固定闪光焊接头轨底过热区微裂纹产生原因及控制措施  

Causes and Control Measures of Rail Bottom Weld Micro Crack of Stationary Flash Butt Welded Joint

作　　者：杨其全 吕晶 丁韦 王晨阳 赵曦 周华 YANG Qiquan;LYU Jing;DING Wei;WANG Chenyang;ZHAO Xi;ZHOU Hua(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;The Engineering and Railway Signal Overhaul Department of China Railway Beijing Group Co.,Ltd.,Beijing 100071,China;The Engineering Machinery Department of China Railway Jinan Group Co.,Ltd.,Jinan Shandong 250022,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]中国铁路北京局集团有限公司北京工电大修段,北京100071 [3]中国铁路济南局集团有限公司济南工务机械段,济南250022

出　　处：《高速铁路新材料》2023年第1期67-73,共7页Advanced Materials of High Speed Railway

基　　金：中国国家铁路集团有限公司科技研究开发计划项目(J2020G002)。

摘　　要：针对固定闪光焊接头轨底过热区微裂纹问题,通过逐层磨削、超声波探伤、金相检验的试验方法对3种不同状态的固定闪光焊接头进行检验与分析,明确固定闪光焊接头轨底微裂纹的产生原因并提出控制措施。结果表明:接头轨底下表面存在的微裂纹缺陷是引起固定闪光焊接头轨底轻伤的原因;微裂纹是在推凸过程中产生的推凸裂纹,探伤得到的伤损严重程度与微裂纹的总体积及分布密度相关;增大推凸余高、提高焊接热输入、增大顶锻力、提高母材的纯净度和均质化程度均可以有效降低轨底微裂纹的严重程度,但要结合操作的复杂程度和成本进行综合考虑。Aiming at the problem of rail bottom weld micro cracks of stationary flash butt welded joint,the test methods of layer by layer grinding,ultrasonic testing and metallographic examination were used to inspect and analyze the three different states of the stationary flash butt welding joint,so as to clarify the causes of rail bottom weld micro cracks of stationary flash butt welded joint and put forward the control measures.The results show that the micro cracks on the bottom surface of the joint are the cause of the rail bottom weld minor defect of stationary flash butt welded joint.Micro cracks are generated in the process of weld seam shearing.The minor defect severity of ultrasonic testing is related to the total volume and distribution density of micro cracks.The severity of rail bottom weld minor defect can be effectively reduced by increasing the residual height of welding collar during weld seam shearing,increasing the welding heat input,the upsetting force,and improving the purity and homogenization degree of base metal.But it should be considered comprehensively in combination with the complexity of operation and cost.

关 键 词：固定闪光焊 焊缝 轻伤 微裂纹 推凸 

分 类 号：U213.46[交通运输工程—道路与铁道工程]