainless steels, the cutting of austenitic stainless steels is much more difficult. The main difference is that the austenitic stainless steels in a small annealed state are very sticky, and the cutting process tends to be difficult. The generation of fibrous cutting chips can only be avoided by using a special process. In addition, the high work hardening rate during processing will also cause cutting difficulties.

(1) Stainless Steel 303

SS303 is an austenitic type of free-cutting stainless and wear-resistant acid steel containing sulfur and selenium respectively. It is used in occasions that require free cutting and a high surface finish.

(2)Stainless Steel 304

SS304 is a common material in stainless steel, with a density of 7.93 g/cm³, which is also called 18-8 stainless steel in the industry. High operating temperatures resistance of 800℃, good processing performance, high toughness, widely used in industry and furniture decoration industry and food and medical industry.

(3)Stainless Steel 316

Due to the addition of the Mo element, 316 stainless steel has greatly improved its high corrosion resistance and high-temperature strength. The high-temperature resistance can reach 1200-1300 degrees, and it can be used under harsh conditions.

These three above types are the most popular materials for austenitic stainless steel, SS303 is free cutting, 304 and 316 are very tough to the machine.

4. Difficulties of stainless steel precision machining.

Many CNC machine shop manufacturers will be confused when facing the precision machining of stainless steel. Different grades of stainless steel materials have different hardness and slightly different characteristics. In the field of CNC machining, are there any difficulties in stainless steel machining? Worthy Hardware is very strong in making all kinds of precision CNC machining parts. We have made an inventory of the difficulties in stainless steel processing. Let’s take a look at what are there?

(1) Cutting force is large

Stainless steel has a large plastic deformation during the cutting process, resulting in an increase in cutting force. Stainless steel has serious work hardening and high thermal strength, which further increases the cutting resistance, and it is more difficult to curl and break the chips.

(2) Severe work hardening

The plasticity of stainless steel is large, the character is distorted during plastic deformation, and the strengthening coefficient is very large; and the austenite is not stable enough. Under the action of cutting stress, part of the austenite will be transformed into martensite; in addition, the compound impurities are in the cutting heat Under the action of, it is easy to decompose into a diffuse distribution so that a hardened layer is produced during cutting.

(3) Chips are not easy to break, easy to stick

The plasticity and toughness of stainless steel are very large. The chips are continuous during the machining stainless steel process, which not only affects the smooth operation of the operation but also crushes the machined surface. Under high temperature and high pressure, stainless steel has a strong affinity with other metals, and it is easy to produce adhesion phenomena and form built-up tumors, which not only aggravates tool wear but also tears and deteriorates the processed surface.

(4) High cutting temperature

During cutting, the plastic deformation and friction with the tool are very large, and a lot of cutting heat is generated; a large amount of cutting heat is concentrated on the interface between the cutting area and the tool-chip contact, and the heat dissipation condition is poor.

(5) Large linear expansion coefficient

The coefficient of linear expansion of stainless steel is about 1.5 times that of carbon steel. Under the action of cutting temperature, the workpiece is prone to thermal deformation, and the dimensional accuracy is difficult to control.

(6)The tool is easy to wear

The affinity in the process of cutting stainless steel causes bonding and diffusion between the tool and the chip, thereby causing bonding wear and diffusion wear of the tool; in addition, the hardness of the carbide (such as TiC) particles in the stainless steel is very high, and it is directly cut during cutting. Contact with the tool, friction, abrasion of the tool, and work hardening will all increase the wear of the tool.

Through the above article, we know more about stainless steel materials, and the basic performance of the cutting processing difficulties of stainless steel precision parts is the cutting force, work hardening, high viscosity, high temperature, high linear expansion coefficient, and easy to wear tools.

Dongguan Worthy Hardware, founded in 1998 by Mr. Su, has been very professional at processing various stainless steel parts. Due to its high hardness, CNC machining manufacturers are not willing to make them. However Worthy Hardware together with its technical team continuously optimizes our technology for optimal results. At present, our products are widely used in medical, communications, optoelectronics, kitchenware, aviation, automobiles, and other fields

We take pride in every project because it demonstrates that we care about quality and detail. Contact us for a try! We will not let you down.


Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.