高速列车底板型材激光-熔化极惰性气体保护复合焊接试验

Laser-MIG Composite Welding Test of Bottom Plate Profile of High-speed Train

进行高速列车铝合金底板型材激光-熔化极惰性气体保护复合焊接试验,对焊接接头的硬度、形貌、力学性能、显微组织进行分析。结果表明,焊接接头内部熔合良好,无气孔缺陷,焊缝形状狭长,呈上宽下窄形貌。焊接接头平均抗拉强度为230 MPa,达到母材强度的73.5%,拉伸断裂于热影响区。焊缝和热影响区软化区是焊接接头的薄弱部位。受激光焊接作用,焊缝组织为等轴晶和柱状晶,组织分布均匀且细小。

The laser-metal inert gas composite welding test of aluminum alloy bottom plate profile of high-speed train was carried out,and the hardness,morphology,mechanical property and microstructure of the welded joint ware analyzed.The result shows that the internal fusion of the welded joint is good,there is no porosity defect,and the shape of the weld is narrow and long,with a wide upper and narrow lower morphology.The average tensile strength of the welded joint is 230 MPa,which reaches 73.5%of the strength of the base metal,and the tensile fracture is in the heat-affected zone.The weld and the heat-affected zone softening zone are the weak points of the welded joint.Under the action of laser welding,the weld structure is equiaxed and columnar,and the structure is evenly distributed and fine.