激光热丝焊表面修复成形质量分析和控制

Formation quality analysis and parameters optimization of laser hot wire repair welding

激光热丝焊可精确控制热输入和高效熔覆金属,适合用于表面修复,但缺乏对激光热丝多道修复成形质量的研究.基于响应曲面法(RSM)设计了激光热丝多道修复试验,选取激光功率、扫描速度、送丝速度和搭接率作为变化因子,成形系数、稀释率和未熔合缺陷比率作为响应.结果表明,成形系数、稀释率和未熔合缺陷比率与工艺参数呈二次关系,适当降低送丝速度,提高激光功率、扫描速度和搭接率,有利于获得无未熔合缺陷、稀释率小且表面平整的多道熔覆层.利用重叠等高线图,根据指定的质量要求进行多响应约束,可以预测相应的工艺参数窗口,达到控制激光热丝焊多道修复成形质量的目的.

Laser welding with hot wire addition can precisely control the heat input and therefore it can efficiently clad the metal,which is suitable for surface repairing. There are few reports on the analysis and optimization of weld formation quality of laser hot wire multi-pass repair welding. Based on RSM( response surface methodology),laser power,scanning speed,wire feed rate and overlap ratio were selected as process variables,while surface flatness,dilution rate and incomplete fusion ratio as response parameters. The results indicated that the surface flatness,the dilution rate and the incomplete fusion ratio had a quadratic relation with these variables. Meanwhile,an optimal cladding layer with no incomplete fusion,low dilution rate and good surface flatness was obtained by appropriately reducing the wire feed rate,and increasing the laser power,the scanning speed and the overlap ratio. By using overlap contour,multiple responses were comprehensively optimized according to the specific requirement of formation quality.