Analysis and evaluation of arc stability of self-shielded fluxcored wire in all-position welding

The droplet transfer and arc stability of three kinds of self-shielded flux-cored wires in all-position welding applied in X70 pipeline steel were tested by using high-speed video camera and Hanover Analysator. The results showed that as for all-position welding arc stability, No. 1 wire was the best, No. 3 wire the medium, and No. 2 wire the worst; coefficient of current variability could reflect welding stability more accurately than standard deviation; average short-circuiting time could not be taken as the only way to judge welding arc stability, which should be judged by combining with class frequency distributions diagram of short-circuiting time. During short circuiting transfer, probability density distributions diagram of arc voltage was in double-hump shape, and probability density distributions of double-hump shape curve and convergence of the whole curve could be regarded as important references for evaluating welding arc stability.