Abstract A defect-free welded joint of 100 mm-thick SUS 304 steel plates is produced by ultra-narrow gap laser welding with filler wire in the laser conduction mode in 42 layers. The laser beam concurrent heating of the groove side walls and bottom ensures the adequate side wall fusion, with the angle distortion belowed 1°, and the average fusion ratio of the whole weld of about 11%. The microstructure is composed of cellular grains adjacent to the fusion line and fine equiaxed grains. The average tensile strength of the weld joint is 658 MPa, which corresponds to ∼95% of that of the base metal. The fracture occurs near the fusion line in the cellular grain zone of the weld joint. The microstructure morphology difference in the weld joint implies the uneven distribution of microhardness which values in the equiaxed grain zone significantly exceed those the cellular zone.

中文翻译：

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100mm厚SUS304钢板超窄间隙激光焊接接头的组织和力学性能

摘要 采用激光导通模式填充焊丝超窄间隙激光焊接，制备了100 mm厚SUS 304钢板的42层无缺陷焊接接头。激光束同时加热坡口侧壁和槽底，保证了充分的侧壁熔合，角度畸变小于1°，整个焊缝的平均熔合率约为11%。显微组织由靠近熔合线的蜂窝状晶粒和细小的等轴晶粒组成。焊接接头的平均抗拉强度为 658 MPa，相当于母材抗拉强度的 95%。断裂发生在焊接接头蜂窝状晶粒区的熔合线附近。