The wear mechanisms of the tool made of
cubic boron nitride (CBN) in cutting
austenitic manganese steel at semi-precision
processing conditions (cutting thickness a_p=0.5 mm, feeding rate f=0.3 mm/r, dry cutting) were investigated. The cutting temperature was measured with a photoelectric thermometer (WDH-II), the effect of cutting duration and cutting speed on the wear behavior of the tool was explored. The wear breadth of the tool was determined on a tool-microscope, and the rear face and rake face morphologies and elemental compositions of the tool were observed with a scanning electron microscope and determined on an energy dispersive spectrometer, respectively. It was found that the CBN tool experienced severe mechanical wear in cutting the
austenitic manganese steel within 400~700 ℃, which was attributed to the abrasion of the γ phase and the (Fe,Mn)_3C precipitated therefrom. The tool was dominated by diffusion wear at a cutting temperature above 800 ℃ at which single γ phase and the tool surface material underwent inter-diffusion. Moreover, the CBN tool was much superior to those tools made of SiC or Si_3N_4 in terms of the performance at an excessively high-speed cutting.