ASME B18.12-2020 pdf download

ASME B18.12-2020 pdf download.Glossary of  Termsfor Mechanical Fasteners.
2.7 Terms Relating to Material and Heat Treatment of Fasteners
2.7.1 ALLoy SteeL
alloy steel: a steel to which elements other than carbon have been added to obtain definite mechanical or physical properties, such as higher strength at elevated temperatures, toughness, etc.
2.7.2 AnneaLed
annealed: the state of a fastener achieved by heating the fastener at a given temperature for a given time and cooling it at a given rate to make it soft (i.e., free of hardness caused by working or previous heat treatment).
2.7.3 Carbon SteeL
carbon steel: a steel that does not contain substantial amounts of any alloying material other than carbon.
2.7.4 Case Hardened
case hardened: a fastener of ferrous material whose surface has been made harder than its core. [See also surface heat treatment (para. 2.8.20) and surface treatment (para. 2.8.21).]
2.7.5 CoLd Heading Stock
cold heading stock: material produced under closely controlled manufacturing and inspection methods to be suitable for heading and free from those defects that cause fractures during heading.
2.7.6 Decarburized
decarburized: the surface of a fastener that has a carbon content lower than the carbon content of the core.
2.7.7 Grains
grains.’ individual crystals of a material.
2.7.8 IncLusions
inclusions: particles of nonmetallic impurities contained in material.
2.7.9 Laps
laps: longitudinal surface defects caused by fins or sharp corners folding over into the surface of the material.
2.7.10 Pits
pits: sharp depressions on the surface of a raw material or fastener.
2.7.11 Screw Stock
screw stock: metal in the form of wire or rod that is used for making screw machine parts. It is usually of a free machining type of material.
2.7.12 Soft
soft: the condition of a fastener that, although made from a material that can be — and normally is — hardened by heat treatment, has been left in the as-fabricated temper.
2.7.13 StainLess SteeL
stainless steel: a corrosion-resistant type of alloy steel that contains a minimum of 12% chromium.
2.7.14 Strain Hardening
strain hardening: the increase in hardness, and hence strength, that results from plastic deformation at a temperature below the recrystallization range. Sometimes referred to as “work hardening.’
2.7.15 Temper
temper: the state of a metal or alloy whose structure and mechanical properties have been manipulated by temperature. Temper varies from the annealed temper (soft) to spring temper.
2.7.16 Toughness
toughness: the ability of a material to absorb considerable energy without fracturing.
2.7.17 Voids
voids: internal fissures in ferrous materials. Sometimes referred to as “chrome checks,”“fish eyes,”“shatter cracks,” or UsnowflakesJI
2.7.18 Work Hardening
work hardening: see strain hardening (para. 2.7.14).
2.8 Coatings and Finish TerminoLogy
The following terms are commonly used in designating the various finishes applied to fasteners.
2.8.1 Anodizing
anodizing: the use of an anodic treatment to form an oxide film on a surface. This is commonly used on aluminum.
2.8.2 BLack Oxide
black oxide: a black finish on a fastener produced by immersing it in hot oxidizing salts or salt solutions.
2.8.3 Coating
coating: the application of some material (e.g., a metal, organic compound, etc.) to the surface of a fastener.
2.8.4 Chromate Treatment
chroin ate treatment: the use of a hexavalent chromium compound solution to produce a conversion coating on a fastener.
2.8.5 Dichromate Treatment
dichromate treatment: the use of a hot sodium dichromate solution at a specified temperature to produce a chromate conversion coating on a fastener.
2.8.6 Dry FiLm Lubricant
dryflim lubricant: a dry solid substance that is applied to a fastener surface to reduce friction or wear between the fastener and its mating surfaces. Natural dry film lubricants include graphite and molybdenum disulfide.
2.8.7 Etectrogatvanizing
electroqalvanizing: the process of coating metal with zinc by electroplating.
2.8.8 ELectropLating
electroplating: the process of electrodepositing a metal or alloy on a fastener serving as a cathode.
2.8.9 Finish
finish: the condition of the surface ofa fastener as a result of chemical or organic treatment subsequent to fabrication. The term “finish” is also applied to some types of fasteners to indicate the condition of the surface as a result of mechanical operations and the degree of precision.
2.8.10 FLash PLating
flash plating: the deposit of a very thin layer of metal, whose thickness is in the range of 0.00005 in. to 0.000 15 in (0.000127 cm to 0.000381 cm).
2.8.11 GaLvanizing
galvanizing: the process of coating metal with zinc by hot-dipping or an immersion process. Sometimes referred to as “hot-dip galvanizing.”
2.8.12 MechanicaL PLating
mechanical plating: a process where fine metal powders are peened onto a fastener by tumbling or other mechanical means.