عنوان المقالة: Effects of Rotational Speeds and Tool Pin Geometry on Microstructure and Mechanical Properties of Refilled Friction Stir Spot Welds of Similar AA2024-T3 Aluminum Alloy Sheets
Dr. Muhammed Abdul Sattar Muhammed ,, Haidar Kamal Ibrahim ,, Asst. Prof. Dr. Abdul Wahab Hassan Khuder
Abstract
Abstract-Friction stir spot welding (FSSW) is a type of solid
state joining processes, which was derived from the linear
friction stir welding (FSW) as an alternative method for
single-point joining processes like resistance spot welding and
fastening. The main limitation of FSSW is the keyhole that
remains at the center of the spot after welding process, which
can be classified as a defect for the friction stir spot welding in
its conventional method. In this work, a newly developed
technique called friction stir spot welding with refilling by
friction forming process (FSSW-FFP) was used to remove the
keyhole from the conventional FSSW joints. Both of this new
technique and conventional friction stir spot welding process
were used to weld lap shear specimens of AA2024-T3
aluminum alloy sheets, thickness 2 mm, and the results were
compared. Two types of tool pin geometry (straight
cylindrical & triangular) and three rotational speeds (535,
980, and 1325) rpm were used to study the effect of these
parameters on the mechanical and microstructural properties
of friction stir spot welds. The keyhole was successfully
refilled by the new refilling process. The tensile-shear test
results showed that the refilled FSSW specimens are better
than the specimens welded by the conventional FSSW process
at all tool rotational speeds with using different tool pin
profiles. The minimum tensile shear load obtained from the
conventional friction stir spot welds was improved (to about
45%) by the refill FSSW process. Fracture modes under
tensile shear tests were analyzed in detail using the scanning
electron microscope (SEM). The variation of microhardness
in different regions of the spot was evaluated.
Publication Date
4/20/2017
Publisher
International Journal of Engineering Research & Technology (IJERT)
د.عبدالوهاب حسن خضر | Dr. Abdulwahab Hassan Khuder | 3831