Study on laser repair welding to brazing bead of 6063 aluminum alloy

As for precise components of aluminum alloy by brazing, the tradition techniques, such as electronic beam welding and TIG/MIG, are not suitable for repairing the defects which were found in the brazing seam during the brazing process. Laser may be the best one of all heat sources because of its advantages, like high energy density, low heat input, well flexibility and controlling. In this paper, the influence to the stability of laser welding process caused by the brazing flux was studied. By adopting optimized parameters, the butt joint samples of 6063 aluminum alloy plate with the thickness of 3.0mm made by vacuum brazing process, which had had the groove with different depth on the original brazed joint by milling, were used in the experiments by laser welding with filler wire. The results showed that some elements of flux remained in brazing seam were the main factor to influence the stability of laser welding process. For the brazing seam with the groove depth of 2.0mm, laser welding with filler wire could restrain the harmful impact of elements in the welding process. The weld with the surface of clean, smooth and without pore was gained by laser welding with filler wire, as same as the result when brazing seam was completely removed.