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.
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 anchor’s 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 anchor’s reliability.