The aim of this work is to improve the fracture ductility of non-penetrating laser-welded lap joints. The 1.5 + 2.0 and 2.0 + 2.0 lap plates of cold-rolled 301LN stainless steel tilted 15° in the load direction and in the reverse load direction were welded by a vertical laser beam to prepare a positive-tilt weld (PTW) and negative-tilt weld (NTW). The tilt weld had a regular geometry, and the solidification centerline was tilted by approximately 15°. The laser-welded 301LN stainless steel was solidified by the primary ferritic mode with good resistance to thermal cracking, and the weld metal with ultrafine grains had excellent plasticity. The main weld in the penetrating plate of the NTW joints has a greater bending moment than that of PTW joints under tensile loading conditions, so the plastic deformation of the NTW is due to uniform bending, while that of the PTW is due to approximate parallel stretching. The bending deformation of the main weld of the NTW joint leads to a greater tensile stress ratio (decomposed normal stress to shear stress) in the interfacial weld metal than that of the PTW joint, so the interfacial fracture ductility of NTW joints is much greater than that of PTW joints.

这项工作的目的是提高非穿透性激光焊接搭接接头的断裂延展性。通过垂直激光束焊接在载荷方向和反向载荷方向倾斜15°的1.5 + 2.0和2.0 + 2.0搭接的冷轧301LN不锈钢板，以制备正倾斜焊缝（PTW）和负向倾斜焊缝倾斜焊（NTW）。倾斜焊缝具有规则的几何形状，并且凝固中心线倾斜大约15°。激光焊接的301LN不锈钢通过一次铁素体模式凝固，具有良好的抗热裂性，并且具有超细晶粒的焊接金属具有出色的可塑性。在拉伸载荷条件下，NTW接头的贯穿板中的主焊缝的弯矩比PTW接头的主弯矩大，因此NTW的塑性变形归因于均匀的弯曲，而PTW的归因于近似平行拉伸。NTW接头主焊缝的弯曲变形导致界面焊缝金属中的拉伸应力比（分解为正应力与剪切应力）比PTW接头大，因此NTW接头的界面断裂延展性远大于PTW接头。 PTW关节。