精密GCr15轴承的热处理工艺改进

Improvement of heat treatment process for precise GCr15 bearings

毛坯棒料出现淬火裂纹主要是由于原材料毛坯棒料尺寸过大,组织存在网状二次渗碳体,淬火时预冷不充分,组织应力及热应力的共同作用;生产出的轴承尺寸稳定性差的主要原因是由于在进行淬火及低温回火后并未消除残余奥氏体造成的影响.改进整个热处理工艺路线后精密GCr15轴承尺寸稳定性提高,寿命延长,达到预期效果.

The occurrence of quench crack in the GCr15 blank rods was attributed to the over-size of the rods, the existence of network secondary cementite in the microstructure, inadequate pre-cooling before quenching, and the combined effect of microstructural and thermal stresses on the steel. And, the poor size stability of the finished bearings was caused by the remained austenite that was not completely eliminated by the subsequent low temperature tempering. The size stability and service time of the precise GCr15 bearings were found to be markedly increased by adopting an improved heat treatment process.