Thermal stress history in high-tensile strength steels during weld process

Abstract
Thermal and residual stresses in High-Tensile Strength Steels during weld process are numerically simulated considering phase transformation effect. Fundamental study for the history of thermal stress due to phase transformation and residual stress during welding heat cycles is studied in order to investigate the generating mechanism of residual stress and the effects of material properties on stress generation. Two materials of high-tensile strength steels are used in the numerical simulation and experiment. Material property of each microstructural phase is used and the time- and temperature-dependant proportion of microstructure are considered by using CCT-diagram in the analysis. Thermal stress history obtained by the simulation agrees well with the experimental result during welding heat cycles. Some applications to repair welds and fillet-weld joints of the analytical method are then introduced.