高速列车侧墙大型材激光-MIG复合焊接

Laser-MIG hybrid welding on the large-size profiles of high-speed train side walls

试验采用激光-MIG复合焊接方法对高速列车6005A铝合金侧墙大型材进行焊接,分析焊接接头的显微组织及力学性能。研究结果表明,焊接接头呈现漏斗状,明显分为两部分,上半部分较宽呈现碗形,下半部分较窄呈现锥形;由焊缝中心至熔合线,Al、Mg元素的含量有所升高;焊缝中心的等轴晶组织均匀细小,熔合线附近的柱状晶组织短小且特征模糊;焊接接头硬度介于54.12~84.02 HV,焊缝和热影响区的软化区是硬度最低的区域,焊接接头热影响区宽约9 mm;焊接接头抗拉强度稳定,平均抗拉强度210 MPa,明显高于常规MIG焊接接头。

Laser-MIG hybrid welding was applied to weld the larger size 6005 A aluminum alloy profiles of high-speed train side walls,microstructure and mechanical properties of welding joint were observed. The results showed that the shape of welding joint was like a funnel,and it could be clearly divided into two parts. The upper half was wide,and its shape appeared a bowl. The lower part was narrow,and its shape appeared a awl. From seam center to fusion line,the element content of Al and Mg was increased. The equiaxed grain structure of seam center was uniform and fine. The columnar grain structure near fusion line was short and its characteristic was fuzzy. The hardness of welding joint was ranged from 54.12 HV to 84.02 HV. Weld and the softening of heat affected zone area had lowest hardness. The width of HAZ was about 9 mm. The tensile strength of welding joint was stable,its average tensile strength was 210 MPa,which was obviously higher than that of conventional MIG welding joint.