Study on Machining of Stainless Steel (1st report) : Selection of Suitable Tool Material for Turning

Many stainless steels are used for the thermal resisting materials and the parts of chemical equipment. The poor machinability of 18-8 stainless steel is due to the occurrence of the remarkable welds and work hardening property in machining. The suitable tool material for lathe turning 18-8 stainless steel is selected by the observation of tool failures among the sintered carbides (JIS. K20,M20,P20), high speed steel (SKH4) and oxide ceramic tool. 1. The suitable tool materials are M20 and P20 which contain a considerable amount of TiC and TaC. 2. Remarkable boundary flank wear (V_B”) appears in the machining of this workpiece. The amount of V_B” in case of positive rake face is less than in that of negative rake face. 3. Generation of V_B” may show that the deformation of chips at the boundary of the main cutting edge is severer than at any other place in cutting edge.