钢轨闪光焊接工艺与接头落锤试验分析

试验采用YHG-1200TH型移动式钢轨闪光焊机，焊接武钢60 kg/m U71Mn G热轧态钢轨.通过观察分析焊接曲线中闪平、脉动闪光、加速闪光与顶锻保压各阶段电流、电压、钢轨位移、压力等因素，结合接头落锤试验情况，调整并优选出合理工艺参数；分析焊接热输入与顶锻量间的搭配关系及接头抗落锤次数，观察断口与接头显微组织.结果表明，试验用钢轨闪光焊接热输入在11.5~12.5 MJ之间且顶锻量在15~16 mm之间时，接头抗落锤情况较集中，质量稳定性好；合理工艺参数焊接且经落锤检验合格的接头断口无明显缺陷，焊缝及热影响区组织为珠光体和少量铁素体，未见马氏体、贝氏体组织或其它缺陷.

Study on flash butt welding process of rail and joint hammer impact test

The U71Mn G hot rolled rail from Wuhan Iron and Steel(Group) Company was welded by flash butt welding using weld machine of model# YHG-1200^TH. By analyzing the variation of welding current, voltages, displacement, pressure etc., in the welding process with respect to those factors including pre-flash, pulse flash, accelerating flash and upset forging, and combined with the hammer impact test, the study aimed to optimize the welding process parameters. Then analysis on the relations between welding heat input, upset forging and impact numbers was performed. The joint fractured surface and the microstructure were also observed. The study specifically approved that when welding heat input located between 11.5 to 12.5 MJ and upset forging length was inside 15~16 mm, the welded joint can perform well in the hammer impact tests,with good quality and consistency. The fractured surface of the joint welded in optimized parameters had no obvious defects. The microstructure of the weld the heat affected zone are pearlite with a small proportion of ferrite, No martensite, bainite or other defects was found in the weld structure.