Wider Extrusions at Lower Cost by Friction Stir Welding
Kari Erik Lahti, ESAB AB.
Track: VALUE-ADDED PROCESSES
ABSTRACT --- Friction Stir Welding is a solid state welding process that can be used to
join any aluminum alloy, even those that are not arc-weldable. One of its best
applications involves the joining of two or more extrusions to create one wider or more
complex panel. As proof, this technology has successfully been used at two large
extruding companies in Scandinavia for a number of years now.
The mechanical properties of the friction stir welds typically mimic 90 percent of those
inherent to the unwelded parent material. If welded in its T4 condition and aged to T6,
the aluminum’s yield, tensile strength, and elongation characteristics are at the same
level as those of the unwelded parent material.
Weld preparation is simple which further contributes to the cost that the savings
Friction Stir Welding process offers. Only degreasing is considered a pre-weld
requirement to join the two extruded profiles. Due to the low joining temperature heat,
post-weld deformations are not created in the fabricated panels. This alone can result
in savings of up to 20 percent in the final assembly of the end user products.
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