Minimization of Welding Distortion in Large-Scale Welded Structures Using the MAG Method: Numerical and Physical Simulation of the Welding Process

This paper presents the results of research on minimizing welding distortion in a large-scale storage tank bottom made of S235JR steel with a diameter of 10,000 mm. The welding technology previously employed guaranteed flatness tolerances of the bottom plates in accordance with the EN 14015 standard at a ratio of T = 0.25% × D = 25 mm, where D represents the diameter of the tank bottom. The objective of this study was to investigate the possibility of reducing this value to the target level of ΔT = 0.2% × D = 20 mm. Two clamping system configurations, used to restrain the tank bottom plates during welding, were analyzed. Numerical simulations of both configurations were performed using the finite element method (FEM) in the SYSWELD software. For the selected clamping configuration, a physical simulation of the welding process was carried out, followed by an analysis of the distribution of welding-induced distortions in the storage tank bottom with respect to compliance with the required bottom plate flatness tolerance of 0.2% × D.