超薄不锈钢片的微激光焊接工艺研究

采用微型脉冲激光实现了0.2mm厚321不锈钢片的对接焊,并通过正交优化设计对工艺参数进行了优化,研究了工艺参数对焊接接头微观形貌及组织的影响。结果表明,焊接接头获得最大抗拉力的最优工艺参数是脉冲功率百分比为15、脉冲频率为5Hz、脉冲宽度为2.1ms,此时焊接接头的承载能力达到母材的95%。当微激光焊的脉冲能量过大时会产生热量的积累、导致焊缝发生烧穿,当脉冲宽度较小时激光脉冲的熔透能力较弱、导致焊缝未焊透,这两者都会导致焊接接头的承载能力较差。承载能力较高的焊接接头其显微组织由焊缝中心区的等轴晶和焊缝边缘细小的柱状晶组成。

Study on the Micro Laser Welding Parameter of Ultrathin Stainless Steel Sheet

Butt welding of 0.2mm thick 321 stainless steel sheet was realized using micro impulse laser.The processing parameters were optimized by orthogonal experimental and influence of processing parameter on the morphology and microstructure of welded joint was studied.The results show that the optimized processing parameters that can get the maximum stretching resistance are:pulse power percentage is 15,pulse frequency is 5 Hz and pulse width is 2.1ms.With the optimized processing parameters,the stretching resistance of the welded joint can achieve 95% of base metal.Burn through in welded seam is easy to occur when laser pulse energy is too big and nonpenetration occurs when pulse width is too small.Both burn through and nonpenetration can lead to the decrease of stretching resistance.The microstructures of welded joint that has best stretching resistance are composed of equiax crystals in weld center and fine columnar crystals in weld edge.