Measurement of Cutting Temperature and Properties of Chips on the Machining of Bearing Steel in Supercooled Austenite

A new machining process, called auscutting, has been developed, in which the cutting operation is made in supercooled austenite state during quench cooling. To control the cutting conditions and lengthen the tool life, the cutting temperature is measured in this process by a tool-work thermocouple method. The black ceramic tool (Al2O3+TiC) used has some electric conductivity and the black ceramic-bearing steel thermocouple exhibits the thermo-e.m.f. of about 1 mV/100°C. The influence of cutting conditions on the cutting temperature and the microstructure of chips is investigated.The results obtained are summarized as follows:(1) The cutting temperature in auscutting is about 200°C higher than that in usual cutting process for the annealed steel and reaches 1100°C at the cutting speed of 200 m/min and the feed of 0.2 mm/rev.(2) The chip disposability is very good, because the chips are saw-toothed and hardened after cooling to room temperature.