Study on Machining of Stainless Steel (2nd report) : Selection of Suitable Tool Material and Tool Geometry for Face Milling

The suitable tool materials for lathe turning were M20 and P20 containing a considerable amount of TiC and TaC in 1st report. As milling process is a discontinuous cutting, the impact forces act upon the cutting edges when they engage and disengage the workpiece. And the tools are also heated and cooled alternately by cutting and idle processes per one cycle. Therefore, the suitable tool material for face milling differs from one for lathe turning. The suitable tool material for face milling 18-8 stainless steel is selected among the same tools in 1st report. The suitable nose radius and width of land of cutting edges are also selected in this experiment. 1. Suitable tool material differs for cutting speed range, that is, high speed steel tool SKH4 and sintered carbide tool M20 suit to face milling operation in low cutting speed and other cutting speed range respectively. 2. Remarkable separation of welds appears on face milling 18-8 stainless steel. If it appears near cutting edge, the cutting edge should fail at once. Because of suitable nose radius and width of land decreasing the appearance and separation of welds, tool life increases and useful cutting speed range expands.