Prediction of temperature and residual stress distributions in friction stir welding of aluminum alloy

A thermal model considering the heat generated by friction and plastic deformation is developed for friction stir welding. The proportion of heat-generated between friction and plastic deformation depends on the contact states determined by the temperature and velocity of the tool. The model is verified by welding experiment, and the numerical results agree with the experimental data. Then, the effects of process parameters on temperature and residual stress are investigated using the validated model. These process parameters involve the welding speed, rotational speed, and axial force. The results show that the temperature increases with the increase of the rotational speed and axial force, and decreases with the increase of the welding speed. The increase of the axial force and welding speed will lead to larger tensile stress in the weld zone. Furthermore, the relationship between peak temperature, peak residual stress, and process parameters are established though regression method.