Due to its excellent corrosion resistance, formability, compatibility and toughness in a wide temperature range, stainless steel precision parts have been widely used in heavy industry, light industry, daily necessities industry and building decoration industry.

The alloy steel containing more than 12% chromium or more than 8% nickel is called stainless steel. This kind of steel has certain corrosion resistance in atmosphere or corrosive medium, and has higher strength at higher temperature (> 450 ℃). The steel with chromium content of 16% - 18% is called acid resistant steel or acid resistant stainless steel, which is commonly called stainless steel.

Because of the above characteristics, stainless steel is more and more widely used in aviation, aerospace, chemical industry, petroleum, construction and food industry and daily life.

Stainless steel has the following characteristics in CNC cutting process

Severe work hardening: the plasticity of stainless steel is large, the character of plastic deformation is crooked, and the strengthening coefficient is large; and the austenite is not stable enough, under the action of cutting stress, part of austenite will be transformed into martensite; in addition, compound impurities are easy to decompose and disperse under the action of cutting heat, so that the hardened layer will be produced during cutting. The work hardening phenomenon caused by the previous feed or the previous process seriously affects the smooth progress of the subsequent process.

Large cutting force: the plastic deformation of stainless steel in the cutting process is large, which leads to the increase of cutting force. The severe work hardening and high thermal strength of stainless steel further increase the cutting resistance, and it is difficult to curl and break the chip.

High cutting temperature: when cutting, the plastic deformation and friction with the tool are very large, resulting in more cutting heat; a lot of cutting heat is concentrated in the cutting area and the tool chip contact interface, resulting in poor heat dissipation conditions.

Chip is not easy to break, easy to bond: stainless steel plasticity, toughness are great, CNC machining chip continuous, not only affect the smooth operation, chip will crush the machined surface. Under high temperature and high pressure, the affinity between stainless steel and other metals is strong, so it is easy to produce adhesion phenomenon and form chip accumulation tumor, which not only aggravates tool wear, but also causes tearing phenomenon and worsens the machined surface.

Tool wear: the affinity effect in the process of cutting stainless steel makes the bond and diffusion between the tool and the chip, resulting in the bond wear and diffusion wear of the tool, resulting in the crescent depression on the front face of the tool, and the tiny spalling and notch on the cutting edge. In addition, the hardness of carbide particles (such as TIC) in stainless steel is very high, so it directly contacts and rubs the tool when cutting Tool wear will be aggravated by tool wear and work hardening.

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

Stainless steel parts are more and more used in electric power, aviation, aerospace, petroleum and food industry because of their special properties. Although stainless steel cutting has the characteristics of high thermal strength, large plastic deformation, severe work hardening, more cutting heat and difficult heat dissipation, the processing quality of stainless steel can be guaranteed by selecting appropriate cutting tools, cutting fluid, cutting parameters and processing methods.