钢轨铝热焊接砂型及焊接工艺优化

Optimization of Sand Mold and Welding Process Optimization of Rail Thermit Welding

用于钢轨铝热焊接的ZTK-1型砂型焊后残余冒口棒打磨量大,打磨用时久,焊后接头在轨腰及以下部位溢流飞边严重。针对这一问题,将砂型轨底角根部优化为两个尺寸8.5 mm×12.5 mm的方冒口。通过数值模拟、预热试验检验砂型预热效果,通过焊接试验、力学性能检测确定焊接工艺。结果表明:优化后的砂型预热效果良好,焊接工艺为预热时间240 s,推瘤后60 s去除冒口棒,焊后接头残余冒口棒打磨量降低54%,溢流飞边打磨时间降低16%,能更好地适用于天窗点铝热焊接作业。

ZTK-1 sand mold used for rail thermit welding has a large amount of grinding of residual riser bar after welding,takes a long time,and the overflow flash of welded joint at and below the rail waist is serious.To solve this problem,the bottom corner root of sand mold rail is optimized to two sizes of 8.5 mm×12.5 mm square riser.The preheating effect of sand mold is tested by numerical simulation and preheating test,and the welding process is determined by welding test and mechanical property test.The results show that the optimized sand mold preheating effect is reasonable.The welding process is that the preheating time is 240 s,the riser bar is removed 60 s after tumor pushing,the grinding amount of joint residual riser bar after welding is reduced by 54%,and the grinding time of overflow flash is reduced by 16%,which is better suitable for spot thermit welding of maintenance time window.