Multiphysics Study of Thermal Profiles and Residual Stress in Welding

Abstract

One of the effects of welding is residual stress. Welding involves complex tests concerning differences in values of the mechanical parameters of its regions as an effect of residual stress. Such multiphysics characteristics of welding pose a challenge in predicting residual stress. In the present study, a thermo-mechanical constitutive model considering phase transformation and transformation plasticity is implemented in the numerical model in ABAQUS user subroutines. In order to consider phase evolution in welding, the metallurgical parameters for Leblond’s phase equation were obtained from the calibration of DH36 steel with a CCT diagram. In addition, the effects of welding speed on thermal profiles and residual stress generation were investigated. Analysis has suggested that the width of the heat-affected zone (HAZ) decreases with an increase in welding speed, and the phase fraction is significantly affected by this kind of parameter. Such phase transformation has led to the generation of a compressive stress in the fusion zone (FZ) and HAZ. The volume difference between coexisting phases produces a compressive stress in cooling, and its magnitude was increased with martensite increasing.

Numerical Simulation of Temperature Evolution, Solid Phase Transformation, and Residual Stress Distribution during Multi-Pass Welding Process of EH36 Marine Steel

“…Given these constraints, there is an urgent need for reliable numerical methods to estimate the distribution of residual stress. In comparison to experiments, numerical simulation offers the advantages of high efficiency and costeffectiveness [13][14][15][16][17]. This is particularly applicable to the high-heat-input welding, where the measurement of temperature and stress distribution within both the molten pool and heat-affected zone presents great difficulties [16][17][18][19][20].…”