外加磁场对高强不锈钢电阻点焊熔核组织与性能调控技术研究  

Study on the Control Technology of Microstructure and Properties of High Strength Stainless Steel Resistance Spot Welding by Applied Magnetic Field

作　　者：徐野 叶结和 李卓然 夏裕俊 李永兵[2,3] 韩晓辉 XU Ye;YE Jiehe;LI Zhuoran;XIA Yujun;LI Yongbing;HAN Xiaohui(CRRC Qingdao Sifang Co.,Ltd.,Qingdao,266111,China;Institute of Vibration,Shock and Noise,Shanghai JiaoTong University,Shanghai 200240,China;State Key Laboratory of Mechanical System and Vibration,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司,山东青岛266111 [2]上海交通大学机械系统与振动国家重点实验室,上海200240 [3]上海交通大学上海市复杂薄板结构数字化制造重点实验室,上海200240

出　　处：《电焊机》2024年第9期55-62,68,共9页Electric Welding Machine

摘　　要：针对轨道车辆高强不锈钢材料电阻点焊存在的压痕明显、熔核直径波动较大、熔核中心缩孔等问题,探索了磁控电阻点焊技术对提升焊接质量和接头性能的潜力。通过在现有电阻点焊设备上增加环形永磁体,利用外加磁场对熔融金属进行电磁搅拌,发现磁控电阻点焊能够显著改善焊点质量和接头性能。与传统电阻点焊相比,磁控点焊可降低凸痕高度80.6%,增大熔核直径12.0%,并将熔核等轴晶区的枝晶间比例从29%改善至6%。此外,磁控点焊接头的拉剪断裂载荷提高11.8%,疲劳强度也得到了提升。通过微观组织观测发现,磁控点焊能够有效细化熔核晶粒,使枝晶间比例大幅下降,从而提高接头表面强度,降低压痕深度。疲劳试验结果表明,磁控点焊接头的疲劳寿命显著提高,且断裂模式由传统点焊的界面断裂转变为高韧性的纽扣断裂模式。研究为磁控电阻点焊技术在不锈钢轨道车辆制造中的应用提供了实验数据支持,并为无涂装车辆高可靠无痕点焊提供了借鉴。This study explores the potential of magnetic resistance spot welding technology to improve the welding quality and joint performance of high-strength stainless steel materials for railway vehicles,which are prone to problems such as prominent indentation,large fluctuations in nugget diameter,and shrinkage holes in the center of the nugget.By adding annular permanent magnets to existing resistance spot welding equipment and utilizing the electromagnetic stirring effect of the external magnetic field on the molten metal,magnetic resistance spot welding was found to significantly improve the quality of the weld and joint performance.Compared to traditional resistance spot welding,magnetic spot welding can reduce indentation height by 80.6%,increase nugget diameter by 12.0%,and improve the dendrite proportion in the isometric zone of the nugget from 29% to 6%.Additionally,the tensile shear fracture load of the magnetic spot welded joints is increased by 11.8%,and fatigue strength is also enhanced.Microstructure observations reveal that magnetic spot welding can effectively refine the nugget grains,significantly reduce the dendrite proportion,thereby improving the surface strength of the joint and reducing indentation depth.Fatigue test results show that the fatigue life of magnetic spot welded joints is significantly improved,and the fracture mode changes from the interfacial fracture of traditional spot welding to a high-toughness button fracture mode.This study provides experimental data support for the application of magnetic resistance spot welding technology in the manufacturing of stainless steel railway vehicles and offers valuable references for the high reliability and mark-free spot welding of unpainted vehicles.

关 键 词：磁控电阻点焊 高强不锈钢 轨道车辆 力学性能 焊接质量 

分 类 号：TG453[金属学及工艺—焊接]