Mirror Finishing of Austenitic Stainless Steel with a Cermet Insert

摘要

Stainless steel SUS304 is one of the typical difficult-to-cut materials due to strong tendency to adhesion and work hardening. Therefore finished surface becomes rough in machining operations. In this report, precision cutting of SUS 304 is discussed. Surface roughness depends on accuracy of the machine tool, adhesion and roughness of tool flank. We analyzed the factors of surface roughness in turning of SUS304 on an engine lathe. M20 tungsten carbide inserts, coated carbide inserts and cermet inserts were used. Peak-to-valley height of machined surface included approximately 1μm of machine error. Surface profile reflected roughness of tool flank. Polished flank decreased the roughness of finished surface. Adhesion was least in the case of cutting with cermet inserts. We also conducted face turning of SUS304 on an ultra-precision lathe with cermet inserts. Flank of the inserts were polished to 100nmRz. We obtained 50nm of minimum peak-to-valley height and 220nmRz of surface roughness.