OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
EFFECT OF TOOL SHAPE ON TENSILE STRENGTH IN SINGLE AND
SEQUENTIAL DOUBLE SIDED FRICTION STIR WELD ON AA1100
ALUMINUM ALLOY
Vinod Kumar 1 , Kamal Jangra 2 and Vikas Kumar 3
1 Research Scholar. Department of Mechanical Engineering, YMCA UST, Faridabad, India, 121006
2 Assistant Professor, Department of Mechanical Engineering, YMCA UST, Faridabad, India, 121006
3 Associate Professor, Department of Mechanical Engineering, YMCA UST, Faridabad, India, 121006
Abstract
In present work, an investigation has been carried out on friction stir welding (FSW) on AA1100 aluminium
alloy using high carbon high chromium alloy steel tool. Four types of tool pin profiles namely straight
cylindrical, threaded, triangular and square were investigated. Tool rotation and traverse speeds were kept
constant at 1200 rpm and 20mm/min while shape of the tool and number of passes were two variables. Results
show that maximum tensile strength occurs across the weld zone as compared to the parent material. Threaded
tool pin profile exhibited superior tensile properties compared to other joints, irrespective of tool rotational
speed in double pass. The joints fabricated by single pass have shown lower tensile strength and also percentage
of elongation compared to the joints fabricated by double pass and this trend is common for all the tool profiles.
Keywords: Friction Stir Welding, Aluminium Alloy AA1100, Tensile strength.
1. Introduction
AA1100 aluminium alloy (Al–Mg–Si alloy) has been most widely used in the fabrication of light weight
structures because of requirement of a high strength-to-weight ratio and good corrosion resistance. Compared to
the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding
(FSW) process is an emerging solid state joining process in which the material that is being welded does not melt
and recast. Friction stir welding (FSW) is a relatively new solid state welding process which is used for butt
joints. FSW was invented by the Welding Institute, Cambridge, UK in 1991 and has emerged as a new process
for welding of aluminium alloys (Thomas et al. 1991). This process has made possible to weld a number of
aluminium alloys that were previously not recommended (2000 series & copper containing 7000 series
aluminium alloys) for welding. Because the material subjected to FSW does not melt and re-solidify, the
resultant weld metal is free of porosity with lower distortion. An added advantage is that it is an environmentally
friendly process. FSW is a solid state, localized thermo mechanical, joining process.
Figure 1 Schematic representation of FSW (Balasubramanian et. al. 2008)
Figure 1 shows the schematic representation of FSW. In FSW, a non-consumable rotating shouldered-pin-tool is
plunged into the interface between two plates being welded, until the shoulder touches the surface of the base
material, and then tool is transverse along the weld line. In FSW, frictional heat is generated by rubbing of tool
shoulder and base material surface. During traversing, softened material from the leading edge moves to the
trailing edge due to the tool rotation and the transverse movement of the tool, and this transferred material is
consolidated in the trailing edge of the tool by the application of an axial force (Ma ZY, 2008). The length of tool
profile pin is slightly less than thickness of the work piece thickness plate and diameter of tool pin profile is
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