Influence of welding methods on the microstructure of nickel-based weld metal for liquid hydrogen tanks

This study investigates the microstructure and hardness of weld metals used in liquid hydrogen storage tanks, with a focus on the effects of three welding methods: Gas Tungsten Arc Welding (GTAW), Submerged Arc Welding (SAW), and Shielded Metal Arc Welding (SMAW). Finite element simulations were employed to model the temperature field during welding, aiding in the explanation of observed microstructural differences. The results show that while GTAW and SMAW produce weld metals with similar microstructures, SAW generates significantly larger grains with a pronounced preferential orientation. The use of weaving techniques play a key role in shaping the solidification microstructures. Additionally, the hardness of the weld metal is comparable to that of the base material, with a slight reduction corresponding to increased grain size. This research offers valuable insights into optimizing welding processes for liquid hydrogen storage tanks by addressing the microstructural characteristics that influence weld joint performance. Graphical Abstract