Bar Stool Collapse
Metallurgical examination and
failure analysis was requested of a bar stool
that collapsed while being used in a retail
location. The person seated on the bar stool was
severely injured. An overall view of the failed bar
stool, with one leg missing is shown in Photograph
Failed bar stool with missing
An overall view of the bottom side of the bar stool
is shown in Photograph B. The location of a failed
fillet weld used to connect the bar stool foot ring
to one of the four legs is denoted with a white
Arrow denotes location
of failed fillet weld.
A close-up view of the failed foot ring to leg
fillet weld is shown in Photograph C. Note the
straight edge of the fillet (denoted with arrows)
weld which attached the foot ring to the bar stool
leg. Straight edge of failed weld indicates
lack of weld
penetration into the bar stool leg.
Failed foot ring to leg
Underside (side of weld facing bar stool leg) of
failed fillet weld, shown in Photograph D. Visual
and microscopic examination revealed massive weld
porosity. A close-up view of the area where the
fillet weld was designed to attach the foot ring to
the bar stool leg is shown in Photograph E. White
arrows indicate a heat effect from attempted
welding, but total lack of weld penetration.
Underside of foot ring
to leg fillet weld showing weld porosity.
Bar stool leg showing
lack of weld penetration.
For reference purposes, a properly and adequately
welded leg to foot ring joint is shown in photograph
Properly welded leg to
foot ring joint.
The failure of the subject bar stool was the result
of lack of welding (weld penetration) between the
bar stool ring and the bar stool leg. Massive weld
porosity was a symptom of defective, improper and
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