Investigation of Heat Source Models and Process Factors on Temperature and Residual Stress in GTAW of Aluminum Plates

Abstract

Heat source modeling is one of the most important problems in welding simulation and has a significant impact on temperature and residual stress fields. This paper first investigates accuracy of surface and volumetric heat fluxes for predicting temperature of the gas tungsten arc welding of aluminum plates, through the 3D finite element analysis. Comparing simulated and experimental temperatures shows that the volumetric model produces a more precise prediction of temperature at fusion zone, while temperature at locations far from the weld is independent of the heat source model. Next, this paper investigates the influence of different geometrical, technological, and material variables on the residual stress and the welding temperature, by using the Taguchi method. The results reveal that increase in the yield strength and the plate width lead to a higher residual stress. The yield strength is the most significant parameter, while the heat power and the plate length have insignificant impacts on the residual stress. Further, the order of factors based on their effect on the welding temperature is determined as time, distance, and thickness. The derived equations in this paper can be used to calculate the welding temperature and the residual stress in terms of design factors with high accuracy.