Heat treatment process for bushing used in track of endless track tractor.

摘要

This heat treatment process is applicable to bushings used in tracks of endless track tractor and does not deteriorate wear resistance, fatigue strength, and toughness of bushings. As this method can reduce the number of heat treatment process steps and save energy, it enhance productivity and reduces cost of bushing manufacture. These advantages are achieved by the treatment steps of heating a bushing made of middle carbon low alloy steel material from the outer peripheral surface thereof until the inner circumferential surface thereof achieves the temperature range of Ac3