Chip Flow and Notch Wear Mechanisms during the Machining of High Austenitic Stainless Steels

Notch wear at the depth of cut line is a serious problem during the machining of high-austenitic stainless steels. The mechanism of such notch wear was investigated through special step-turning tests involving four high austenitic stainless steels with cemented carbide tool. Chip studies and micro-hardness measurement of work material at the chip flow region, along with SEM studies were carreid out to elucidate the role of work hardening and chip flow upon wear. These clearly showed severe localised shear and chip side flow and its strong adhesive interaction with the tool material in the notch region. The critical initiation of the notch seems to be related to factors such as, transverse stress and temperature distribution and chemical interaction. Subsequent progress of notch was often through the interaction of the localised shear region of the chip and the exposed binder phase of the tool. Direct evidence between the strain hardening index of the work materials and the level of notch wear was also observed.