Development of finite element model to predict temperature and residual stress distribution in gas tungsten arc welded AA 5059 aluminium alloy joints

Abstract

High-strength armour grade AA 5059 aluminium alloy finds wide application in the fabrication of lightweight structures, which require a high strength-to-weight ratio. They include transportable bridge girders and military vehicles. In gas tungsten arc welding (GTAW), fusion zones are characterized by coarse columnar grains due to the thermal condition that prevails during solidification of weld metal. This accounts for inferior weld mechanical properties and poor resistance to hot cracking. The higher temperature and higher thermal gradients in welds make it difficult to exercise control on solidification structure in welds. The modelling procedure was developed in this research work using the software code of COMSOL. The boundary conditions, heat source model and the governing equations were incorporated into the finite element model. It is found that the predicted values of temperature while using three-dimensional finite element model are in good agreement with the experimental values.