35CrMo钢制球销断裂失效分析及对策  

Analysis and countermeasures on failed ball pin of 35CrMo steel

作　　者：林仁敢 张小可 纪仁峰 LIN Rengan;ZHANG Xiaoke;JI Renfeng(Baosteel Special Metals Long Product Co.,Ltd.,Shanghai 200940,China)

机构地区：[1]宝钢特钢长材有限公司,上海200940

出　　处：《宝钢技术》2023年第5期6-10,17,共6页Baosteel Technology

摘　　要：转向球销是保证汽车转向系统正常运转的关键零部件,某用户在进行台架测试时,球销零件中部发生横向断裂失效,失效球销体材料为35CrMo。通过成分检测、金相组织观察、断口扫描等测试手段,全面分析球销的失效原因,同时针对存在的异常问题进行了优化改善。结果显示:球销零件外表面存在车削痕和凹坑等缺陷,是导致球销在服役过程失效的主要原因。此外,零件淬火过程中铁素体未完全转变为奥氏体,导致回火组织残留较多条状铁素体,影响调质后的整体性能,进一步加剧了零件的疲劳断裂。通过优化热处理工艺和改善零件表面质量后,测试过程未再出现类似失效情况。The ball pin is a type of key component to ensure the normal operation of an automobile steering system.A ball pin made of 35CrMo steel has cracked and failed during bench testing.The failure causes of cracked ball pins were studied by means of chemical composition analysis,metallographic examination and SEM analysis.At the same time,the improvement strategy for the failure reasons was improved and verified.The results show that pit defects exist on the ball pin surface,which are the main reasons leading to the failure of the ball pin in service.In addition,because the ferrite was not completely transformed into austenite during the quenching process of the parts,more strip ferrite structure remained in the tempered structure.It affected the overall performance after tempering and further aggravated the fatigue fracture of the parts.No similar failure occurred again in the follow-up test process after the heat treatment process optimizing and the surface quality of the parts improving.

关 键 词：球销 断裂失效 调质 金相组织 

分 类 号：TG115[金属学及工艺—物理冶金]