Abstract
Friction stir welding (FSW) is a solid-state jointing technology, and has the advantages of high joint strength, low residual stress, and small deformation after welding. During FSW, the welding temperature directly influences the quality of the weldment. A heat generation model of FSW medium thickness aluminum alloy 2219 is established considering the friction heat generated at the interface between the tool and the workpiece and the plastic deformation heat of the weldment material near the tool. The heat transfer model is set considering heat conduction, convection, and radiation. Using JMatPro technology, temperature-related material parameters of aluminum alloy 2219 are obtained. The built heat generation model is imported into the simulation software ABAQUS through the DFLUX subroutine, and the simulation of FSW process is achieved. The effectiveness of the simulation is verified by FSW experiments. The simulation has high prediction accuracy. Based on the simulation, the influence of welding parameters on temperature distribution is explored; subsequently the influence of welding temperature on mechanical properties of welded joint is also studied. The research guides the prediction of the temperature distribution and the improvement of the mechanical performance of FSW medium thickness aluminum alloy 2219.
Highlights
The diameter of a heavy-lift launch vehicle storage tank is up to 10 m, and the thickness of it is up to18 mm
Based on the DFLUX subroutine, the heat generation model is imported in the simulation software ABAQUS, and the Friction stir welding (FSW) thermodynamic model is achieved by combining the heat transfer model, the material parameters of the aluminum alloy 2219, and the friction coefficient
Because of the existence of the tool in the FSW process, the temperature of each position of the weld cannot be obtained; the required temperature is obtained through the FSW thermodynamic model as discussed
Summary
The diameter of a heavy-lift launch vehicle storage tank is up to 10 m, and the thickness of it is up to mm. With the in-depth study of the analytical FSW heat source model, Chang et al [7] established a heat source model considering the frictional heat generation of the tool shoulder, the tool pin, and the weldment, simulated the temperature field of the 4-mm thick 6061-T6 aluminum alloy FSW, and studied the effect of welding speed on the microhardness and tensile strength of welded joints. Analytical FSW heat source models have been studied in great depths, but some FSW heat source models have only considered the frictional heat generation of the tool, while ignoring the heat generated by the plastic deformation of the weldment material during the welding process, which leads to errors in the prediction of the temperature field. It is necessary to establish a FSW heat source model considering friction heat generation and plastic deformation heat generation to explore the temperature distribution of medium thickness aluminum alloy 2219 plate, to ensure the mechanical properties of the FSW medium thickness aluminum alloy 2219
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