Hard turning of GCr15 steel with chamfered PCBN tools

This work investigates the cutting performance of chamfered PCBN tools in hard turning of GCr15 bearing steel. Experimental study was performed on a NC lathe. Cutting forces were measured by using a dynamometer. Cutting temperature was measured by using an infrared thermal imager. The variation of cutting forces and cutting temperature with the chamfer angles are investigated and discussed. The surface roughness of the workpiece and flank wear of the tool during the machining is concerned, and the relationship between the surface roughness and flank wear is studied. The tool rejection criteria for the hard turning of GCr15 steel is proposed considering surface roughness and flank wear. The wear patterns of the tool were investigated using scanning electron microscope (SEM), and the wear mechanism is discussed. It is found that crater and adhesion are the dominant wear mechanism of the rake face, and abrasive wear is the dominant wear mechanism of the flank of the PCBN tool in hard turning of GCr15 steel.