两种焊接工艺下过共析钢轨接头的冲击磨损性能  

Impact Wear Properties of Hypereutectic Rail Joints Welded by Two Welding Processes

作　　者：李炜[1] 宋伟军 戴安 常凯荣 白威 LI Wei;SONG Weijun;DAI An;CHANG Kairong;BAI Wei(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学材料先进技术教育部重点试验室,四川成都610031

出　　处：《西南交通大学学报》2021年第2期403-410,共8页Journal of Southwest Jiaotong University

基　　金：国家重点研发计划(2017YFB0304500)。

摘　　要：为研究闪光焊、铝热焊两种焊接工艺下过共析钢轨焊接接头的冲击损伤演变行为以及性能差异,在自制的冲击磨损试验机上对过共析钢轨焊缝、热影响区软化部位及母材进行了不同冲击次数下的模拟实验.研究结果表明:随着冲击次数的增加,钢轨焊接接头的冲击磨损均经历着塑性变形、点蚀破坏和疲劳剥落的过程,冲击损伤是疲劳磨损和氧化磨损共同作用的结果;由于焊接工艺导致的接头组织结构和力学性能的差异,热影响区软化部位冲击时塑性变形最严重,磨损体积和磨损率最大,抗冲击性能最差;由于对闪光焊焊接接头进行了焊后正火热处理,其组织结构及抗冲击性能明显优于铝热焊;硬度对焊接接头的抗冲击性能有显著影响,硬度越高,抗冲击性能越好,疲劳剥落出现的时间越晚.In order to study the impact damage evolution behavior and the impact performance difference of the hypereutectic rail welding joints welded by flash welding and aluminothermic welding,the impact simulation experiments of the hypereutectoid rail welding seam,the softening part of heat-affected zone and the base metal under different impact cycles were carried out by using a self-made impact wear tester.The results show that the impact wear of the rail welded joints underwent the processes of plastic deformation,pitting failure and fatigue spalling with the increasing impact cycles,and the impact damage is the result of combined action of fatigue wear and oxidation wear.Due to the differences in joint microstructure and mechanical properties caused by different welding processes,the softening part of the heat-affected zone exhibited the most severe plastic deformation,the largest wear volume and wear rate,and the worst impact resistance.The microstructure and impact resistance of the flash welding joint are better than those of the aluminothermic welding joint because of the normal heat treatment after welding.Hardness has a significant effect on the impact resistance of welded joints.The higher the hardness,the better the impact resistance and the later the fatigue spalling.

关 键 词：过共析钢轨 闪光焊 铝热焊 冲击磨损 疲劳剥落 

分 类 号：TH117[机械工程—机械设计及理论]