钢轨对接超窄间隙焊接试验

Ultra-narrow gap butt welding of steel rail

利用焊剂带约束电弧超窄间隙焊接方法,对U71Mn钢轨对接进行了探索性试验研究。使用H08Mn2Si焊丝,通过34层焊道将坡口间隙约4 mm的钢轨焊接完成,单层焊接线能量为0.6 kJ/mm。试验表明焊前预热温度大于400℃可有效消除冷裂纹。在不预热的情况下,这种超窄间隙焊接接头热影响区和焊缝的硬度较高;预热可使焊缝硬度下降到与母材相当,同时使热影响区硬度略有下降。

A tentative investigation on butt welding of U71Mn steel rail was carried out by ultra-narrow gap welding with arc-constricting flux strip.The rail joint with groove gap of nearly 4 mm were obtained by weld bead of 34 layers and H08Mn2Si wire as the filler material,and the heat input of single weld bead was 0.6 kJ/mm.The results showed that preheating over 400℃before welding can eliminate cold cracking effectively. Without preheating,the hardness of heat-affected zone and that of welds were higher in this ultra-narrow gap welded joint;and with preheating, the hardness of welds can be lower to be equivalent to the level of the base metal,and the hardness of heat-affected zone can also be decreased slightly.