紫铜激光扫描焊接焊缝形貌及微观组织研究

Study on Morphology and Microstructure of Pure Copper Laser Scanning Welding Joint

采用IPG单模光纤激光器对T2紫铜进行激光扫描焊接试验,对比分析单面焊不同焊接速度、焊接次数以及双面焊等工艺参数下焊缝的表面形貌、截面形状及微观组织。结果表明:焊接速度对紫铜激光焊接的外观成形影响较大,当焊接速度为10 mm/s时,试样焊缝表面鱼鳞纹均匀细密且连续平整,驼峰、飞溅等缺陷明显减少。焊接接头的微观组织主要为焊缝区的细小等轴晶与熔合区的粗大柱状晶,随着焊接速度的增大,等轴晶区域变窄,且晶粒变细小。与单面单次焊试样相比,单面重复焊接试样焊缝熔宽、熔深均有所增大,但易出现局部热损伤,同时焊缝区晶粒变粗大;采用双面焊接时,试样焊缝表面成形质量不佳,焊缝底部熔合区域出现气孔等缺陷,接头区域晶粒粗大。

IPG single-mode fiber laser was used to conduct laser scanning welding test for T2 copper,and the weld surface morphology,cross-section shape and microstructure of the samples under different welding speeds,welding times in single side welding and double-sided welding and other process parameters were compared and analyzed.The results show that the welding speed has a great influence on the appearance of laser welding of copper.When the welding speed is 10mm/s,the fish-scale lines on the weld surface of the sample are uniform,fine and continuous,and the defects such as hump and splash are significantly reduced.The microstructure of the welded joints is mainly fine equiaxed grains in the weld zone and coarse columnar grains in the fusion zone.With the increase of welding speed,the equiaxed grain zone in the weld become narrower and the grains become finer.The weld width and weld depth of the single-side rewelding sample increase compared with those of the single-side single welding sample,but local thermal damage is easy to occur,and the grains in the weld area of the sample become coarser.When double-sided welding is used,the weld surface forming quality of the sample is poor,the fusion area at the bottom of the weld has pores,and the grains in the joint area are coarse.