Numerical Simulation of Temperature Field and Material Flow in Friction Stir Welding

In order to study the temperature field (TF) distribution and material flow (MF) in the friction stir welding process, the finite element model of friction stir welding (FSW) was established to simulate the welding process. The temperature field results showed that the temperature on the advancing side (AS) was higher than the retreating side (RS). The temperature field has an important influence on the material flow, so the material flow in the plunging stage and welding stage is simulated numerically to study the material flow trajectory in different stages. The results show that the material distribution is more uniform due to the long time in the plunging stage, and the amount of material flow in the plunging stage is larger than that in the welding stage. In the welding stage, it is found that the shoulder can promote the material flow. After analyzing the displacement of tracking particles in the welding stage, it is found that the displacement of particles on the AS is significantly higher than that on the axis and the RS. Introduction Friction stir welding (FSW) is a solid phase joining technology. Because of its good weld performance and green pollution, it is widely used in the welding of light alloys in the aerospace and other industries [1-3]. However, if the welding parameters are not controlled properly in the welding process, abnormal material flow (MF) will lead to the formation of weld defects [4,5]. FSW process is a complex process of thermal-mechanical coupling, and the temperature field (TF) as the heat source input in the welding process is very important for the realization of FSW process. Some scholars have conducted some research on this process [6-9], but the simulation of temperature difference between the AS and the RS is relatively rare. The MF field has an important influence on the quality of weld forming, so it is necessary to study the MF, which is helpful to understand the process of FSW and explore the rule of weld forming [10]. In this paper, the finite element model of FSW is established to simulate the welding process, and the temperature field of the FSW process is studied. The temperature field of the welding zone has an important influence on the MF. Therefore, the numerical simulation of the MF in the plunging stage and the welding stage is carried out to study the influence of the tool on the MF trajectory. Finite Element Model The FSW process is a dynamic nonlinear process. The welding process is numerically simulated based on the Lagrange method. The tool material is W6, and the workpiece size is 150mm×100mm×6mm for the 2A14-T6 aluminum alloy. The tool shoulder diameter is 16.3mm, the tool cone angle is 15°, and the tool pin length is 5.7mm. In order to improve the accuracy of simulation solution, the workpiece and the tool are refined by adding meshwindow. the refined result is shown in Figure 1. The absolute mesh size is used to control the solution accuracy, but this method will increase the solution time to some extent. The software uses mesh adaptive techniques to prevent mesh distortion International Conference on Modeling, Analysis, Simulation Technologies and Applications (MASTA 2019) Copyright © 2019, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Intelligent Systems Research, volume 168