20Mn2A起重链条异常断裂原因分析  

Cause analysis of abnormal fracture of 20Mn2A lifting chain

作　　者：路晨龙 高晓伟 李玉岗[1] 王忠伟[1] LU Chenlong;GAO Xiaowei;LI Yugang;WANG Zhongwei(Tianjin Rockcheck United Steel Group Co.,Ltd.,Tianjin 300352,China)

机构地区：[1]天津荣程联合钢铁集团有限公司,天津300352

出　　处：《天津冶金》2022年第5期70-73,共4页Tianjin Metallurgy

摘　　要：起重链条是提升重物不可缺少的起重索具,它对材料性能有特殊要求。要求热轧盘条在加工编链冷变形时具有较高的塑性、可焊性和淬透性,以满足链条加工成型和热处理后机械性能的要求。合金结构钢20Mn2A线材在冷变形过程中具有较高的塑性,与相应含碳量的碳钢相比,具有较高的淬透性,适用于起重链条材料。本文研究了几种断裂强度不足的起重链条的失效现象,从原材料质量和加工工艺上找出了问题的原因,结合链条破断部位化学成分、金相组织、断口形貌等检测分析结果,指出预处理不当造成表面脱碳、原料成分变化及机械损伤等是引起链条机械性能降低的主要原因,并相应地制定了改进措施。The lifting chain is an indispensable lifting rigging for lifting heavy objects,it has special requirements for material performance.The hot rolled wire rod is required to have high plasticity,weldability and hardenability when processing cold deformation of braided chain,so as to meet the requirements of machine-shaping of the lifting chain and mechanical properties after heat treatment.The alloy structural steel 20Mn2A wire rod has high plasticity during cold deformation,compared with carbon steel with corresponding carbon content,it has higher hardenability and is suitable for the material of lifting chain.This paper studies the failure phenomenon of several lifting chains with insufficient fracture strength,looking for problems the cause of the problem from the raw materials quality and processing technic,based on the test and analysis results of chemical composition,metallographic structure and fracture morphology of the fracture part of the chain,it is pointed out that the surface decarburization caused by improper pretreatment,raw material composition change and mechanical damage are the main reasons for the reduction of the mechanical performance of the chain,and the improvement measures are formulated accordingly.

关 键 词：起重链条 断裂强度 脱碳 化学成分 机械损伤 

分 类 号：TG115[金属学及工艺—物理冶金] TH21[金属学及工艺—金属学]