6061铝合金激光深熔焊等离子体光谱特征与气孔的相关性

Correlation between plasma spectral characteristic and porosity during laser deep penetration welding of 6061 aluminum alloy

采用光纤激光器对6061铝合金进行焊接,获得了表面成形良好的焊缝.利用光谱仪和高速摄像机获取等离子体的光谱和图像,分析了激光深熔焊时等离子体的光谱特征,讨论了光谱强度及其波动程度与焊缝气孔的位置及气孔率之间的相关性.结果表明,6061铝合金激光深熔焊时等离子体的电离度低,光谱中只有金属原子谱线,Al I 396.152 nm谱线的强度能够反映焊接过程中等离子体的光谱特征;等离子体光谱强度及其波动程度与焊缝中氢气孔的形成位置和气孔率均不存在必然联系;等离子体光谱强度与小孔型气孔的位置不存在相关性,但其波动程度能够反映小孔型气孔的气孔率.

6061 aluminum alloy weld with good appearance was obtained by using fiber laser. The spectrometer and high-speed camera were applied to acquire plasma spectrum and dynamic image respectively,the plasma spectral characteristic was analyzed,and the correlation between spectral intensity with its fluctuant degree and the location of porosity with its percentage were discussed during laser deep penetration welding of the aluminum alloy. The result shows that the degree of plasma ionization is low,and there is only metal atomic spectral lines during the laser deep penetration welding of aluminum alloy. The intensity of Al I 396. 152 nm spectral line can indicate the plasma spectral characteristic of welding process. There is not the necessary relationship between the intensity of plasma spectrum with its degree and the location of hydrogen porosity with its percentage in aluminum alloy weld. Furthermore,there is no correlation between the intensity of plasma spectrum and the location of keyhole porosity,but the fluctuant degree of plasma spectral intensity can indicate the percentage of keyhole porosity.