Because the precision parts of stainless steel has excellent corrosion resistance, formability, compatibility, and in a wide temperature range series features such as strong toughness, so in heavy industry, light industry, supplies industry and building decoration and other industries have extensive application.
People place the chromium content is more than 12% or nickel content more than 8% of alloy steel is stainless steel. This kind of steel in the atmosphere or in a corrosive medium has certain corrosion resistant die casting parts ability, and under the high temperature (> 450 ℃) with high strength. Chromium content of 16% ~ 18% of steel called acid steel or acid stainless steel, traditionally known as stainless steel.
Due to the characteristics of stainless steel is, more and more widely used in aviation, aerospace, chemical, petroleum, construction and food industries and daily life.
Stainless steel in the process of CNC cutting has the following several aspects:
Work hardening seriously: stainless steel and plastic, plastic deformation character contorted, strengthening coefficient is very big, And austenite is not stable, under the action of cutting stress, experience of austenite into martensite; Combined with compound impurities under the action of heat cutting, easy to decompose a diffuse distribution, make produce when machining hardened layer. A feed or before the procedure, the work hardening phenomenon seriously affect the follow-up process smoothly.
Cutting force big: stainless steel plastic deformation in the process of cutting, cutting force increases. The work hardening of stainless steel, high hot strength, further increasing the cutting resistance, chip curling broken is more difficult.
High cutting temperature, cutting the plastic deformation and friction between the tool and are very big, the cutting heat; A large number of cutting heat is concentrated in the cutting area and the knife - crumbs in contact interface, poor heat dissipation condition.
Chip is not easy to break and easy to bond: the plasticity and Investment casting parts toughness of stainless steel are big, CNC processing chip continuously, not only affect the operating smoothly, chip will hurt has been processed surface. Under high temperature and high pressure, stainless steel and other metal affinity is strong, easy to produce adhesion phenomenon, and form the devolop tumor, exacerbating the cutting tool wear and tear phenomenon will appear again and make the machined surface has been deteriorating.
Affinity function in the process of cutting tool wears: cutting stainless steel, the knife - the generation between chip bonding, diffusion, which produce adhesion wear, diffusion wear of cutting tool and the tool rake face of produce crater, cutting edge can also form tiny flake and gap; With stainless steel of carbide particles (TiC) hardness is high, direct contact with the tool when cutting, friction, abrasion cutting tools, and work hardening phenomenon, all can make the tool wear.
The linear expansion coefficient of linear expansion coefficient of large: stainless steel which is about 1.5 times that of carbon steel in the function of cutting temperature, easy to produce hot deformation of workpiece, dimension precision are harder to control.
Stainless steel parts because of its special performance and more and more die casting parts used in electric power, aviation, aerospace, oil and food industry etc. Although stainless steel cutting with high thermal strength, large plastic deformation, strain hardening seriously, cutting heat and heat dissipation difficulties, but by selecting the suitable cutting tool, cutting fluid, cutting dosage, processing methods, finally can guarantee the quality of stainless steel.