超薄不锈钢片微激光焊接的焊缝成形

Weld shaping for ultrathin stainless steel sheet by micro laser welding

采用微型脉冲激光实现了0.2mm厚321不锈钢片的对接焊,研究了脉冲频率、脉冲宽度和脉冲功率等工艺参数对焊缝成形的影响规律。结果表明,0.2mm厚321不锈钢片的微激光对接焊容易在焊缝处产生烧穿,在收弧处形成较深的弧坑。在其它工艺参数固定不变时,减小脉冲频率和脉冲宽度均可以减少或避免焊缝的烧穿,改善焊缝成形;减小脉冲功率有利于避免焊缝收弧处较深弧坑的形成,但脉冲功率过小会导致未焊合。当脉冲功率分数为12%时,脉冲频率在较宽的范围内变化都能获得成形良好、无缺陷的焊接接头。焊缝组织由中心部位的等轴晶和边缘细小的柱状晶组成,在焊缝和母材的交界处几乎不存在焊接热影响区。

Butt welding of 321 stainless steel sheet with thickness of 0.2 mm was realized by micro impulse laser, and the influence of process parameters such as laser pulse frequency, pulse width and pulse power on weld shaping of the steel was studied. The results show that burn through in welded seam and deep crater in arc stopping area are easy to occur when 321 stainless steel sheet with thickness of 0.2 mm is welded by micro impulse laser. When other parameters are fixed, decreasing pulse frequency and pulse width can avoid or decrease burn through and improve weld shaping; decreasing pulse power is propitious to avoid deep crater generating in arc stopping area. But incomplete penetration will occur when pulse power is too small While pulse power percentage is 12% , welded joints with good shaping and without weld defect can obtain within the wide pulse frequency range. Weld microstructure is composed of equiaxed crystals in weld center and fine columnar crystals in weld edge. There is almost no heat-affected zone at the edge between welded seam and base metal.