40Cr钢后桥半轴断裂原因分析  

Analysis on Cause for Breaking of Rear Axle Semi-axis of 40Cr Steel

作　　者：朱晓红 ZHUXiaohong(Wuxi Business Testing Technology Co.,Ltd.,Wuxi214104,JiangsuChina)

机构地区：[1]无锡商测检测技术有限公司,江苏无锡214104

出　　处：《热处理》2022年第6期48-50,共3页Heat Treatment

摘　　要：某汽车在行驶了500 km后,其40Cr钢后桥半轴断裂。为查明其断裂的原因,对半轴进行了化学成分分析、断口检验、锻造质量检验、金相检验和硬度测定。结果表明:半轴锻造后未正火处理,中频感应淬火后回火不充分,因此残余应力较大;热处理后机械加工将轴颈处的金属流线切断。以上两个因素导致了半轴早期扭转疲劳断裂。Rear axle semi-axis of a car, made from 40Cr steel, broke after running 500 km. In order to find out thereason why it broke, the chemical composition analysis, fracture testing, forging quality testing, metallographicexamination, and hardness measurements for the broken semi-axis were carried out. The results showed that (a)the semi-axis was not normalized after forging, and was not sufficiently tempered after medium-frequency inductionhardening, therefore had larger residual stress;and (b) the metal flow line at the journal was cut off duringmachining after heat treatment cut off. It is these two factors that resulted in early torsional fatigue fracture of thesemi-axis.

关 键 词：后桥半轴 金属流线 应力集中 扭转疲劳 

分 类 号：TG115[金属学及工艺—物理冶金]