Hard turning of AISI 52100 using PCBN wiper geometry inserts and the resulting surface integrity

To allow for high productivity, high flexibility and avoidance of coolants, hard turning is nowadays an alternative to grinding in the finishing of workpieces in hardened steels. Using wiper PCBN inserts reduces surface roughness compared to machining experiments with conventional inserts at increased feed rate. Although these advantages are known, the effect of wiper PCBN inserts on surface integrity in a hard turning process is not well described in literature. This paper aims at investigating the effect of wiper PCBN inserts on surface integrity and cutting forces in finishing by hard turning of through hardened AISI 52100 (100Cr6) (58-62 HRC). A model based on statistical design of experiments was established to predict cutting forces and surface roughness within a range of cutting parameters. The assessment of surface and subsurface integrity reveals that, when compared to conventional geometry inserts, the application of PCBN wiper inserts leads to significantly improved surface roughness and higher compressive residual stresses.