50CrVA扭力杆早期疲劳断裂分析  

Early Fatigue Fracture Analysis of 50CrVA Torsion Bar

作　　者：袁桥军 陈礼洲 YUAN Qiaojun;CHEN Lizhou(Xiangtan Iron and Steel Group Co.,Ltd,Xiangtan 411101,China;Wuhan Branch of China Classification Society,Wuhan430030,China)

机构地区：[1]湘潭钢铁集团有限公司,湖南湘潭411101 [2]中国船级社武汉分社,湖北武汉430030

出　　处：《金属材料与冶金工程》2023年第1期25-28,43,共5页Metal Materials and Metallurgy Engineering

摘　　要：通过对50CrVA扭力杆化学成分分析、宏观和微观断口观察、金相组织检查、硬度检验,分析了扭力杆早期疲劳断裂的原因。结果表明:扭力杆表面进行了补焊修复处理,而补焊区域存在未融合和裂纹等缺陷,这些缺陷在断裂中起到疲劳源的作用,是扭力杆早期断裂的最主要原因;原材料中Mn、Cr、V等元素偏低,降低了淬透性,使得表面硬度低于标准值,导致扭力杆的强度降低,也引发了扭力杆早期断裂。The causes of early fatigue fracture of 50CrVA torsion bar were analyzed by means of chemical composition analysis,macro and micro fracture analysis,metallurgical analysis and hardness test.The results show that the torsion rod surface was repaired,but the repair welding area has defects such as un-fusion and crack,which becomes fatigue source in the fracture,and is the most important reason for the early fracture of the torsion bar;Mn,Cr,V and other elements in the raw materials are low,which reduces the hardenability and makes the surface hardness lower than the standard value.The low surface hardness reduces the strength of the torsion bar and also leads to the early fracture of the torsion bar.According to the analysis,the improvement measures are proposed.

关 键 词：50CrVA钢 断口 疲劳断裂 补焊 表面硬度 

分 类 号：TG115.5[金属学及工艺—物理冶金]