He-Ar混合气体抑制铝合金焊缝皱皮的研究

对大电流MIG焊焊接厚板铝合金时焊缝产生皱皮进行了试验研究与分析,皱皮产生的原因是焊接电弧燃烧不稳定、熔池中的熔融金属发生氧化和氮化反应造成的。研究了100%Ar、75%Ar+25%He、50%Ar+50%He、100%He(体积分数)等4种惰性气体作为内层保护气体,纯Ar为外层保护气在MIG焊接方法时的焊接特性,如焊接电弧的静特性及焊接铝合金材料时对母材的热输入、焊缝的有效熔深等。试验结果表明,不同比例的He-Ar混合气体产生皱皮现象的临界电流值,随着He-Ar混合气体中He气体比例的增大,焊缝产生皱皮的焊接电流值也增大。

Effect of the He-Ar mixture gas on puckering suppression of aluminum alloy welding bead

In this paper,the bead puckering during high current metal-inert-gas shield welding process of thick plate of aluminum alloy is analyzed.The reasons of puckering are due to unsteady arc and oxided and nitrided melt in melt-pool.Furthermore,static characteristic of the arc,welding heat input of the base metal and the effective depth of fusion of the bead in this welding process were prima-rily studied using four kinds of inert gases respectively:100%Ar,75%Ar+25%He,50%Ar+50%He and 100%He as inner shielded gas and pure Ar as outer shielded gas.Then,the critical current values at which puckering appeared on the bead surface were obtained with the above-mentioned four kinds of different gases,and it was found that the current values rise with the ratio of helium in the mixture gas of He-Ar increasing.