Wear characteristics of various cutting tools in steel machining

Abstract

The present paper describes tool wear characteristics of various cutting tools in steel machining. Tool wear tests are extensively conducted in which plain carbon steels, high manganese steel and austenitic stainless steel are turned using various tungsten carbides and alumina tools. Not only wear rates but also distributions of temperature and stresses on the tool face are measured, for which the embedded thermocouple method and split-tool dynamometry are employed. Tool wear characteristics are discussed on the basis of the experimental data thus obtained. A wear model based on thermally-activated adhesion is found to be applicable to the description of crater wear which mainly depends on tool temperature and contact normal stress; however, a simulation experiment reveals that in steel machining a temperature-dependent abrasion model predominates over the adhesion model for the representation of flank wear in which temperature drops below 1,175 K for a P20 tool. Consequently the mechanism of crater and flank wear consists of both adhesion and abrasion, and a combined wear characteristic equation is proposed. Finally, an analytical prediction method combining the energy method with the estimation of the wear characteristic constants is proposed, its suitability being demonstrated when an 18%Mn-5%Cr alloy steel is turned using a P20 single point tool.