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
The welded specimens were put under tensile testing and the values of ultimate tensile strength, percentage
elongation and joint efficiency were noted. The ultimate tensile strength and percentage of elongation of base
metal are 117.33 N/mm 2 and 14.6%. The results of tensile loading of the welded specimens in single and double
pass are shown in Table 1 and 2 respectively. Transverse tensile properties of FSW joints i.e. ultimate tensile
strength, percentage elongation and joint efficiency were evaluated as shown in Figures 3-5 respectively.
Variation of Joint Efficiency
115
110
Joint Efficiency
105
100
95
90
Single Pass
Double Pass
85
SC SQ TH TR
Tool Profile
Figure 5 Variation of Joint Efficiency
From Figures 3-5, it can be seen that the tool profile and passing of tool in full depth are influencing parameters
on tensile properties of the FSW joints. In single pass, the highest tensile strength of the joints was obtained by
using the triangular pin profile tool. The triangular pin profiles tool is best and tensile strength significantly
decreases for threaded, square and cylindrical pin profile tool due to defect formation. The welding parameters
have similar effects on the tensile properties for straight cylindrical and square pin profiles tools.
Threaded tool pin profile tool exhibited superior tensile properties compared to other joints, irrespective of tool
rotational speed in double pass. Similarly, the joints fabricated by triangular pin profiled tool are also showing
almost matching tensile properties to that of threaded tool profile. The joints fabricated by single pass have
shown lower tensile strength and percentage of elongation compared to the joints fabricated by double pass and
this trend is common for all the tool profiles. This is because of uniform distribution of the finer Si particles,
grain refinement of aluminium matrix. From the analysis of fractured surface it can be inferred that the defect
free welds are showing uniform deformation across the weld before failure. Welded specimens failed in region
corresponding to the outer HAZ.
The maximum and minimum ultimate tensile strength in using single pass was 126.9N/mm 2 and 112 respectively
while maximum and minimum ultimate tensile strength in double pass was 133.3 N/mm 2 and 118.4 respectively.
4. Conclusion
In this investigation an attempt has been made to study the effect of tool pin profile (straight cylindrical,
threaded, triangular and square) on tensile strength in single and sequential double sided friction stir welding of
AA1100, aluminium alloy. Welded specimens were failed in region corresponding to the outer heat affected zone
(HAZ). The joints fabricated by double passes have shown higher ultimate tensile strength and percentage
elongation as compared to the joints fabricated by single pass and this trend is common for all the tool profiles.
References
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process parameters”. Materials Science and Engineering Journal 480, pp 397–403.
Cavaliere P. , Santis A.De, Panella F., Squillace A. (2009), “Effect of welding parameters on mechanical and
micro structural properties of dissimilar AA6082–AA2024 joints produced by friction stir welding”. Materials
and Design Journal 30, pp 609–616.
Cabibbo M., McQueenb H.J., E. Evangelista E., Spigarelli S., Paola M. Di, Falchero A. (2007), “Microstructure
and mechanical property studies of AA6056 friction stir welded plate”. Materials Science and Engineering
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Cui Ling, Fujii Hidetoshi, Tsujib Nobuhiro and Nogi Kiyoshi (2007), “Friction stir welding of a high carbon
steel” .Scripta Materialia 56, pp 637–640.
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