Thermal modeling of friction stir welding of stainless steel 304L

This paper presents a numerical model, based on the displacement of one point of the material flow relative to a fixed reference point, in order to formulate the heat generation during friction stir process and thereby calculate the temperature difference between advancing and retreating sides. This model considers frictional heating dependent on both the temperature and the velocity of the tool, as well as heat generation due to plastic deformation dependent on temperature, and assumes that friction heat at high temperature was replaced by heat generation due to plastic deformation. The heat generated by plastic strain energy dissipation in thermomechanically affected zone is calculated by a new technique, and the convection heat transfer coefficient and the sticking state parameter are considered as a function of temperature. Finally, the thermal equations are solved using a nonlinear finite element code ABAQUS. The numerical results correctly showed the asymmetric nature of temperature distributed at different sides of the weld line which have good agreement with experimental data that are presented in the literature.