高强铝合金激光粉末焊接过程

采用CO2激光(slab)系统进行了高强铝合金的激光填粉焊接,分析了激光与粉末相互作用的5个阶段过程;研究了填充合金粉对CO2激光焊接功率阈值、焊缝成形和焊接过程稳定性的影响.试验表明,合金粉末可以提高焊接过程中激光能量的有效利用率;激光深熔焊接时的临界功率密度明显降低,粉末束流只有作用在光致等离子体的恰当区域才能有效地进入熔池;在一定送粉量下,匹配适当的功率密度和热输入,才能保证得到理想的焊缝.高速摄像图片显示了激光支持的燃烧波及焊接中的过程孔洞,并且合金粉末还可以减弱等离子体的膨胀跳动,有利于获得较为稳定的焊接过程和理想的焊缝成形.

CO2 laser welding process of aluminum alloy with filler powder

The experiments were carried out with CO_2 (slab) laser. The five stages of the inter actions between laser and powder in the laser welding with powder were analyzed. The influences of the filler metal powder on the laser power density threshold value, weld formation and process stability were studied during CO_2 laser welding of aluminum alloy. The experiment results demonstrate that the addition of the metal powder enhances the energy coupling efficiency and reduces the power density threshold value during laser deep welding. Such as the reducing rate is about 50% for A2219 alloy.The experiment results also indicate that the powder can enter the weld pool availably only the powder was delivened to the suitable area after laser beam at the surface of a part.The proper quantity of the alloy powder must match with the right power density and energy input,which can assure to obtain good weld appearance. Meanwhile, the addition of the powder can reduce the fluctuation of the laser-induced plasma and maintain its stability effectively in the laser welding. So a stable welding process and good weld appearance can be obtained in the experiments.