高速列车用铝合金三元气体保护焊技术

研究了氩氦氮三元气体保护焊条件下的铝合金焊接技术,获得了高质量的焊接接头.结果表明,三元气体保护焊电弧收缩显著,溶滴过度稳定,改变铝合金MIG焊的电弧能量密度与温度分布,相对纯氩气体保护焊同等焊接电流下熔深显著增加,熔池流动行为及接头组织改善,冲击韧性和疲劳强度显著提高,阴极清理范围窄,焊缝表面光泽度高,电弧焊焊接操作性好.试验表明三元混合气体保护焊可以提高铝合金焊接质量,具有很高的工程应用价值.

Ternary gas shielded arc welding of aluminum for highspeed vehicles

Arc welding of aluminum was investigated using argon,helium and nitrogen ternary gas,and solid joint with high quality was attained. The experimental results show that with the ternary gas,the arc constricted remarkably,the droplet transferred stably,and the distribution of arc energy density and temperature field was changed during MIG welding of aluminum alloy. In comparison to the MIG welding with pure argon,under the same welding current,the penetration was deeper,the fluid flow in the welding pool and the microstructure of the joint were improved,the impact toughness and fatigue strength of the joint were enhanced. Meanwhile,the cathode cleaning range was narrower, the surface glossiness of the weld was better,and the operation of welding was easier. The experimental results display that the MIG welding with ternary gas could improve the quality of the aluminum weld and is valuable in engineering application.