几种高强铝合金的激光填粉焊接

采用2500W Nd:YAG激光加工系统,利用填充粉末激光焊接技术进行了几种高强铝合金的焊接;送粉头采取的是一种新型同轴三层结构形式。结果表明,采用He:Ar=4:1左右的混合气作为焊接时的保护气比单纯使用He气和Ar气保护效果好,而试板背面保护气采用He气或Ar气均可。高速摄像显示,采用填充粉末的激光焊接过程比没有填充粉末的稳定,熔池金属表面的波动性小;在优选的焊接工艺规范下,含有AlSi12合金粉末的焊缝没有发现热裂纹。焊接接头的拉伸强度实验显示,采用填充粉末、激光焊接优化工艺参数获得的2219、2024、LF3、6061等铝合金试件断裂都发生在母材一侧;即使焊接性差的7075铝合金,其焊缝正反表面平滑连续、成型良好,无明显外观缺陷。焊缝强度较未填粉时有大幅度提高,达到了母材的78%。

Laser Welding of Some Aluminum Alloys with Powder

The study on the weldability of some aluminum alloys was done by Nd:YAG laser welding process with filler powder, AlSi12. The mixed gas, helium and argon, with a proportion of four to one, as a shielding gas, showed the best protection to welding pool. More stable laser welding process was got and the hot cracking was not found in the bead. The tensile strength of the welding joints of 2219, 2024, LF3 and 6061 aluminum alloys had higher value than that of the base metals and the fracture was happened at the position of substrate side. Even though 7075 aluminum alloy with worse weldability, the value of the tensile strength of it's joint with filler powder (without heat treatment) was 360Mpa and was as 78% value as that of the base metal.