Effect of porosity on the machinability of P/M 304L stainless steel

An experimental investigation of the effect of the porosity of P/M 304L austenitic stainless steel on its machinability is described. The machinability of the work materials was evaluated using twist drills with drill wear, drill life, and drill thrust and torque as the measured responses. The study demonstrated that the surface layer of the machined surface was work hardened and densified and that the magnitude of these effects increased with porosity and the proximity to the axis of the hole. The thrust and torque increased with decreasing density down to 70 percent of theoretical density, then decreased as the density was further decreased. An interrupted cutting model previously suggested to explain the machinability of P/M stainless steels was not supported by the data obtained in this study.