SPATTER AND FUME REDUCTION IN CO2 GAS-SHIELDED ARC WELDING BY REGULATED GLOBULAR TRANSFER

The CO2 gas-shielded arc welding process with solid wire is widely used in Japan due to its good weld quality, high efficiency and reasonable wire and shielding gas costs. However, this process has its drawbacks, especially in the globular transfer mode at a high welding current, where significant amounts of spatter and fume are generated. To solve this problem, the author has investigated how to control globular transfer with a special pulsed current and has developed a regulated method and power source for practical use. The present report discusses the mechanism of this new method of regulating the globular transfer of molten droplets, in which each droplet is squeezed at its upper part in peak current duration and is detached silently in base current duration. Also various effects are reported concerning this new method and its application in the welding robot system for fabricating steel frames for buildings.