V
Vacuum Degassing
An advanced steel refining facility that removes oxygen, hydrogen and nitrogen
under low pressures (in a vacuum) to produce ultra-low-carbon steel for
demanding electrical and automotive applications. Normally performed in the
ladle, the removal of dissolved gases results in cleaner, higher-quality, more
pure steel (see Ladle
Metallurgy).
Vacuum Oxygen Decarburization (VOD)
A refinement of stainless steel that reduces carbon content. Molten,
unrefined steel is heated and stirred by an electrical current while oxygen
enters from the top. Many undesirable gases escape from the steel and are
evacuated by a vacuum pump. Alloys and other additives are then mixed in to
refine the molten steel further.
Process for further refinement of stainless steel through reduction
of carbon content.
WHY
The amount of carbon in stainless steel must be lower than that in
carbon steel or lower alloy steel (i.e., steel with alloying element content
below 5%). While electric arc furnaces (EAF) are the conventional means of
melting and refining stainless steel, VOD is an economical supplement, as
operating time is reduced and temperatures are lower than in EAF steelmaking.
Additionally, using VOD for refining stainless steel increases the availability
of the EAF for melting purposes.
HOW
Molten, unrefined steel is transferred from the EAF into a separate
vessel, where it is heated and stirred by an electrical current while oxygen
enters from the top of the vessel. Substantial quantities of undesirable gases
escape from the steel and are drawn off by a vacuum pump. Alloys and other
additives are then mixed in to refine the molten steel further.
Vanadium (V)
Chemical symbol V. Element No. 23 of the
periodic system; atomic weight 50.95. Gray-white, hard metal, unaffected by
atmospheric influences or alkalis but soluble in most strong acids; melting
point 3119 (degrees) F.; boiling point about 6150 (degrees) F.; specific gravity
5.87. It cannot be electrodeposited. Its principal functions as an alloy in the
making of tool steels. (1) Elevates coarsening temperature of austenite
(promotes fine grain). (2) Increases hardenability (when dissolved) (3) Resists
tempering and causes marked secondary hardening.
Virgin Metal
Metal obtained directly from ore and not used before.
Vibrated Wound
(See Oscillated Wound Coils)
Vibrator Reed Steel
Hardened, temper and white polished extra precision rolled. Carbon content about 1.00%. Steel must withstand great fatigue stresses.
Vickers Hardness (Test)
Standard method for measuring the hardness of metals, particularly those with extremely hard surfaces: the surface is subjected to a standard pressure for a standard length of time by means of a pyramid-shaped diamond. The diagonal of the resulting indention is measured under a microscope and the Vickers Hardness value read from a conversion table.
Voluntary Restraint Agreements (VRAs)
A compromise reached between the U.S. government and foreign steel-exporting
nations. Instead of the United States imposing punitive duties on subsidized
steel imports, the foreigners would "voluntarily" limit their steel
exports to the United States.
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