Asymmetry Thermal Analyses of Self-Supporting Friction Stir Welding

Zenglou Li,Chong Li,Zhenguo Qi,Yalin Tian,Shuohan Li,Demeng Yin

doi:10.3389/fmats.2021.813661

Abstract

Due to the inherent issue of requiring rigid back support, friction stir welding (FSW) has serious limitations for the welding of hollow structures. Self-supporting friction stir welding was proposed to join hollow aluminum extrusions, which could reduce the hindrance of the welding tool and the requirement of rigid back support. In this paper, finite element modeling analyses were carried out for the asymmetric temperature field in the process of self-supporting FSW. The peak temperature of the stir zone appeared in the upper shoulder affected zone, followed by the lower shoulder affected zone. In the upper shoulder affected zone, a peak temperature was not shown at the center of the curve due to the positive correlation between heat generation and radius and different heat dissipation rates. Considering the influence of thermal input and rotation speed on joint formation, 200 mm/min travel speed and 800 rpm rotation speed are the most proper parameters for 5-mm-thick 6082-T6 aluminum alloy self-supporting FSW butt welds.

Highlights

Sparked with its solid-state joining and excellent strength efficiency, friction stir welding (FSW) has become a novel solid-state welding technology (Huang et al, 2018a; Meng et al, 2021)
The peak temperature of the stir zone appeared in the upper shoulder affected zone, followed by the lower shoulder affected zone
The peak temperature and the hightemperature residence are reduced with the increase of travel speed

Summary

INTRODUCTION

Sparked with its solid-state joining and excellent strength efficiency, friction stir welding (FSW) has become a novel solid-state welding technology (Huang et al, 2018a; Meng et al, 2021). The frame parts of high-speed railway vehicles mostly adopt hollow or enclosed profile structures (Trueba et al, 2018), which is an important application of FSW technology in the manufacturing of railway vehicles (Xu et al, 2018; Yang et al, 2018) It has certain limitations in the engineering manufacturing process due to the inherent issues of the conventional FSW method (Huang et al, 2013; Xie et al, 2020): 1) A rigid back support is required to prevent the weld from collapsing, which is difficult for the hollow or enclosed profiles to provide; 2) The welding adaptability of non-linear welds is poor. The optimized welding parameters were obtained from the simulation results, which was helpful to improve the process design of SSFSW and improve the joint quality

MODELING METHODOLOGY

AND DISCUSSION

CONCLUSION

Findings

DATA AVAILABILITY STATEMENT