The International Maritime Organization (IMO) is promoting the transition to eco-friendly fuels such as hydrogen and ammonia, with the goal of achieving net-zero greenhouse gas emissions in the shipping sector by 2050. Hydrogen does not emit greenhouse gases, but it must be stored at an extremely low temperature of -253°C when stored as a liquid. 316L stainless steel is mainly used as a tank material to store liquid hydrogen. FCAW (Flux Cored Arc Welding) is known for its excellent weldability with 316L stainless steel, and it is particularly suited for welding thick metals efficiently, making it an ideal choice for storage tank welding. Finite Element Method (FEM) analysis can simulate the thermal and mechanical deformations occurring during welding with high precision, allowing for accurate prediction of deformation patterns and the derivation of optimal welding conditions. This ensures the stability and quality of the structure while reducing costs. In this study, FCAW butt welding was performed on 316L stainless steel, followed by cross-sectional observation and deformation measurement of the weld area. Based on the cross-sectional observation, a 3D FE model was designed, and heat transfer analysis was conducted. Subsequently, thermo-mechanical analysis was carried out to predict welding deformation.

LNG makes cryogenic conditions, so metals without low-temperature brittleness must be used. The International Maritime Organization (IMO) defines 9% Nickel steel, STS304L, 36% Nickel steel and Al5083 as metals that can be used in cryogenic conditions through the IGC Code. In this study, Al5083-O was studied to minimize welding distortion, and verified through finite element analysis and experiments. The block dumping method, which is advantageous in terms of analysis time and cost, was used, not the continuous heat source method. The constraint models with the thickness direction and the tensile force model were compared with the reference model, it was confirmed that the tensile force model had no significant effect. After verifying through the experiment, it was confirmed that the trend of the finite element analysis model was consistent with the experiment. Through this study, a welding distortion minimization model could be found with the block dumping method. It is judged that simulation of many models through short time analysis will be of great help in the field.