Effect of Multi-facets Stirring Pin on Material Flow Behavior for Friction Stir Welding

doi:10.3901/JME.2022.06.081

Abstract

Abstract: Compared with conventional fusion welding, Friction stir welding (FSW) is a very promising method for solid phase welding of aluminum alloys due to its low temperature gradient, which can reduce welding cracks and residual deformation. Under the same welding parameters, the stirring pin is one of the main factors affecting the welding heat input and material flow, which determines the microstructure and properties of welding seams. Based on solid mechanics finite element method (FEM) and A7N01 aluminum alloy material constitutive equation, this study simulated friction stir welding of an A7N01 weld using the Deform software. The rigid visco-plastic simulation model was verified by comparing with measured temperatures and observed defects in welding tests. Three kinds of stirring pins, namely cone, three-plane and four-plane, were designed. The model was then used to investigate the influence of three kinds of stirring pins on the temperature field, peak temperature curve and material flow behavior in the steady-state welding stage of friction stir welding. The results showed that the welding heat input of the multi-facets stirring pins (3P & 4P) was higher than that of the cone stirring pin (Y), and it was better than that of the cone stirring pin in terms of plastic flow range, flow uniformity and effective weld. The flow materials was strongly extruded by the sitrring pin facets, so as to refine the grain in the weld zone and improve the mechanical properties of the welded joint. Based on the simulation and test results, the causes of the welding furrow defects were revealed, and the preventive measures were put forward.

Key words: friction stir welding, multi-facets stirring pin, plastic flow of material, welding heat input

CLC Number:

TG156

Yang Zhiyong, LI Wupeng, LI Zhiqiang, Liu Xiaolong, LI Weijing. Effect of Multi-facets Stirring Pin on Material Flow Behavior for Friction Stir Welding[J]. Journal of Mechanical Engineering, 2022, 58(6): 81-90.

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