Forgings deliver higher strength and toughness then
other methods of producing metal parts. Forgings have higher yield strength, 40% then
cast, machined and welded, (weldments), parts; higher tensile strengths, (over 15%) and
the important quality for an anchor, a much higher percent of reduction of area,
(elongation), of over 50% then casting, weldments, etc. |
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Casting of anchors results in randomly
oriented grain flow while forgings offer a superior more refined grain growth especially
in a selected direction.
Cutting and machining of parts, no matter
how fabricated, suffer from interruption of grain flow resulting in a part that is
susceptible to fatigue and other potential problems including inadequate strength. When
assembling these cut and machined parts into a weldment the dimensional distortion and
HAZ, heat effected zone, effects of like metals results in a product often to
hard with inclusions, brittlement and other defects that will effect an anchors
performance. These problems are exacerbated when using components of different alloys or
metals.
Forgings are rated best in terms of
structural integrity against other fabrications and quality consistence. Inclusions,
macrosegregations, porosity, intergranular corrosion, grain growth, stress crack
corrosion, crevice corrosion and laminations are not problems to forgings but do effect
fatigue and service life of the other forms of fabrications, (i.e.: weldments, castings
and machined parts).
An anchor is required to last the life of
the building without further attention, positioning a worker for the task of cleaning and
maintaining the window and its surrounding area and, if needed, it must arrest any fall of
the worker. Regardless of the environment of the window, this performance is expected
without fear of corrosion or any other problem that may effect the anchors
reliability. |