焊丝直径和保护气体对GMAW熔滴过渡形态的影响

综述了焊丝直径和保护气体对GMAW熔滴过渡影响的新发现。研究表明,对于直径小于0.90 mm焊丝,转变电流后熔滴的平均直径并未小于原来的焊丝直径。随着焊丝直径的减小,临界电流呈减小趋势,但超细焊丝未测出这种趋势。直径小于0.90 mm的焊丝,增大电流不发生转变,是因为焊丝直径不能明显改变阳极斑点面积,电弧无法爬上熔滴。CO_2对较细焊丝熔滴过渡转变的影响,并未遵循随着CO_2含量的增大,转变电流提高的一般焊丝的模式。无论焊丝直径如何,用含30﹪以上的CO_2保护气体时,排斥过渡仍占主导地位。

Effect of electrode diameters and shielding gases on droplet transfer form in GMAW

In this paper,a new discovery of the influence of electrode diameter and shielding gas on the GMAW droplet transfer was reviewed.The results show that the average droplet diameters do not become smaller than the electrode diameters after the transition current,for the electrode with less than 0.90 mm diameter.As the electrode diameter decreases,the critical current shows a decreasing trend,but the trend of this kind of change is not detected in the superfine electrode.For with diameter less than 0.90 mm,transition does not occur when the current increases,because the electrode diameter can not change the anode spot area obviously,arc can not climb up the molten droplets.The effect of CO2 on the transition of the droplet transfer in the fine electrode does not follow the normal electrode transfer mode that the transition current is increased as the CO2 content increases.Repelled transfer is dominant with shielding gas compositions containing more than 30％ CO2 regardless of electrode diameter.