汽车发动机前制动软管螺栓断裂原因  

Reasons for bolt fracture of front brake hose of automobile engine

作　　者：李朝辉 盖跃华 LI Zhaohui;GAI Yuehua(Quality and Technical Supervision and Evaluation Office,Shenzhen Public Standard Intellectual Property Appraisal and Evaluation Center,Shenzhen 518000,China)

机构地区：[1]深圳市公标知识产权鉴定评估中心质量技术监督评价事务所,深圳518000

出　　处：《理化检验（物理分册）》2023年第12期59-62,共4页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：某汽车发动机前制动软管螺栓发生断裂现象,采用宏观观察、化学成分分析、扫描电镜分析、金相检验、硬度测试等方法分析了螺栓断裂的原因。结果表明:未对螺栓进行热处理,导致冷作硬化没有消除;在酸洗电镀工序中,氢离子浸入螺栓的根部,使螺栓根部发生氢致延迟断裂。The bolt of front brake hose of an automobile engine was broken.The causes of bolt fracture were analyzed by means of macroscopic observation,chemical composition analysis,scanning electron microscope analysis,metallographic examination and hardness test.The results show that the bolt was not heat treated,resulting in cold hardening was not eliminated.In the pickling and electroplating process,hydrogen ions were immersed in the root of the bolt,causing hydrogen induced delayed fracture at the root of the bolt.

关 键 词：螺栓 冷作硬化 氢致延迟断裂 热处理 

分 类 号：TB31[一般工业技术—材料科学与工程] TG115.2[金属学及工艺—物理冶金]