COMPUTER-AIDED SIMULATION AND EXPERIMENTAL STUDIES OF CHIP FLOW AND TOOL WEAR IN THE TURNING OF LOW-ALLOY STEELS BY CEMENTED CARBIDE TOOLS

A finite element modelling (FEM) analysis of chip flow has been developed on a CAD (computer-aided design) computer and used to aid studies of the wear of cemented carbide tools turning an aluminium-deoxidized and an aluminium-deoxidized, calcium-treated resulphurized low alloy steel. The latter steel formed a Ca-Mn-S deposit on the tool rake face and, at a given feed and speed, machined with 20% lower tool forces and 60-fold less crater wear than the former. Subsidiary tests showed both steels to have the same mechanical properties but that the Ca-Mn-S deposit reduced chip-tool friction; input of these data to the FEM analysis resulted in lower predicted cutting forces and temperatures for the deposit-forming steel. The temperature calculations, with a thermal activation wear model, indicate provisionally that the crater-wear-reducing properties of the deposit were multiplicatively 20-fold due to its effect as a diffusion barrier and three-fold due to lower temperatures. © 1990.