A novel strategy for metal transfer controlling in underwater wet welding using ultrasonic-assisted method

In this work, a new lateral ultrasonic-assisted droplet transfer controlling method was innovatively developed in the underwater wet welding process. The ultrasonic acoustic streaming can overcome the resistance caused by arc bubble rising, promote the metal transfer and reduce the proportion of droplet repelled spatter from 9% to 5%. The proportion of unstable droplet transfer mode decreased from 64% to 41%, which obtain a welded joint that was smooth and free of defects. The proportion of pro-eutectoid ferrite was decreased while the weld metal presented a finer microstructure. As a feasible and high-efficiency method, it is expected to spread the application of underwater wet welding in ocean and coastal engineering. (C) 2020 Elsevier B.V. All rights reserved.