35CrMo钢圆柱销纵向开裂原因分析

Causean analysis on longitudinal cracking of 35CrMo steel cylinder pin

某标准件厂生产的35CrMo钢圆柱销在入厂复验进行拉伸试样加工时发现内部存在纵向开裂,通过对该圆柱销进行化学成分、显微组织、裂纹及断口形貌等检验分析,查明了开裂的原因。结果表明,35CrMo钢圆柱销开裂是淬火过程中产生的纵裂,热处理过程中有轻度的过热,以及纵向存在粗大的夹杂物等脆性相是开裂的根源。通过适当调整热处理工艺、选择纯净的原材料可避免此类问题的发生。

Longitudinal cracks were found in the 35CrMo steel cylinder pin produced by a standard parts factory during tensile sample manufacturing for re-examination.The causes of the cracking were found out by analyzing the chemical composition,microstructure,crack and fracture morphology of the cylinder pin.The results show that the cracking of the 35CrMo steel cylinder pin is the longitudinal crack occurred during quenching.The cracking is caused by slightly overheating and coarse inclusions in longitudinal direction.This kind of problem can be avoided by adjusting heat treatment process and selecting pure raw materials.