The influence of pressure environment on the welding process and weld performance of automatic flat SMAW

In order to explore the feasibility of underwater local-dry shielded metal arc welding（SMAW） for groove welding in the water environments（＜40m） and to investigate reasonable welding process, automatic welding experiments in a pressure chamber, using a self-developed automatic SMAW mechanism, were conducted to simulate the welding process under water depths of 20m and 40m. The experimental results showed that the arc stability at a simulated-environment pressure of 0.2MPa was better than that at the atmospheric pressure, while the arc length varied more frequently and the stability decreased at a pressure of 0.4MPa. By analyzing the experimental results of the welding process, welding parameters that produced well-formed welds under both pressures were obtained. Mechanical performance tests confirmed that using these welding parameters for multi-layer multi-pass groove welding can produce weld joints with excellent performance.