Study on the Optimization of Process Parameters for Submerged Arc Welding of Hydrogen Production Reactor Material

In a hydrogen production reactor based on the principle of coal-to-hydrogen, the welds, which are considered the weak points, must exhibit a good impact resistance property and high hardness under special operating conditions. This paper investigates the influence of submerged arc welding (SAW) process parameters on the hardness and the impact resistance property of welds in the steel used for a hydrogen reactor. It establishes the relationship between the microstructure of the welds and their hardness and impact resistance property under varying welding parameters. Based on orthogonal welding experiments and a comprehensive balance method, the welding parameters were optimized to obtain the best combination of parameters. The results indicate that as the current and voltage increase, the average hardness of the welds first decreases and then increases, while the impact resistance property initially improves before declining. As the welding speed increases, the average hardness of the welds initially increases and then decreases, while the impact resistance property gradually declines. After optimization under specific experimental conditions, the best welding parameters are determined to be a current (I) of 320 A, a voltage (U) of 34 V, and a welding speed (v) of 33 cm/min. Compared to the base metal, the hardness of the weld increased by 36.1%, and the impact resistance property improved by 71.5%.