铝青铜水下湿法激光焊接焊缝成形与力学性能

Weld Forming and Mechanical Properties of Aluminum Bronze Underwater Wet Laser Welding

为解决湿法焊接焊缝质量不高的问题,对铝青铜材料展开水下湿法激光焊接实验,利用扫描电子显微镜(Scanning Electron Microscope,SEM)、显微硬度仪、万能试验机分别检测和分析了焊接接头的微观组织和力学性能。结果表明:铝青铜水下湿法焊接会出现大量气孔,水深增加会导致气孔增多,提高焊接速度可以改善焊缝成形质量,通过在基体表面预置自蔓延粉末能够有效减少气孔;焊缝中上部为胞状晶组织,底部为发达的树枝晶;焊缝平均硬度为240 HV,与基体相比提高了50%;拉伸试验试件均断裂在焊缝处,平均拉伸强度为235 MPa,为基体的43%。

In order to solve the problem of low quality of wet welding seam,the experiment of underwater wet laser welding of aluminum bronze is carried out.The microstructures and mechanical properties of the welded joints are tested and analyzed by Scanning Electron Microscopy(SEM),microhardness tester and universal testing machine respectively.The results show that a large number of pores appear in underwater wet welding of aluminum bronze,the increase of water depth leads to the increase of pore.And the increase welding speed can improve the forming quality of welds.Self-propagating powder is placed on the substrate surface which can effectively reduce the pore produced by wet welding.The upper part of the weld is cellular crystal and the bottom is dendrite crystal.The average hardness of the weld is 240 HV,which is half higher than that of the matrix.The average tensile strength is 235 MPa,which is 43%of the matrix.