Generally, the machinability of stainless steel is worse than that of other steels, which means that the machinability of austenitic stainless steel is poor. It is caused by the severe work hardening and low thermal conductivity of austenitic stainless steel. Therefore, the stainless steel needs to use water-based cutting coolant during the cutting process to reduce the thermal deformation of the cutting. Especially when the heat treatment in the welding process is not good, no matter how to improve the cutting accuracy, its deformation is inevitable.
The cutting performance of stainless steel such as martensitic stainless steel and ferritic stainless steel is not much different from that of carbon steel if it is not cut after quenching. However, the higher the carbon content of both steel bodies, the worse the cutting performance.
Precipitation hardening stainless steels show different cutting properties due to their different structures and processing methods, but usually their cutting properties are the same as martensitic stainless steels of the same series and strength in the annealed state.
In order to improve the cutting performance of stainless steel, it can be achieved by adding elements such as sulfur, lead, bismuth, selenium, and tellurium. For example, adding elements such as sulfur, selenium, and tellurium can reduce tool wear, and adding elements such as lead and bismuth can improve the cutting state. Although the addition of sulfur can improve the cutting performance of stainless steel, the corrosion resistance of stainless steel will be significantly reduced because it exists in the structure of the steel in the form of MnS compounds. In order to solve this problem, a small amount of molybdenum or copper is usually added to improve the corrosion resistance of stainless steel to corrosive media such as acetic acid.
