中国激光, 2014, 41 (1): 0103004, 网络出版: 2013-12-24
SUS301L不锈钢CO2激光-MIG复合焊接头组织性能研究
Mircostructure and Performance of CO2-MIG Hybrid Welding of SUS301L Stainless Steel
激光技术 复合焊 SUS301L不锈钢 组织性能 装配间隙 laser technique hybrid welding SUS301L stainless steel microstructure and performance assembly gap
摘要
针对2 mm厚SUS301L奥氏体不锈钢薄板进行CO2激光熔化极惰性气体保护电弧(MIG)复合对接焊试验,深入分析了焊接接头不同区域的显微组织及相组成,研究了装配间隙对焊接接头微观组织和力学性能的影响。结果表明,SUS301L奥氏体不锈钢复合焊接接头中心区域呈一定方向性的细小枝晶组织,未出现等轴晶区域,偏离焊缝中心区为垂直于熔合线向焊缝中心生长的柱状晶组织,距焊缝中心距离越远,晶粒越粗大;焊接接头主要由γ奥氏体相和少量δ铁素体相组成,焊缝凝固模式为铁素体奥氏体结晶(FA)模式,凝固过程中发生的δ-γ转变由块状转变和相界面处的短程自由扩散作用共同完成;随着装配间隙的增大,焊缝残余δ铁素体含量逐渐降低,抗拉强度随之下降,断裂发生在焊缝靠近熔合线区域的粗大柱状晶区。
Abstract
SUS301L stainless steel sheet with thickness of 2 mm is welded using CO2 laser-metal inert gas arc (MIG) hybrid welding. The microstructure and phase composition of joint are analyzed in detail. Furthermore, the influence of assembly gap on weld microstructures and performance is investigated. Results indicate that the joint is composed of fine dendritic structure in the weld center and columnar crystals far away from the center zone. And the columnar crystals are found growing perpendicularly to the fusion line. Grain size increases with the distance from the center of weld. Phase composition in the joint is identified as γ austenite and a little δ ferrite. The solidification type of weld is dominated by ferrite-austenite (FA) mode and the transformation from δ to γ is dominated by massive transformation and short range free diffusion. With the increase of assembly gap, residual δ content and tensile strength of weld decrease gradually. The fracture occurs at the area of coarse columnar grain near the fusion line.
陈洋, 吴世凯, 肖荣诗. SUS301L不锈钢CO2激光-MIG复合焊接头组织性能研究[J]. 中国激光, 2014, 41(1): 0103004. Chen Yang, Wu Shikai, Xiao Rongshi. Mircostructure and Performance of CO2-MIG Hybrid Welding of SUS301L Stainless Steel[J]. Chinese Journal of Lasers, 2014, 41(1): 0103004.