Influence of process parameters on friction stir welded 6082 t6 aluminium alloy of various thicknesses an experimental and numerical investigation

Abstract

Friction stir welding (FSW) is a solid state welding process for newlinejoining metallic alloys. FSW has been employed in several industries such as newlineaerospace and automotive for joining aluminium, magnesium and copper alloys. newlineThe various parameters such as tool rotational speed, welding speed, axial force newlineand attack angle play vital role in the FSW process, in order to analyse the weld newlinequality. The aim of this study is to investigate the effect of tool rotational newlinespeed/spindle speed, welding speed, shoulder penetration, tool pin profile and newlinetool shoulder profile on weld strength at different plate thicknesses of 6082-T6 newlinealuminium alloy. AA6082-T6 finds use for structural and other fabrication newlineindustries. In this work the weld tensile strength was measured and the newlineparameters are optimized by the Taguchiand#146;s orthogonal array. The optimized results show that the larger plate thickness or larger newlinetool diameter requires lower spindle speed and weld speed to obtain the good newlineweld. Larger plate size requires a higher number of sides of the polygon for the newlineeffective stirring process. Similarly the smaller plate size requires less number of newlinesides of the polygon for the effective stirring. The number of sides of the newlinepolygon makes the corresponding pulse per revolution. The results show that newline105 and#150; 110 pulses/sec is the optimum to achieve defect free good weld. The newlinesmaller diameter probe with higher number of striking edges produces finer grains. So the grain size of the 4 mm thickness plate is very small compared with newline6 mm and 8 mm thickness plate. The grain sizes at weld nugget of 4 mm, 6 mm newlineand 8 mm plates are ranging between 3 and#956;m to 4 and#956;m, 4 and#956;m to 6 and#956;m and 5 and#956;m to newline8 and#956;m respectively. Finer grain shows the smaller micro hardness value of 60 Hv. newlineDouble side weld reduces the weld bead to half the size; consequently the newlinethermo-mechanically affected zone and heat affected zone are reduced. This newlineensures near to keyhole weld and also the joint is mechanically sound, which newlineincreases joint efficiency to 5-10%. newline