Appeal No. 2002-1352
Application 09/051,975
workpiece region due to generated frictional heat, stopping
the relative cyclic movement and allowing the plasticised
material to solidify.
Objectives set forth in the Midling patent are to provide an
improved friction stir welding probe and process which 1) ensures
“high integrity welds free from voids and exhibiting a smooth
surface quality” (col. 1, lines 60-61); 2) provides an improved
method for friction stir butt welding, which method can also be
used for lap welds and for a three or more components joint
configuration; and 3) provides “uniform homogenized weld seams
exhibiting reduced heat affected zone” (col. 1, lines 66-67). At
other points in the Midling patent it is noted that the improved
probe and friction stir welding process therein provides sound
welded joints or seams having a microstructure which is composed
of interlocked plasticised segments of the joined members with
minimal material turbulence (col. 2, lines 48-51) and high
quality welds both with regard to metallurgical and mechanical
properties due to a homogenized weld exhibiting no porosity
through the whole weld cross section (col. 4, lines 7-10).
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