Continuous contact transfer behavior in bypass coupling triple-wire indirect arc welding

Abstract

Continuous contact transfer mode in bypass coupling triple-wire indirect arc welding (BCTW-GIA) is proposed to pursue an optional way to ensure the high deposition rate and obtain stable depositing process. The arc behaviors, droplet transfer and process stability with different distance between the tips (d1) of the main wire and side wires and the feeding speed of main wire (FSM) were studied. With the increase d1 and FSM, the droplet transfer mode of main wire varied from explosive transfer to short-circuit transfer to bridge transfer. When the d1 was greater than 4 mm, the continuous contact transfer bypass coupling triple-wire indirect arc welding can be realized and the welding process stability was improved. With the d1 adjusted from 0 mm to 6 mm, the standard deviation of the current dropped from 123.8 to 53.8 and its variation coefficient from 117.33–39.24% at FSM = 1 m/min. The weld penetration and weld width reduced with the FSM increasing, while the weld reinforcement gradually increased.