异种钢轨气压焊接头的显微组织与力学性能  

Microstructure and Mechanical Properties of Dissimilar Steel Rail Gas Pressure Welded Joint

作　　者：唐充 戴虹[1] 谢航 TANG Chong;DAI Hong;XIE Hang(College of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031

出　　处：《电焊机》2022年第12期28-35,共8页Electric Welding Machine

基　　金：国家重点研发计划(2017YFB4501)。

摘　　要：贝氏体钢轨的焊接性问题导致其应用被制约,为适应贝氏体钢轨在轨道铺设与维护工程中的应用发展趋势,采用气压焊方法研究贝氏体钢轨(U20Mn)与珠光体钢轨(U95Cr)异种钢轨的焊接性。通过光学显微镜(OM)、扫描电镜(SEM)、冲击和拉伸试验探索焊缝界面的微观组织形貌、元素扩散规律和力学性能。结果表明:贝氏体与珠光体异种钢轨焊接接头焊缝界面金属能在固态条件下形成共同晶粒,实现了良好的冶金结合,轨底脚相对其他部位结合程度较差;U20Mn侧焊缝区域主要由马氏体(66.2%)及贝氏体铁素体(33.8%)组成,最高硬度值为500 HB;接头冲击韧性较低,为4.1 J,抗拉强度为961 MPa,延伸率为8%,接头强度较U95CrWZ软化区更高。The application of bainite rail is restricted due to its weldability. In order to adapt to the application and development trend of bainite rail in track laying and maintenance engineering, the weldability of dissimilar steel welding between bainite rail and pearlite rail is studied by pneumatic welding method.The microstructure morphology, element diffusion law and mechanical properties of the weld interface were investigated by optical microscope(OM), scanning electron microscope(SEM), impact and tensile tests. The results show that the weld interface metal of dissimilar steel welded joints of bainite rail and pearlite rail can form common grains in solid state, which can achieve good metallurgical bonding, and the bonding degree of rail foot is poor compared with other parts. U20Mn WZ(U20Mn side weld) area is mainly composed of martensite(66.2%) and bainite ferrite(33.8%), and the highest hardness value is 500 HB;the impact toughness of the joint is4.1 J;the tensile strength is 961 MPa,and the elongation is 8%.

关 键 词：气压焊 U20Mn/U95Cr异种钢焊接 显微组织 力学性能 

分 类 号：TG453[金属学及工艺—焊接]