钢轨闪光焊接头落锤断裂相关因素及非典型缺陷分析  

Correlative Factors and Atypical Defects Analysis of Drop Hammer Fracture of Rail Flash Butt Welded Joint

作　　者：赵智聪 高文会 倪峥嵘 代韬 ZHAO Zhicong;GAO Wenhui;NI Zhengrong;DAI Tao(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;Beijing Advanced Material Technology Corporation Limited,Beijing 100081,China)

机构地区：[1]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 [2]北京中铁科新材料技术有限公司,北京100081

出　　处：《高速铁路新材料》2024年第4期66-71,共6页Advanced Materials of High Speed Railway

基　　金：中国铁道科学研究院集团有限公司基金项目(2022YJ160)。

摘　　要：在焊轨基地成品台上对钢轨闪光焊接头进行随机取样,并按铁路行业标准相关要求进行落锤试验,统计了落锤断口各类缺陷出现规律、灰斑缺陷的分布规律,分析了落锤结果与母材生产厂家、落锤温度的相关性。同时针对高性能钢轨U22SiMn、U95Cr进行落锤试验,分析了高性能钢轨的非典型缺陷。结果表明:U75V钢轨接头落锤试验性能优于U71Mn钢轨,且灰斑出现概率也低于U71Mn钢轨;导致U71Mn、U75V钢轨接头落锤试验不通过的原因有灰斑面积超标、灰斑露头、过烧、轨底微裂纹,其中灰斑面积超标和灰斑露头影响最大;灰斑缺陷出现的位置和面积都比较集中,其中80%以上出现在轨底角区域,灰斑面积10 mm^(2)以下的接头占出现灰斑接头总数的77%;攀钢钢轨闪光焊接头落锤试验断裂率最低;落锤试验温度在25~35℃范围内落锤断裂率最小;非典型缺陷高熔点夹杂物出现在U71Mn钢轨接头,渗碳体魏氏组织出现在U95Cr钢轨接头,团状马氏体组织出现在U22SiMn钢轨接头。In accordance with the pertinent guidelines of railway standard,this article performed drop hammer experiments and random sampling on the welding rail base's completed product platform.A statistical analysis was performed on the distribution patterns of gray spot defects and the occurrence patterns of different flaws on the drop hammer fracture surface.The relationship among the base material manufacturer,the drop hammer temperature and the drop hammer results was analyzed.Drop hammer tests on high-performance rails(U22SiMn and U95Cr)were carried out concurrently.The unusual welding flaws in high-performance rails were analyzed.The results indicate that the U75V rail joint outperforms the U71Mn rail in the drop hammer test,additionally,there are less gray spots overall than on U71Mn rail;The U71Mn and U75V rail joint drop hammer test failed due to overburning,exposed gray spots,excessive gray spot area,and microcracks at the bottom of the rail.The two that have the biggest effects are the exposed gray spots and the excessive gray spot areas;The location and area of gray spot defects are comparatively concentrated,with 77%of all gray spot joints being found in joints with gray spot area less than 10 mm^(2),and over 80%of them occurring in the track foot area;The flash welded joint of Panzhihua Steel Rail have the lowest fracture rate in a drop hammer experiment.The fracture rate of this experiment is found to be the lowest within a range of 25~35℃.The non-typical defects with inclusions with high melting points occur in the U71Mn rail joints,while the carburized martensite occur in the U95Cr rail joints,the clustered martensite occur in the U22SiMn rail joints.

关 键 词：钢轨焊接 落锤 缺陷 灰斑 过烧 

分 类 号：U213.92[交通运输工程—道路与铁道工程]