1965 Volume 51 Issue 7 Pages 1260-1267
As the requirements for the ball bearing steel in Japan are quite severe, its manufacturing is one of the most expensive, though its components are cheap.In this thesis, the shortening of spheroidizing process and its effect in actual service are reported. The shortening of spheroidizing time is realized by austempering annealing. Spheroidizing can be finished in less than 30min by this new process. The properties of the steel made by this new process were investigated by static flattening test and life test. The former test shows the'static strength of material and the latter its dynamic properties. The life test was conducted using the accelerated life test equipment invented by the Government Mechanical Laboratories in Japan. The results show no difference between the steels made by the conventional process and by this new short process except a little increase of hardness. But this higher hardness can be neglected in cutting by lathe. Consequently the new process will be. able to contribute to cost reduction.