526 Effect of Tool Shoulder Diameter on Mechanical Properties of Friction Stir Spot Welded Joints

— For fabricating light weight structures, it requires high strength-to weight ratio. AA6061 aluminium alloy is widely used in the fabrication of light weight structures. A356 aluminium alloy has wide spread application in aerospace industries. Friction stir welding is solid state joining process which is conducting for joining similar and dissimilar materials. The friction stir welding parameters play an important role for deciding the strength of welded joints. In this investigation, A356 and AA6061 alloys were friction stir welded by varying triangular, square, hexagonal pin profiles of tool keeping the remaining parameters same and AA6061 alloys were friction stir welded by varying tool shoulder diameter as 12mm,15mm,18mm without changing other parameters. Tensile properties of each joint have been analyzed microscopically. From the experimental results, it is observed that hexagonal pin profiled tool and 15mm shoulder diameter tool provides higher tensile properties when compared to other tools.

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Effect of Rotational Speed and Dwell Time on Mechanical Properties of Dissimilar AA1050-AA3105 Friction Stir Spot Welded Joints*

Materials Testing ◽

10.3139/120.110636 ◽

2014 ◽

Vol 56 (10) ◽

pp. 818-825

Author(s):

Hakan Aydin ◽

Oguz Tuncel ◽

Celalettin Yuce ◽

Mumin Tutar ◽

Nurettin Yavuz ◽

...

Keyword(s):

Mechanical Properties ◽

Welded Joints ◽

Rotational Speed ◽

Dwell Time ◽

Friction Stir ◽

Spot Welded

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Effects of tool shoulder geometry on mechanical properties and microstructure of friction-stir welded joints of AA5083-0 aluminium alloys

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.17.0591 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7507-7519

Author(s):

Francisco Ortega ◽

William Fernandez ◽

Juan Felipe Santa ◽

Jimy Unfried-Silgado

Keyword(s):

Mechanical Properties ◽

Microstructure Evolution ◽

Welding Speed ◽

Welded Joints ◽

Thermal History ◽

Factors Affecting ◽

Friction Stir ◽

Tool Shoulder ◽

History Of ◽

Shoulder Geometry

Shoulder geometry is an important geometrical feature of tool design in friction stir welding since it has a strong effect on heat generation and material flow. In this paper the effect of shoulder geometry of tool on mechanical properties, microstructure evolution, and thermal history of friction stir welded joints of AA5083-O aluminium alloy. Two different shoulder geometries of tool named concave and featured (concentric circles) were used, both with cylindrical threaded pin. A set of samples were fabricated using a milling machine and a factorial experimental design to estimate the effects of process parameters (rotational and welding speed) and shoulder geometry on welded joints. Tensile strength, hardness, and microstructure evolution were experimentally measured. These observations were complemented with results obtained from a finite element modelling to calculate thermal history in welded joints. The results showed that the combination of revolution pitch R-value and shoulder geometry of tool were the most significant factors, affecting to mechanical properties, thermal behaviour, and microstructure evolution. The best tensile properties were obtained with a featured shoulder tool using 1400 rpm and 16 mm.min-1, and 1085 rpm and 11 mm.min-1 for rotational and welding speed. The same parameter combination resulted in a joint efficiency of 70% and 65%, respectively. In addition, the results of evaluation using an ANOVA analysis with fixed factors showed that increasing R-values produces statistically significant differences in ultimate strength (Sut) values.

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