U75VH热处理钢轨气压焊头正火工艺研究  

Study on Normalizing Process to Improve the Performance of U75VH Heat Treated Rail Joint After Gas Pressure Welding

作　　者：费俊杰 李强 史正鹰 周剑华 蔡小龙 李闯 欧阳珉路 FEI Junjie;LI Qiang;SHI Zhengying;ZHOU Jianhua;CAI Xiaolong;LI Chuang;OUYANG Minlu(Central Research Institue(Qingshan),Baosteel Cooperation,Wuhan Hubei 430080,China;China Railway Lanzhou Bureau Group Co.,Ltd.,Lanzhou Gansu 730050,China;Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]宝钢股份中央研究院(青山),武汉430081 [2]中国铁路兰州局集团有限公司兰州工务机械段,兰州730050 [3]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081

出　　处：《高速铁路新材料》2022年第1期48-52,共5页Advanced Materials of High Speed Railway

摘　　要：钢轨经气压焊接后,为提高焊头性能,需进行焊后正火热处理,针对U75VH热处理钢轨气压焊头正火后,焊头硬度偏低以及焊缝出现马氏体异常组织等问题,开展了U75VH热处理钢轨气压焊头正火工艺研究,结果表明:随着正火加热温度和喷风压力升高,焊头硬度提高,软化区宽度减小;而随着喷风时间缩短,焊缝马氏体组织减少。通过正火工艺优化后,气压焊头的踏面硬度Hj/Hp值为0.95,纵断面洛式硬度H_(j)/H_(p)值为0.93,焊缝组织为珠光体和少量铁素体,焊缝各部位晶粒度为8.0~9.5级,各项性能指标均满足TB/T 1632.4—2014标准要求。In order to improve the performance of the welding joint,normalizing heat treatment is required after gas pressure welding.Aiming at the problems of low hardness and abnormal martensite structure in the weld line of U75VH heat treated rail joint after gas pressure welding,the normalizing process of U75VH heat treated rail joint after gas pressure welding was studied,the results showed that with the increasing of normalizing temperature and air jet pressure,the hardness of welding joint increased and the width of softening zone decreased,with the shortening of air spraying time,the martensite of welding joint decreased.The Brinell hardness ratio of joint surface to the base material was 0.95,the Rockwell hardness ratio of joint vertical section to the base material was 0.93,the weld line microstructure was pearlite and a small amount of ferrite,grain size was grade 8.0~9.5,and other performance indexes of welding joint meet the requirements of standard of TB/T 1632.4―2014.

关 键 词：U75VH热处理钢轨 气压焊接 焊头性能 正火工艺 

分 类 号：TG156.4[金属学及工艺—热处理]