Papers by Author: Ha Geun Kim

Abstract: The purpose of this study is to identify the principal factors controlling the formability of TMCP steel for curved hull plate. In order to do it, the initial residual stress in TMCP steel was evaluated using flatness measured in the flat bar cut by flame and analytical approach. Changes of the curved profiles in conventional steel and EH 36 TMCP steel of 50mm thick during cold bending and local heating were investigated using 3 dimensional measuring instruments. It was found that the formability in TMCP steel was mainly determined by the excessive distortion by the relaxation of residual stress during cold bending.

Abstract: The purpose of this study is to establish the proper control method of angular distortion of multi-pass STS 316LN weldment in the vacuum and cryostat vessel of the fusion reactor. To achieve it, the predictive equation of angular distortion in the multi-pass STS 316LN weldment with reference to welding heat input and effective bending rigidity of weldment was established using FEA and experiment. The bending restraint degree of each weldment in the the vacuum vessels of the fusion reactor was evaluated using FEA. Based on the prediction equation of distortion, both proper welding deposit sequence of double sided butt weldment of STS 316LN for cryostat vessel and proper welding sequence for the vacuum vessel were established and verified by the measured distortion of actual welded structure.