The Glossary of Foundry and Casting
(U-V-W-X-Y-Z)

To help metal casting buyers and sellers to understand more about metal casting and foundry operation terms. All terms have been arranged in alphabetical order.

A-B  C-D-E  F-G-H-I  J-K-L-M-N  O-P-Q-R-S-T  U-V-W-X-Y-Z

Ultrasonic Cleaning
Immersion cleaning aided by ultrasonic waves which cause microagitation.

Ultrasonic Testing
A nondestructive method of testing metal for flaws based on the fact that ultrasonic waves are reflected and refracted at the boundaries of a solid medium. Ultrasonic testing is used to detect flaws in materials.

Undercooling
See Supercooling.

Undercut
Part of a mold or die requiring a drawback. See Drawback.

Unkilled Steel
A wild steel insufficiently deoxidized so that it evolves gas and blowholes during solidification. See Killed Steel.

Upgrading
In castings, the removal and repair of discontinuities to raise the quality level of the casting beyond that which can be economically achieved by good foundry practice. See Casting, Foundry.

Upper Yield Point (Also Yield Point)
Denoted in yield point phenomenon as a distinct break from the elastic region accompanied by a drop in load, yet prior to plastic deformation in the stress-strain curve in a low-carbon steel.

Upset
An addition to any flask part to increase height or depth.

Urea Formaldehyde Resin
A thermosetting product of condensation from urea or thio-urea and formaldehyde, soluble in water and used as a sand binder in core and mold compounds.

Vacuum Casting
A casting in which metal is melted and poured under very low atmospheric pressure; a form of permanent mold casting where the mold is inserted into liquid metal, vacuum is applied, and metal drawn up into the cavity. See Cavity, Mold, Mold Casting.

Vacuum Degassing
The use of a vacuum technique to remove dissolved gases such as hydrogen, oxygen, and nitrogen from molten alloys.

Vacuum Melting
Melting, usually by induction heating, in a closed container which is subjected to a vacuum.

Vacuum Refining
Melting in a vacuum, usually by electrical induction, to remove gaseous contaminants from the metal.

Value Analysis
In manufacturing, an analysis to determine the most economical method of manufacturing, taking into account the cost and the process capability of alternate manufacturing systems under consideration, their degree of variation, the benefits of the resultant product, and desired quality and production quantity and rate.

Vanadium
A white, hard, metallic element, mp 1800°C (3272°F), used as an alloy in iron and steel; a powerful carbide stabilizer and deoxidizer.

Vegetable Oils
Oils extracted from plants, used as drying oils in oil core manufacture. Linseed oil is an example.

Veining
Surface defect on castings appearing as veins or wrinkles, which results from cracks in the sand due to elevated temperature conditions and occurs mostly in cores. See Casting, Cores, Defect.

Veins
A discontinuity on the surface of a casting appearing as a raised, narrow, linear ridge that forms upon cracking of the sand mold or core due to expansion of the sand during filling of the mold with molten metal. See Defect.

Vent
Small opening or passage through which gases can escape during the pouring of a mold. It is alco called a vent hole.

Vent Rod
A piece of wire or bar to form the vents in the sand.

Vent Wax
Wax in rod shape placed in the core during manufacture. In the oven the wax is melted out, leaving a vent or passage.

Venting
Perforation with a vent wire of the sand over and around a mold cavity to assist in the escape of the gases.

Vertical Axis Casting Machine
A centrifugal casting machine in which the axis of rotation of the mold is vertical.

Vibrator
A mechanical device, operated by compressed air or electricity, used to loosen a pattern from a mold by jarring or vibration as it is withdrawn from the sand.

Vickers Diamond
The diamon pyramid used in Vickers Hardness Testing. See Vickers Hardness Test.

Vickers Diamond Pyramid Hardness Tester
Patented indentation hardness machine. See Hardness.

Vickers Hardness Test
A method of determining the hardness of steel using a diamond pyramid that is pressed into the polished surface of the specimen and the diagonals of the impression are measured with a microscope fitted with a micrometer eye piece. The rate of application and duration are automatically controlled and the load can be varied. See Vickers Diamond.

Virgin Metal (Primary Metal)
Metal extracted directly from the ore; not previously used.

Viscosity
The resistance of fluid substance to flowing, quantitatively characteristic for an individual substance at a given temperature and under other definite external conditions.

Void
A shrinkage cavity produced in casting during solidification. See Casting, Cavity, Shrinkage, Solidification.

V-Process
A casting technique.

Warm Box Process
Coremaking method in which the corebox is warm when the core sand is introduced. The warmth of the corebox initiates curing but does not complete it. Cores finish curing outside the corebox (sometimes in a separate dryer), allowing for faster core production cycles than with the Hot Box process. Cores created using this process must be solid- they cannot be shell cores. See Cores, Core Box, Hot Box Process.

Warpage
Deformation other than contraction that develops in a casting between solidification and room temperature; also, distortion occurring during annealing, stress relieving, and high-temperature service.

Wash
A casting defect resulting from erosion of sand by metal flowing over the mold or corded surfaces. They appear as rough spots and excess metal on the casting surface. Also call cuts. See Cut, Defect.

Washburn Core
Thin core which constricts the riser at the point of attachment to (Neck-Down Core) the casting. See Casting, Cores, Risers.

Washes
Refractory coating applied to molds and cores to provide protection against penetration from molten metal. See Cores, Molds.

Water Glass
Sodium silicate (an inorganic binder system), a viscous liquid which when mixed with powered fireclay forms a refractory cement.

Water Test
To subject a casting to water pressure in such a manner that any porous areas will show leakage.

Wax
Class of substances of plant, animal, or mineral origin, insoluble in water, partly soluble in alcohol, either, etc., and miscible in all proportions with oils and fats. They consist of esters, free fatty acids, free alcohols, and higher hydrocarbons. Common waxes are beeswax, bayberry, paraffin wax, ozokerite, ceresin, and carnauba. Their mixtures are formed into rods and sheets and used for forming vents in cores and molds, repairing patterns, etc.

Wax Pattern
A precise duplicate, allowing for shrinkage, of the casting and required gates, usually formed by pouring or injecting molten wax into a die or mold. Wax molded around the parts to be welded by a termite welding process.

Weak Sand
Sand lacking in the proper amount of bond. See Bond.

Wear
The undesired deterioration of a component by the removal of material from its surface.

Weld Bead
The built-up portion of a fusion weld, formed either from the filler metal or the melting of the parent metal.

Welding
A process used to join metals by the application of heat. Fusion welding, which includes gas, arc, and resistance welding, requires that the parent metals be melted.

Welding Electrode
A metal or alloy in rod or wire forms used in electric arc welding to maintain the arc and at the same time supply molten metal or alloy at the point where the weld is to be accomplished.

Welding Flash
Skin exposed too long to the ultraviolet rays of welding or melting arcs will burn as in a sunburn. Though temporary blindness can result, it is not permanent, as is popularly believed.

Welding Shielded-Arc
Electric-arc welding in which the molten weld metal is protected from the atmosphere. An inert gaseous atmosphere or fluxcoated electrode may be employed.

Welding Stress
That stress resulting from localized heating and cooling of metal during welding.

Welding, Arc
Welding accomplished by using an electric arc that can be formed between a metal or carbon electrode and the metal being welded; between two separate electrodes, as in atomic hydrogen welding or between the two separate pieces being welded, as in flash welding.

Welding, Autogenous
Method of uniting two pieces of metal by melting their edges together without solder or any added welding metal, as by the thermite process that employs a medium of finely divided aluminum powder and oxide or iron by which a temperature of some 2982.2°C (5400°F) is obtained.

Well (Cupola)
Lower portion of a cupola, between the sand bottom and the slaghole, which forms a reservoir for the molten metal. See Cupola.

Wet Scrubber (Gas Washer)
In air pollution control, a liquid (usually water) spray device for collecting pollutants in escaping foundry gases.

Wetting Agent
Surface-active agent which by reducing surface tension of the wetting liquid causes a material to be wetted more easily.

Whirl Gate
Gating system in which the metal enters a circular reservoir at a tangent, and so whirls around, leaving dirt and slag behind before passing into the mold cavity.

Whistlers
Small openings from isolated mold cavities to allow gases to escape easily. See Vent.

White Cast Iron
Cast iron in which substantially all the carbon is present in the form of iron carbide, and which has a white fracture.

Widmanstatten Structure
Plate-like structure seen in grains of steel in the course of transformation of a solid solution.

Wild Steel
Steel which has not been completely deoxidized and reacts violently after casting due to liberation of gases of cooling.

Wood Flour
Finely ground wood, usually hardwood, low in resin.

X-Ray
A form of radiant energy with extremely short wave length which has the ability to penetrate materials that absorb or reflect ordinary light. X-Rays provide a form of Non-Destructive testing.

Yield
Comparison of finished casting weight verses total weight of metal poured in a mold. A value expressed as a percentage indicating the relationship of the weight of a casting to the total composite of the casting and its gating system.

Yield Ratio
The ratio of yield strength to ultimate tensile strength.

Yield Strength
A measure of the amount of mechanical stress a material can withstand before it permanently deforms.

Zircon
Natural zirconium silicate, ZrSiO4 containing 67.23% zirconium oxide, ZrO4, and 32.77% silica, SiO2, is used as a molding medium in steel foundries.

Zirconia
ZrO2 an acid refractory up to 2,500°C (4,532°F) having good thermal shock resistance and low electrical resistively.

Zirconium
Silvery-white, metallic element, mp 1,860°C (3,380°F), a powerful deoxidizer when added to molten steel.

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