奥氏体不锈钢丝激光焊接头的组织与力学性能

Microstructure and mechanical properties of austenite stainless steel wire joints welded by laser

采用脉冲激光焊技术连接奥氏体不锈钢细丝.利用光学显微镜、扫描电镜等分析测试手段,研究了不锈钢丝激光焊接头的微观组织特点及激光焊参数对接头组织与力学性能的影响规律.结果表明,焊缝金属由奥氏体胞状晶和胞状树枝晶构成,热影响区主要为等轴晶,且过热区晶粒明显粗化.随着激光脉冲能量和脉冲宽度的增加,焊缝熔透率及熔宽增加,焊缝及热影响区组织有粗化的趋势.小的脉冲宽度(2,3ms)对于保证不锈钢丝焊接质量的稳定性是不利的.激光焊接头抗拉强度最大值为680MPa(脉冲宽度10ms,脉冲能量7.6J),焊缝中心区是焊接接头最薄弱的部位.

Austenite stainless steel thin wires were joined by using pulsed YAG laser welding.The microstructural characteristics and influences of laser welding parameters on microstructures and mechanical properties of joints were investigated by means of optical microscopy and scanning electronic microscopy et al.Experimental results show that the fusion zone features cellular and cellular-dendrite crystal structure,HAZ mainly exhibits equiaxed crystals,and near the fusion zone the equiaxed crystals coarsen.With the increase of power input and pulse duration for laser,the penetration ratio and melted metal width increase,and microstructures of the weld metal and HAZ have coarsening tendency.It is unfavorable to select short pulse duration(2 ms,3 ms)for controlling welding quality.The highest tensile strength of laser-welded joints reaches to 680 MPa(pulse duration of 10 ms and power input of 7.6 J),the weld centre being the weakest region in the joints.