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W
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Chemical symbol for Tungsten, from wolfram. |
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Water Quenching
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A quench in which water is the quenching medium. The major
disadvantage of water quenching is its poor efficiency at the
beginning or hot stage of the quenching process. |
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Welding
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The process of joining together two pieces of metal so that bonding
accompanied by appreciable interatomic penetration takes place at
their original boundary surfaces. The boundaries more or less
disappear at the weld, and integrating crystals develop across them.
Welding is carried out by the use of heat or pressure or both and
with or without added metal. There are many types of welding
including Metal Arc, Atomic Hydrogen, Submerged Arc, Resistance
Butt, Flash, Spot, Stitch, Stud and Projection. |
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Whiskers
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Thin hair-like growths on metal that are barely visible to the naked
eye, they are stronger than the metals from which they are formed,
probably because they are free from defects. |
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White Annealing
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A heat treatment process carried out on pickled steel with the
objective of eliminating the hydrogen that has entered the steel
during the pickling operation and thus removing any tendency to
hydrogen embrittlement. |
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White Layer
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Compound layer that forms as a result of the nitriding process. |
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Widmanstatten Structure
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A microstructure resulting when steels are cooled at a critical rate
from extremely high temperatures. It consists of ferrite and pearlite and has a cross-hatched appearance due to the ferrite
having formed along certain crystallographic planes. |
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Wolfram
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The alternative name for tungsten. |
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Woody Fracture
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A fracture that is fibrous or woody in appearance due to the
elongation of the individual grains. This may be accentuated by the
presence of slag or by a banded structure. It is grey and dull and
is characteristic of ductile but non-homogeneous material such as
wrought iron. |
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Work Hardening
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The increase in hardness and strength produced by cold plastic
deformation or mechanical working. |
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Working Zone
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That portion of the enclosed volume of a piece of thermal processing
equipment occupied by parts or raw material during the soaking
portion of a thermal treatment. It is usually, but not always, a
high percentage of the total enclosed volume. It may include more
than one control zone. |
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Wrought Iron
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A commercial iron that has little use today and has been replaced by
mild steel. It was commonly produced by the puddling process. The
temperatures employed in its production are too low to render it
fluid, it is heated until it forms a pasty mass then it is squeezed
or forged. The process does not lend itself to removal of impurities
so it contains an appreciable quantity of slag. It will not respond
to any heat treatment designed to increase the hardness or strength. |
