Process Parameters Optimisation for FSW of Al/Stainless Lap Joint

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  • The necessity of reducing fuel consumption and the increasing demands for lightweight vehicles have motivated the use of multi-material combinations. Dissimilar metals have been progressively introduced in different locations to optimize mechanical performance and strength-to-weight ratio. These new combinations of metals need to be joined, which presents a major challenge in conventional fusion welding. Since FSW does not involve bulk melting of the components, it is among the most convenient welding techniques for joining dissimilar materials. In this investigation, process parameters are optimized to produce friction stir lap welds between an aluminum alloy AA5083- H19 and a stainless steel 201LN 1⁄4 hard. For the welding procedure, a WC-25Co welding tool is used. The tool is rotated and penetrated through the aluminum alloy located on the top of the assembly. Key parameters considered to obtain an optimal process window include rotation speed, travel speed, surface and internal defects, lateral force and tool degradation. Microstructural characterization was done by optical and scanning electron microscopy. Tensile lap shear tests were conducted for mechanical property evaluation. Joints produced exhibit good mechanical properties with a tensile shear strength up to 500 N/mm of weld. During the FSW, a significant degradation of the tool was observed due to the combination of high welding temperatures and high material flow stress at the end of the pin tool, where the tool is in contact with the stainless steel. Tool wear was investigated by using 3D digital profilometry scans. Abrasion and adhesion were found to be the most dominant causes of wear.

    Part of the Proceedings of the Canadian Society for Mechanical Engineering International Congress 2022.

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    Attribution-NonCommercial 4.0 International