铝合金焊前激光清洗工艺研究及接头性能评估

Study on laser cleaning process before welding of aluminum alloy and evaluation of joint performance

针对铝合金焊前激光清洗,以表面氧含量为指标,研究平均功率、扫描频率对清洗效果的影响,以表面硬度、表面耐腐蚀性评价其服役性能,最终获得高质量剥离铝合金表面氧化膜的工艺窗口,确定有损/无损激光清洗边界条件,对激光清洗与人工打磨进行全方位对比,最终显示两者的作用效果差异。结果表明,在平均功率125~175 W,扫描频率100~150 Hz范围内可实现铝合金氧化膜的高质量剥离;当激光清洗功率密度为(2.24~3.14)×10^(6)W/cm^(2)时,可实现无损激光清洗,当激光功率密度>3.14×10^(6)W/cm^(2)时,即为有损激光清洗;焊前进行激光清洗可全面提升焊缝质量,接头强度可达281.4 MPa,可有效替代人工打磨。

For the laser cleaning of aluminum alloy before welding,the effects of average power,scanning frequency on the cleaning effect were studied with the surface oxygen content as the index. The service performance was evaluated by surface hardness and surface corrosion resistance. Finally,the process window of high-quality stripping of aluminum alloy surface oxide film was obtained. And the destructive/non-destructive laser cleaning boundary conditions were determined. The comprehensive comparison between laser cleaning and manual grinding was carried out. And the difference in the effect of the two was finally shown. The results showed that the high quality stripping of aluminum alloy oxide film could be achieved in the range of average power 125 ~ 175 W,scanning frequency 100 ~ 150 Hz. When the laser cleaning power density was( 2. 24 ~ 3. 14) × 10^(6) W/cm^(2),non-destructive laser cleaning could be realized. When the laser power density was greater than 3. 14×10^(6) W/cm^(2),it was a lossy laser cleaning. Laser cleaning before welding could comprehensively improve the weld quality. The joint strength could reach 281. 4 MPa. Laser cleaning could effectively replace manual grinding.