A novel and efficient underwater magnetically-controlled plasma-FCAW hybrid welding process

To address the issues in conventional underwater welding with a single heat source, such as low welding efficiency, poor weld formation, porosity, and arc instability, an innovative underwater hybrid welding method of plasma-flux cored arc welding (plasma-FCAW) controlled by external magnetic is proposed in this paper. The self-designed hybrid welding torch structure achieves complementary advantages between these two independent welding methods. The external magnetic field design optimizes the arc repulsion issue caused by differing power polarities in the hybrid welding process. This process combines the deep penetration characteristics of plasma arc as well as the high efficiency and high deposition rate of FCAW, while enabling real-time regulation and flexible coupling of the plasma and FCAW arcs through an externally applied auxiliary magnetic field. The results indicate that, compared to traditional underwater FCAW process, the hybrid welding process improves the weld penetration by 30 %, significantly enhancing the stability of the welding process while providing higher welding efficiency. This technology offers a novel approach for the industrial application of underwater welding techniques and holds promise for solving key challenges in underwater welding engineering.