为了保证船舰在海水环境中拥有足够的焊接强度和耐久性, 选用船用铝合金(5083-O)进行焊接试验, 模拟焊接接头在海水中的耐腐蚀性能。采用高适应性的激光-熔化极惰性气体保护焊复合焊接系统, 分别分析研究了激光功率、焊接电流、光丝距对铝合金焊接接头耐腐蚀性能的影响; 利用型号为CHI760D三电极化学工作站对不同焊接工艺参量下的铝合金焊接接头进行了腐蚀测试。结果表明, 自腐蚀电流密度随激光功率的增加呈先增大后减小再增大的趋势, 随焊接电流和光丝距的增加均呈“V”形规律变化, 即先减小后增大的趋势;当激光功率为3.0kW、焊接电流为200A、光丝距为3mm时, 接头组织以等轴晶为主, 且气孔等缺陷较少, 此时接头微观闭塞原电池效应微弱, 自腐蚀电流密度最小, 接头耐腐蚀性能相对较好。该研究对深入理解铝合金焊接过程中缺陷形成机理及提高接头耐腐蚀性能是有帮助的。

In order to ensure the enough welding strength and durability of the ship in seawater environment, 5083-O aluminum alloy was used to simulate the corrosion resistance of welded joints in seawater. The effects of laser power, welding current and wire spacing on the corrosion resistance of aluminum alloy welded joints were studied by using the highly adaptable laser-melting inert gas (MIG) shielded welding hybrid welding system. The results show that, the self-corrosion current density increases first, then decreases and then increases with the increase of laser power, and varies in the V-shape with the increase of welding current and wire spacing, that is, it decreases first and then increases. When laser power is 3.0kW, welding current is 200A and wire spacing is 3mm, the microstructures of the joint are mainly equiaxed grains, and the defects such as pores are few. At the same time, the micro-blocking galvanic cell effect of the joint is weak, the self-corrosion current density is minimum, and the corrosion resistance of the joint is relatively good. This study is helpful to understand the defect formation mechanism and improve the corrosion resistance of aluminum alloy welded joints.