Effect of Tool Design and Process Parameters on Lap Joints Made by Right Angle Friction Stir Welding (RAFSW)

Mahboubeh Momeni,Michel Guillot

doi:10.3390/jmmp3030066

Mahboubeh Momeni, Michel Guillot

Open Access

https://doi.org/10.3390/jmmp3030066

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Abstract

In recent decades, friction stir welding (FSW) has attracted extensive attention of academic and industrial sectors as the most considerable development in metal joining processes. FSW lap joint is an interesting alternative for rivets, fusion welds and bonding particularly in the transportation industry. In this paper, the effect of tool design and process parameters on the generated downward axial force and strength of AA6061-T6 lap joints is studied. The welds are made by a low-cost friction stir welding technique at right angle (RAFSW). The studied tool design parameters are shoulder diameter, shoulder groove depth, pin length, pin angle, pin base diameter and pin lead. Moreover, the effect of tool rotational speed, traverse speed, plunge depth and lap joint configuration is evaluated. The Taguchi method is used to design the experiments and artificial neural network (ANN) modeling is applied to predict the plunging force and the strength of the joints. The results indicate that a quality weld can be obtained at low downward axial forces during welding by proper selection of tool design and process parameters. It is identified that one can achieve a quality lap joint at traverse speeds as high as 1400 mm/min and downward axial forces as low as 3.2 kN by a low-cost RAFSW technique.

Highlights

Friction stir welding (FSW) is a newly emerged solid-state joining process
The RAFSW technique is capable of making sound, defect-free welds at a zero tilt angle with low axial forces during welding compared to common FSW techniques
There are numerous studies on the effect of tool design and process parameters [7,9] on the quality of the butt joints made by FSW technique, there is less research on the lap joints [8]

Summary

Introduction

Friction stir welding (FSW) is a newly emerged solid-state joining process. In the past decades, it has increasingly attracted the interest of researchers and industry owing to its prominent advantages over fusion welding techniques. There are numerous studies on the effect of tool design and process parameters [7,9] on the quality of the butt joints made by FSW technique, there is less research on the lap joints [8]. Some other research has investigated the impact of the process parameters including the tool plunge depth, rotational speed, traverse speed and configuration of the lap joint on the quality of the welds [11,12,20,21]. There is a lack of information and too few studies on the determination of the effective working window of the tool design parameters and the process parameters to make quality AA6061-T6 lap joints by the FSW technique. High traverse speeds are applied to make the process promising for industrial use

Materials and Methods

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