Abstract
A new machining process, called auscutting, has been developed in which the cutting operation is per-formed in supercooled austenitic state during quenching. In this paper, the optimum heat cycle condition which saves much thermal energy and time in the continuous process for manufacturing bearing races from hot forging to auscutting is investigated from the viewpoint of the quenched structure. Furthermore, under the obtained optimum heat cycle condition, the machinability and the rolling fatigue life are investigated.
The results obtained are summarized as follows:
(1) The optimum heat cycle process with auscutting is (hot forging)→(air cooling to 650°C)→(slow heating to 850°C and soaking)→(quenching to 200°C)→(auscutting)→(air cooling). Thermal energy in this process with auscutting is about 36% less than that in the conventional process.
(2) Under the optimum heat cycle, the machinability in auscutting is not worse than that under theconventional heat cycle and the rolling fatigue life is about 3-4 times longer than that under the conven-tional heat cycle.
