Numerical investigation of thermal residual stress distribution for the sustainability of laser welded joints of dissimilar materials

Abstract

In this work, a three-dimensional (3D) time dependent finite element method is used to simulate the thermo-mechanical behavior of laser welded joints. Laser welding of two dissimilar materials (AISI 316L and Ti6Al4V) of 2 mm thickness has been considered while modeling in COMSOL multiphysics with a coupling of heat transfer and solid mechanics module. A total of six temperature dependent physical properties, i.e. density, specific heat, thermal conductivity, coefficient of thermal expansion, Young’s modulus, and Poisson’s ratio have been considered for making the numerical model more realistic. The experimental results show that AISI 316L experiences more than 2 times more maximum stresses than Ti6Al4V near the weld bead region during the process. High value of Von mishes stress in the welded zone can be observed due to high temperature gradients of welds. The simulated value of residual after one entire thermal cycle is near to 80 MPa on a point over weld bead.