59 mm×100 mm矩形52CrMoV4弹簧扁钢轧制工艺及失效分析  

Rolling process and failure analysis of 59 mm×100 mm rectangular 52CrMoV4 spring flat steel

作　　者：袁林 罗景贤 陈阳 张群琥 刘兵 Yuan Lin;Luo Jingxian;Chen Yang;Zhang Qunhu;Liu Bing(Hunan Hualing Xiangtan Iron and Steel Co.,Ltd.,Xiangtan 441200,China)

机构地区：[1]湖南华菱湘潭钢铁有限公司,湖南湘潭441200

出　　处：《锻压技术》2024年第5期109-114,共6页Forging & Stamping Technology

摘　　要：针对59 mm×100 mm矩形52CrMoV4弹簧扁钢易扭转、尺寸不稳定的问题,进行了孔型设计和轧制工艺优化,并采用化学成分分析、显微组织分析、力学性能试验等方法对发生断裂的弹簧扁钢的失效原因进行了分析。结果表明:材料的化学成分符合要求;力学性能指标中,抗拉强度为1511/1494 MPa、屈服强度为1362/1344 MPa、断后伸长率为11.5%/9.0%、断面收缩率为37.0%/36.5%、表面硬度在42.4~42.9 HRC之间分布;表面脱碳层深度为0.24~0.28 mm,奥氏体晶粒度为7.5~8.0级;未发现大型夹杂物等冶金缺陷;材料经热处理后的主要基体组织为回火索氏体+少量贝氏体;断口起源于表面,疲劳源区域表面存在明显压痕,而其他位置未发现压痕,表明表面压痕是导致材料疲劳寿命降低的直接原因,瞬断区微观形貌为沿晶+撕裂韧窝。For the problems of easy torsion and unstable size of 59 mm×100 mm rectangular 52CrMoV4 spring flat steel,the design of hole pattern and the optimization of rolling process were conducted,and the failure cause of broken spring flat steel was analyzed by the methods of chemical composition analysis,microstructure analysis and mechanical performance test.The results show that the chemical composition of material meets the requirements.In the mechanical performance indicators,the tensile strength is 1511/1494 MPa,the yield strength is 1362/1344 MPa,the elongation after fracture is 11.5%/9.0%,the reduction of area is 37.0%/36.5%,the surface hardness is distributed between 42.4 and 42.9 HRC,the depth of surface decarburization layer is 0.24-0.28 mm,and the austenite grain size is 7.5-8.0 grades.No metallurgical defects such as large inclusions are found,and the main matrix structure of material after heat treatment is tempered martensite+a small amount of bainite.The fracture originates from the surface,and there are obvious indentations on the surface of fatigue source area,while no indentations are found in other positions.Therefore,the surface indentations are the direct cause for the fatigue life of material,and the microstructure of instantaneous fracture zone is intergranular+tearing dimples.

关 键 词：52CrMoV4弹簧扁钢 疲劳寿命 断裂 夹杂物 脱碳层 

分 类 号：TG142.41[一般工业技术—材料科学与工程] TG335.57[金属学及工艺—金属材料]