A Analysis the influence of threaded pin profiles in friction stir welding by numerical simulation

Currently, the welding industry has made significant contributions in most production fields to meet the needs of people's lives. However, traditional welding methods have disadvantages such as: a large amount of energy consumption, production of many toxic gases that are harmful to the environment and the health of workers. Therefore, the friction stir welding method was introduced from the research of scientists to overcome the above disadvantages. Besides that, it is suitable for welding aluminum alloys and non-ferrous metals with low melting point. This green welding technology has been continuously researched to improve weld quality through two main research models: experiment models and numerical simulation models. Experimental results provide provides the basic mechanical properties of the materials at the weld and the process optimization parameters. It will be the basis to establish a numerical simulation model closest to reality, based on mathematical models and working principles, thereby helping to predict weld quality through prediction of formation defects, temperature distribution with changes in welding process parameters such as time, velocity, material or welding pin profile. In this study, the influence of threaded pin profiles on weld quality of alloy aluminum 7075 -T6 during friction stir welding was investigated by numerical simulation model through ABAQUS software to recommend a new pin profile bringing an efficient welding process. To increase the reliability of this research approach, the numerical simulation results of the temperature distribution are compared with the experimental results obtained from a foreign scientific paper with an average error of 14%. Threaded pin profiles are designed in combination with three cross-sections having different opening angles named TF0, TF30, TF60 and TF90. Coupled Eulerian-Lagrangian formulation is applied for this model where the welding tool is Lagrangian domain and workpiece is Eulerian domain. Because material deformation in friction stir welding process is large and related to temperature, the elastic-plastic Johnson-Cook model is used for workpiece. Results of this research shows a new pin profile named TF60 which it gives the best weld quality of the four configurations of the pin tool examined in this study through evaluating temperature distribution and predicting weld defect formation.