Experimental investigation on CBN turning of hardened AISI 52100 steel

This study investigated the performance and wear behavior of different cubic boron nitride (CBN) tools in finish turning of hardened AISI 52100 steel. Tool performance was evaluated based on the part surface finish and the tool flank wear. Wear conditions of CBN cutting tools were primarily characterized by scanning electron microscopy (SEM). Machining results showed that low CBN content tools (CBN-L) consistently perform better than high CBN content counterparts (CBN-H), despite the CBN-L has inferior mechanical properties. The flank wear rates were proportional to cutting speed and CBN-H showed accelerated thermal wear associated with high cutting temperatures. Reducing depth of cut would only improve surface finish to CBN-L, but not to CBN-H, despite similar wear rates. The transferred layer on the flank wear land may result in adhesion of the binder compound and significantly affect the tool wear process. The metallic binder in CBN-H has stronger affinity to the transferred layer and may result in plucking out of CBN particles and consequent severe abrasive wear.