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Home >> Information >> Hardware Terms - hardware terminology-L&R

Hardware Terms - hardware terminology-L&R

Date: 6/4/2008 6:09:49 AM

Hardware Terms--hardware terminology


 

This is a list for all the abbreviations and terms used when looking at our hardware. If you still don;t understand something, don't hesitate to give us a call.

AN
Stands for Air Force-Navy.
ANSI
Stands for American National Standards Institute.
ASME
Stands for American Society of Mechanical Engineers.
ASTM
Stands for American Society of Testing and Materials.
ANNEAL
To heat metal in order to lower its hardness. The term anneal refers to the heat treatment given to 300 series stainless and most 400 series stainless by the steel mill after the raw material has been completed, but before fittings are manufactured. Anneal also refers to the heat treatment given 400 series stainless fittings after their manufacture (also called hardening and tempering) to lower hardness and increase toughness. For example, fittings of 410 stainless may score over 200,000 psi after manufacture and be too brittle. By annealing at 1000 degrees F., tensile strength would reduce to 125,000-150,000 psi, while annealing the same material to 500 degrees F. would bring tensile to 160,000190,000 psi.
BL
Stands for "Break Load", meaning the weight at which a product will break. Typically, Suncor products have a minimum 4:1 safety factor. "17-4 PH" a chromium-nickel grade of stainless steel that has excellent mechanical properties at a high strength and hardness level. Scaling and distortion are minimal. Both the strength and corrosion resistance hold up well in temperatures to 800°F, but material is magnetic. "18-8" 300 series stainless steel having approximately (not exactly) 18% chromium and 8% nickel. The term "18-8" is used interchangeably to characterize fittings made of 302, 302HQ, 303, 304, 305, 384, XM7, and other variables of these grades with close chemical compositions. There is little overall difference in corrosion resistance among the "18-8" types, but slight differences in chemical composition do make certain grades more resistant than others against particular chemicals or atmospheres. "18-8" has superior corrosion resistance to 400 series stainless, is generally nonmagnetic, and is hardenable only by cold working.
ELECTROPOLISHING
Electropolishing is primarily used to obtain a bright, clean appealing surface. However it also passivates the surface while removing burrs, sharp edges, microscopic nicks and scratches from the surface. It can smooth threads and remove heat discoloration from spot or TIG welds. Suncor products are electropolished to ASTM Standard A967.
ELONGATION
Stretching a fitting to the point that it breaks. The percent of elongation at rupture (same as measure of ductility) is determined by dividing to total length after stretching to the original length. Elongation decreases as strength and hardness increase.
GALVANIC CORROSION
An accelerated degree of corrosion occurring when two different metals are in contact with moisture, particularly sea water. All metals have what is termed a specific electric potential, so that low level electric current flows from one metal to another. A metal with a higher position in the galvanic series (see below) will corrode sacrificially rather than one with a lower position, meaning stainless, for example, will corrode before gold. The further apart the metals on the chart, the more electric current will flow and the more corrosion will occur. No serious galvanic action will occur by combining the same metals, only dissimilar ones. To prevent galvanic corrosion, use insulation, paint or coatings when separating dissimilar metals; or put the metal to be protected next to a metal which is not important in the assembly, so it can corrode sacrificially. Metals listed first will corrode due to galvanic reaction before those at end of paragraph: Magnesium, zinc, aluminum 1100, cadmium, aluminum 2024, steel and iron, lead, tin, brass, copper, bronze, monel, 304 and 316 stainless (passive), silver, titanium, graphite, gold.
ISO
Stands for International Organization for Standardization.
MS
Stands for Military Standards. The overriding characteristic of MS fittings compared to commercial products is the extensive inspection and lot traceability for MS, guaranteeing the chemical, physical and dimensional qualities. While commercial fittings may look similar and happen to pass many tests given MS products, the commercial fittings lack the pedigree of guaranteed quality or chemical, physical and dimensional aspects that users who order MS fittings rely on.
MAGNETIC PERMEABILITY
Test simply determines the level of magnetism. Virtually all Suncor products have a value less than 2.5.
MOLYBDENUM
Molybdenum is a metal added to 316 stainless steel, sharply increasing its corrosion resistance to chlorides and sulfates especially various sulfurous acids in the pulp industry. Molybdenum helps reduce hardness and increase tensile strength at higher temperatures.
MONEL
Invented by the International Nickel Co., and composed basically to two-thirds nickel, one-third copper. Monel has good strength, excellent corrosion resistance against salt water and in high temperatures, but is very expensive.
NITRONIC 50
(UNS S20910) Invented by the Armco Steel Company, Nitronic 50 is a chromium-nickel-manganese-molybdenum austenitic stainless steel. It remains completely non-magnetic after severe cold working or exposure to low temperatures. Sought after for its higher strength and greater corrosion resistance.
NM
Stands for non-magnetic. Varying standards of magnetic units are applied to different metals for this designation.
PASSIVATING
Technically, passivation is not cleaning but is a process of dipping fittings into an acid solution to rapidly form a chromium oxide on the surface of the material, creating a passive film that protects stainless from further oxidation (see PASSIVE FILM). In common commercial terms (meaning non-military and aerospace), passivating means cleaning to users, and the terms "passivating" and "cleaning" are used interchangeably. A wide range of cleaning methods using different mixtures containing nitric, phosphoric and other acids or simply exposing cleaned stainless fittings to air for a period of time will result in a "passivated" condition. For properly cleaned fittings, it is impossible to determine the method of cleaning or passivation that was used. AN/MS/NAS fittings sold by SUNCOR have been cleaned, descaled, and passivated to the applicable engineering specifications.
PASSIVE FILM
The major characteristic of stainless is its ability to form a thin layer of protection called a "passive film" on its outside surface. This film results from a continual process of low-level oxidation, so oxygen from the atmosphere is needed for the passive film to exist. Once formed, it prevents further oxidation or corrosion from occurring. Even if chipped or scratched, a new passive film on stainless will form.
PICKLING
Removing surface impurities by using chemicals. Used mainly to clean parts prior to coating. This treatment is more aggressive than passivation.
PITTING CORROSION
Pitting indicates deep corrosion in localized spots on a fastener. Dirt or grease on certain portions of a fastener may block oxygen from that surface, thus impeding the passive film which protects stainless from corrosion.
PROOF LOAD
A test load that a fitting must undergo without showing significant deformation. It is usually 50% +of yield strength.
SOLUTION ANNEALED (same as CARBIDE SOLUTION ANNEALED)
A process of heating and removing carbide precipitants (carbon that has broken loose from its stainless steel solution) by heating a finished fitting to over 1,850 degrees F. and cooling it quickly, usually in water, so carbon content goes back into the stainless solution.
THREADS
Class 1 threads are a loose tolerance. Class 2 threads comprise 90% of stainless fittings and are normal commercial tolerance. Class 3 threads have a stricter tolerance and tighter fit such as socket cap and set screws. No definite relationship exists between tensile strength and tightness or looseness of fit. The symbol "A" added to threads, such as 2A, means external threads (screws), and "B" means internal (nuts).
WLL
Stands for "Work Load Limit", this is the recommended weight limit for safe use of a product.
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