Effect of Arc Welding and Friction Stir Welding Processes on Sidewall Welding Deformation of Aluminum Alloy Carbody in High-speed Railway EMU

Abstract

［Objective］ Due to the influence of thermal conductivity and linear expansion characteristics of aluminum alloy materials, welding deformation is prone to occur during the welding process of aluminum alloy carbodies in high-speed railway EMU (electric multiple units). It is necessary to study the currently mature arc welding process and the next-generation friction stir welding process, so as to compare and analyze the welding deformations caused by these two methods. ［Method］ The experimental materials and methods are introduced, and three parameters of curvature, height, and deflection for carbody sidewalls are selected as indicators for comparing welding deformation. Based on results from reverse-assembly welding and forward-assembly welding experiments, the curvature, height, and deflection deformation values of carbody sidewalls are compared in terms of the arc welding and friction stir welding processes. The welding deformation changing trends under the two processes are analyzed. ［Result & Conclusion］ The aluminum alloy carbody sidewalls manufactured using friction stir welding process can effectively reduce welding deformation. The post-weld curvature deformation of friction stir welding is 20% of that of arc welding. Friction stir welding will not cause shrinkage deformation of sidewall profiles in the height direction. However, compared with arc welding, the deflection rebound of the sidewalls after welding is greater with friction stir welding.

Keywords

• high-speed railway
• emu
• aluminum alloy carbody sidewall
• welding deformation
• friction stir welding process
• arc welding process