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The Glossary of Foundry and Casting
(F-G-H-I)

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

Fabrication
The joining, usually by welding, of two or more parts to produce a finished assembly. The components of the assembly may be a combination of cast and wrought materials.

Facing
Refractory material applied to the face of a mold. See Mold, Refractory.

Facing Sand
Specially prepared molding sand used in the mold adjacent to the pattern to produce a smooth casting surface. See Molding Sand.

False Cheek
A cheek used in making a three-part mold in a two-part mold.

Fatigue
The loss of load-bearing ability of a material under repeated load application, as opposed to a single load.

Fatigue Crack
A fracture starting from a nucleus where there is an abnormal concentration of cyclic stress, and propagating through the metal. Surface is smooth and frequently shows concentric markings with a nucleus as the center.

Fatigue Limit (Endurance Limit)
Maximum stress that a material will endure without failure for an infinite number of load cycles.

Fatigue Strength
Maximum stress that a material will endure without failure for a specified number of load cycles.

Feed Head
A reservoir of molten metal provided to compensate for contraction of metal as it solidifies, by the feeding down of liquid metal to prevent voids. Also called a riser. See Riser.

Feed Material
The volume of molten metal from which a casting feeds as it shrinks (contracts) during solidification.

Feeder
Sometimes referred to as a riser. A vertical channel in the mould (part of the runner system) which forms the reservoir of molten metal necessary to compensate for losses due to shrinkage as the metal solidifies. See Riser.

Feeding
Supplying additional molten metal to a casting to make up for volume shrinkage during casting solidification. See Solidification.

Ferric Oxide
Red iron oxide, Fe2O3, commonly available as hematite ore. Used in ground form in cores and molds to increase hot compressive strength.

Ferrite
Iron practically carbon-free. It forms a body-centered-cubic-lattice and may hold in solution considerable amounts of silicon, nickel, or phosphorus; hence the term is also applied to solid solutions in which alpha or delta iron is the solvent.

Ferritic steels
Steels in which ferrite is the predominant phase. These steels are magnetic.

Ferroalloys
Alloys consisting of certain elements combined with iron, and used to increase the amount of such elements in ferrous metals and alloys. In some cases the ferroalloys may serve as deoxidizers. See Alloy.

Ferromagnetic
The ability to become highly magnetic and have the ability to retain a permanent magnetic moment. The elementary magnetic dipoles inside the domain are all oriented in a direction parallel to each other.

Ferrophosphorus
An alloy of iron and phosphorus containing about 70% iron and 25% phosphorus. See Alloy.

Ferrostatic Pressure
Pressure induced by a head of liquid iron or steel.

Fettle
A British term meaning the process of removing all runners and risers and cleaning off adhering sand from the casting. Also refers to the removal of slag from the inside of the cupola and in Britain to repair the bed of an open hearth. See Casting, Risers, Runners.

Fillet
A concave corner piece, often a preformed strip of leather or wax, used on foundry patterns used at the intersection of two surfaces to round out a sharp corner.

Filter
The filtering out of unwanted gases in the casting, at pouring off portion of making the casting.

Fin
A thin projection of metal from the casting, formed as a result of imperfect mold or core joints. See Casting, Core.

Fines
Sand grain sizes substantially smaller than the predominating grain sized in a molding sand; also material remaining on 200- and 270-mesh sieves and pan after tests for grain size and distribution.

Finish (machine)
Amount of metal allowed for machining.

Finish (verb)
The hand work on a mold after the pattern has been withdrawn. See Mold, Pattern.

Finish Allowance
The amount of stock left on the surface of a casting for machining.

Finish Mark
A symbol (f, f1, f2, etc.) appearing on the line of a drawing that represents the edge of the surface of the casting to be machined or otherwise finished.

Finish Welding
Production welding carried out in order to ensure the agreed quality of the casting.

Finite Difference Analysis (FDA)
A computerized numerical modeling approach for solving differential equations. Used primarily in solving heat transfer and solidification problems.

Finite Element Analysis (FEA)
A computerized numerical analysis technique used for solving differential equations to primarily solved mechanical engineering problems relating to stress analysis.

Firebrick
Brick made of refractory clay or other material which resists high temperatures.

Fireclay
A type of clay which is resistant to high temperatures.

Firecracker Core
See Pencil Core.

Flame Hardening
A surface hardening process involving localized flame heating to above the austenite transformation temperature, Ac3, followed by quenching. See Ac3.

Flaring
Term used in connection with zinc-bearing alloys, particularly manganese bronze, to denote evolution of zinc oxide fumes during melting.

Flash
Thin fin or web of metal extending from the casting along the joint line due to the cope and drag not matching completely or where core and coreprint do not match.

Flask
A metal or wood rigid frame without top and without fixed bottom used to hold the sand of which a mold is formed; usually consisting of two parts, cope and drag. See Cope, Drag, Mold.

Flask Bar
A reinforcing member attached within either half of a flask to assist in holding the rammed sand in position. See Flask, Ramming.

Flask Clamp
A device for holding together the cope, drag, and cheek of a flask.

Flask Pin Guides
Guides used to accurately align the match plate pattern in the flask and flask to flask location.

Flask Pins
Assure proper alignment of cope and drag molds after the pattern is withdrawn. See Cope, Drag, Mold, Pattern.

Flask, Slip
A removable flask which can be stripped vertically from the mold. See Flask.

Flask, Snap
A hinged flask which can be removed from the mold after completion.

Flask, Tight
Flask which remains on the mold. See Flask.

Flat/Knife Gate
Wide gate with narrow opening into the mold. It is used to pour thin, flat castings. See Gate.

Flat Back
A pattern with a flat surface at the joint of the mold. It lies wholly within the drag or cope, and this joint of the mold is a plane surface. See Cope, Drag, Mold, Pattern.

Flowability
Property of a foundry sand mixture which enables it to fill pattern recesses and move in any direction against pattern surfaces under pressure.

Flow-Off
Large vent, usually located at the high point of a mold cavity. In addition to letting air and mold gases escape during a pour, the flow-off fills with metal and is allowed to run or flow during the final stage of pouring. See Mold Cavity.

Fluidity
Ability of molten metal to flow readily; usually measured by the length of a standard spiral casting.

Fluidize
To impart fluid like properties to powders or sands e.g. fluidized beds.

Fluorescent Crack Detection
Application of penetrating fluorescent liquid to a part, then removing the excess from the surface, which is then exposed to ultraviolet light. Cracks show up as fluorescent lines.

Flux
Any substance used to promote fusion. Also any material which reduces, oxidizes, or decomposes impurities so that they are carried off as slags or gases.

Follow Board
A board shaped to the parting line of the mold. See Mold, Parting Line.

Founding
The art and science of melting and casting of metals and alloys into useful objects that serve the needs of industry. It is better known as metal casting.

Foundry (Foundries, plural)
The act, process, or art of casting metals. The buildings and works for casting metals.

Foundry Ladle
A vessel for holding molten metal and conveying it from cupola to the molds. See Cupola, Mold.

Foundry Returns
Metal in the form of sprues, gates, runners, risers and scrapped castings, with known chemical composition that are returned to the furnace for remelting. Sometimes referred to as "revert ".

Foundry Sand
Foundry sand is used in creating cores and molds used in the casting of iron, steel, copper and aluminum products. In construction, steel and iron beams-known as girders-are used in the building of bridges, large office buildings and some homes. Copper pipes, aluminum supports and even the hardware and hand tools used in construction had their origins at the foundry. Foundry sand is the second largest industrial use of sand in terms of tons consumed. See Casting, Core, Molds.

Free On Board (F.O.B.)
This is a historical transportation industry term. It deals with who pays the shipping charges on goods produced. The term is a pricing agreement which does not include the carriage charges, from the seller, to the buyer of a product. The seller absorbs the freight charges, the carriage charges, the destination charges, the shipping charges, etc., whatever you wish to call the expense to move the material from the seller to the buyer. There may well be third party billing of these carriage charges. The seller may well have incorporated these charges in the selling price, but does not invoice the buyer for that fee. Remember..."Free On Board," equates to a remembrance thought factor of ..."Free Onto The Buyer"...or F.O.B. as the early traffic managers so coined the term.

Freezing
Term used to denote the solidification process. See Solidification.

Frictional Wear
The displacement and/or detachment of metallic particles from a surface as a consequence of being in contact with another moving component.

Froude Number
Used in hydraulics as an analog to the Reynolds number. It is the ratio of inertial forces to gravitational forces.

Furans
Generic term for a family of chemical compounds including furfural and furfuryl alcohol sued as binders for core sands.

Fusion
Change from a solid to a fluid state caused by application of heat.

Gage Length
The original length of that portion of the specimen over which strain or change of length is determined.

Gage Marks
Reference marks; in tensile testing, the marks which indicate the gage length, used in determination of tensile elongation.

Gagger
A metal piece of irregular shape (usually an L shape) used to reinforce and support sand in deep pockets of molds. There are two types; straight or hooked (cast or steel rods).

Gaging
Checking dimensional requirement by means of a gage.

Gamma iron
One of the allotropic (polymorphic) forms of iron which crystallizes in the face-centered-cubic lattice form. When pure, its range of stability is from 1,670°F to 2,552°F (910°C to 1400°C).

Gannister
An acid (silicious) refractory often used in furnace linings.

Gas Holes
Rounded cavities caused by generation or accumulation of gas or entrapped air in a casting; holes may be spherical, flattened or elongated.

Gas Porosity
A condition existing in a casting caused by the trapping of gas in the molten metal, or by mold gases evolved during the pouring of the casting.

Gate
Specifically, the point at which molten metal enters the casting cavity. Sometimes employed as a general term to indicate the entire assembly of connected columns and channels carrying the metal from the top of the mold to that part forming the casting cavity proper. This term is also applied to pattern parts that form the passages, or to the metal that fills them.

Gated Patterns
One or more patterns with gating systems attached. See Gate, Pattern.

Gating System
The complete arrangement of gates, runners, and sprues through which molten metal flows into the cavity of the mold. See Cavity, Gate, Molds, Runners, Sprues.

Gilsonite
Natural black lustrous asphalt found in the Uinta Mountains in Utah and also known as uintaite. It is used as a carbonaceous addition to foundry sands.

Gooseneck
The pressure vessel or metal injection mechanism in a hot-chamber-type die-casting machine.

Gouging Abrasion
Abrasion involving gross surface indentation and possible removal of sizable metal fragments.

Grade
The grade of an iron, usually given by three successive numbers, the first being the tensile strength (KSI), the second the yield strength (KSI), and the third the elongation (%).

Grain Fineness Number
A system developed by AFS for rapidly expressing the average grain size of a given sand. It approximates the number of meshes per inch of that sieve that would just pass the sample if its grains of uniform size. It is approximately proportional to the surface area per unit of weight of sand, exclusive of clay.

Grain Refiner
Any material added to a liquid metal or alloy or treatment which produces a finer grain size in the subsequent solid.

Grains
Crystals in metals and alloys.

Granular Fracture (Crystalline fracture)
A type of irregular surface produced when metal is broken.

Granular Pearlite
A structure formed from ordinary lamellar pearlite by long annealing at a temperature below but near to the critical point, causing the cementite to spheroidize in a ferrite matrix.

Graphite
Native carbon in hexagonal crystals, also foliated or granular massive, of black color with metallic luster, and soft. Used for crucibles, foundry facings, lubricants, etc. Also made artificially by passing alternating current through a mixture of petroleum coke and coal tar pitch. See Coke, Crucible.

Graphite, Primary
Carbon precipitated as graphite flakes while the iron cools through the freezing eutectic in which austenite, graphite, molten iron, and carbide exist together. Usually with reference to white fracture cast iron.

Graphite, Secondary
Graphite formed by decomposition of austenite during slow cooling of cast iron.

Graphitization
The decomposition of carbide to give free carbon as graphite or as temper carbon.

Graphitizer
Any substance, such as silicon, titanium, aluminum, etc., which promotes the formation of graphite in cast iron compositions.

Gray Iron
Iron in which a large percentage of the carbon content is in the form of graphite flakes. Traditionally referred to as “Cast Iron”. The graphite flakes cause it to have low shock resistance, but high damping ability. It has a gray fracture. Gray Iron is by far the oldest and most common form of cast iron. As a result, it is assumed by many to be the only form of cast iron and the terms "cast iron" and "gray iron" are used interchangeably. Cast iron containing graphite in flake form and typically consisting of 2 to 4 percent carbon and 1 to 3 percent silicon. Gray iron is widely used for engine components in automobiles and trucks. See Cast Iron.

Gray Iron Meltimg
The process of melting gray iron, especially as it is done in a foundry on a commercial scale. See Gray Iron.

Gray Iron Quality Control
The application of quality control practices to the manufacture of gray iron. See Gray Iron.

Green Permeability
Property of a molded mass of sand in its tempered condition which is a measure of its ability to permit the passage of gases through it.

Green Sand
Natural sands combined with water and organic additives, such as clay, to proper consistency for creating molds. See Core, Molds, Natural Sand.

Green Sand Core
A core that is made of molding sand but not baked.

Green Strength
Tenacity (compressive, shear, tensile, or transverse) of a tempered sand mixture at room temperature.

Grinding
Removing gate stubs, fins, and other projections on castings by an abrasive wheel. See Casting, Gate, Fins.

Growth
With reference to cast iron, permanent increase in volume that results from continued or repeated cyclic heating and cooling at elevated temperatures. For unalloyed iron, temperature is in excess of 900° F, and growth is cause by decomposition or graphitization of carbides and by oxidation of the graphite. See Cast Iron.

Guide Pin
The pin on a flask used to locate the cope in the proper place on the drag; also used to locate cheeks. See Cope, Cheek, Drag, Flask.

Gypsum Cement
Calcined calcium sulfate, commonly called plaster of Paris.

Hadfield Manganese Steel
A specialty steel which is austenitic and usually contains approximately 12% Manganese. It is used in mining, earth- moving equipment and in railroad track work.

Hand Ladle Or Shank
A small ladle carried by one man. See Ladle.

Hard Sand Match (Match Plate)
A body of sand shaped to conform to the parting line upon which a pattern is laid in starting to make a mold. Sand is made hard by addition of linseed oil and litharge, Portland cement, etc. See Match.

Hardenability
In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.

Hardness
Resistance of a material to indentation as measured by such methods as Brinell, Rockwell, and Vickers. The term hardness also refers to stiffness of a material, or its resistance to scratching, abrasion, or cutting. See BHN, Brinell Hardness, Vickers Diamond.

Hardness/Brinell
Relative term referring to the resistance of a metal to plastic deformation from a given standard load applied on a standard penetration head. See BHN, Brinell Hardness, Vickers Diamond.

Head
The pressure exerted by a column of fluid, such as molten metal, water, etc.

Head Metal
The reservoir of metal in the feeder or riser of a mold. See Mold, Riser.

Heap Sand
Sand in piles on the foundry floor.

Hearth
That portion of a reverberatory furnace on which the molten metal or bath rests.

Heat
A single furnace charge of metal to be used for pouring directly into mold cavities; a heat may be all of part of a master heat. See Mold Cavity.

Heat Transfer
Transmission of heat from one body to another by radiation, convection, or conduction.

Heat Treatment
A combination of heating and cooling operations timed and applied to a metal or alloy in the solid state in a manner which will produce desired properties.

Heel
Metal left in a ladle after pouring, or in a furnace after or between tapping.

High Pressure Mold
A strong high-density mold, made by air, hydraulic, or other squeeze process.

High Stress Grinding Abrasion
Abrasion that occurs when the abrasive is crushed between two opposing surfaces.

High-Alloy Steel
Ferrous alloy with more than 12 weight percent of noncarbon additions.

Hindered Contraction
Casting contraction during solidification and cooling which is hindered by mold or core restraints.

Holding Furnace
Usually a small furnace for maintaining molten metal at the proper pouring temperature, and which is supplied from a large melting unit.

Holding Ladle
Heavily lined and insulated ladle in which molten metal is placed until it can be used. See Holding Furnace.

Hollow Drill Test (Trepanning)
Removing a cylindrical sample from a metal section or structure to determine soundness of the section.

Homogenizing
A process of heat treatment at high temperature intended to eliminate or decrease chemical segregation by diffusion.

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

Horn Gate
Curved gate in the shape of a horn arranged to permit entry of molten metal at the bottom of the casting cavity. See Casting, Cavity, Gate.

Hot Box Process
Method of making and curing cores within a heated corebox. To form and cure the core, the corebox is heated to approximately 500 degrees F. The sand used in this process contains a catalyst which hardens the binders in the core upon contact with the hot corebox. Complete curing while the core is still in the box results from the residual heat in the core, eliminating the need for conventional dryers or ovens. Frequently, cores created with the Hot Box process are shell cores. See Core.

Hot Deformation (Sand)
Change of form of a sand specimen which accompanies the determination of hot strength.

Hot Shortness
Brittleness in metal at elevated temperature.

Hot Spots
Areas of extra mass usually found at the junction of sections.

Hot Strength (Sand)
Tenacity (compressive, shear or transverse) of a sand mixture determined at any temperature above room temperature.

Hot Tear
Irregularly shaped fracture in a casting formed prior to completion of metal solidification resulting from stresses set up by steep thermal gradients within the casting during solidification and too much rigidity of the core or mold material. See Core, Solidification.

Hot Tears
Cracks in metal castings formed at elevated temperatures by contraction stresses. See Casting.

Hotbox Process
A furan resin based process which uses heated metal coreboxes to produce cores. See Core Box, Furans.

HSLA
Abbreviation for high strength low alloy steel. Steel with relatively high strength and impact properties. The carbon level is low and the alloying additions are significantly less than 5 weight percent.

Hunter Molding
Hunter molding is a sand molding process used to make sand molds. Hunter molding is yet another sand molding process named after the company that makes the machine, Hunter Automated Machinery Corporation. Hunter molding machines are horizontally parted matchplate molding machines, as opposed to the Disamatic vertically parted machines. See Disamatic Molding.

Hydrogen Embrittlement
A condition of low ductility resulting from the absorption of hydrogen. A time dependent fracture process which results in a loss of ductility. See Ductility.

Hypereutectic Alloy
An alloy containing more than the eutectic amounts of the solutes. Analogous to hypereutectiod. See Alloy.

Hypereutectoid
An alloy containing more than the eutectic composition. See Alloy, Eutectic.

Hypereutectoid Steel
A steel containing more than the eutectoid percentage of carbon (0.83 wt. %). See Eutectic.

Hysteresis (Cooling Lag)
Difference between the critical points on heating and cooling due to tendency of physical changes to lag behind temperature changes.

ID Grinding
Term for internal dimension grinding.

Ideal Critical Diameter, D1
The largest diameter of a bar which, upon quenching in an ideal quench, will exhibit 50% martensite at the center of the bar. See Quenching.

Ideal Quench
A quench in which the temperature of an object being quenched instantaneously drops to that of the quench bath and remains constant. See Quenching.

Illinois Inclusion Count Method
A determination of the index number of cleanliness of steel. See Inclusion.

Illite
A mineral, typically KAl 3Si 3O 10(OH)2, found in many clays, large working of which are found in Illinois and Michigan.

Impact Strength
The resistance to impact loads; usually expressed as the foot pounds of energy absorbed in breaking a standard specimen. See Charpy Impact Test.

Impact Value
Total energy needed to break a standard specimen by a single blow under standard conditions; e.g. Charpy Impact Test.

Impoverishment
Loss of any constituent from an alloy or from localized areas of an alloy by oxidation, liquidation, volatilization, or changes in the solid state. The term depletion is also used, particularly in referring to the lowering of the concentration of solute in a solid solution, around particles precipitated from solid solution.

Impregnation
A treatment process using a sealing medium for salvaging leaky castings by injecting under pressure liquid synthetic resins, tung oil, etc., into the porous area. This material is then solidified in place by heating or baking. Other mediums used include silicate of soda, drying oils with or without styrene, plastics, and proprietary compounds.

Impression
Cavity in a die-casting die or in a mold. See Cavity, Mold.

Impurity
An element unintentional allowed in a metal or alloy. Some impurities have little effect on properties; others will grossly damage the alloy.

Inclusion(s)
Particles of slag, refractory materials, sand or deoxidation products trapped in the casting during solidification. See Dirty Casting, Solidification.

Inconel
An oxidation-resistant alloy, 80% Ni, 14% Cr, and 6% Fe.

Indentation Hardness
The resistance of a material to indentation. This is the usual type of hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load. See BHN, Brinell Hardness, Hardness.

Indirect-Arc Furnace
An AC, Alternating Current, electric-arc furnace in which the metal is not one of the poles. An electric furnace in which the arc is struck between two horizontal electrodes, heating the metal charge by radiation.

Induction Furnace
An AC melting furnace which utilizes the heat of electrical induction.

Induction Hardening
A surface hardening process involving the localized use of pulsating magnetic currents to achieve heating above the austenite transformation temperature, Ac3, followed by quenching. See Ac3, Quenching.

Induction Heating
Process of heating by electrical resistance and hysteresis losses induced by subjecting a metal to the varying magnetic field surrounding a coil carrying an alternating current.

Inert Gas
A gas that will not support combustion or sustain any chemical reaction; e.g., argon or helium.

Infrared Dryer
A core or mold dryer employing infrared lamps. See Core Dryers.

Infrared Radiation Pyrometer
This instrument which uses the ratio of the radiated energy from a body in two wavelength bands and then is a measure of the body's surface temperature. Temperatures down to 200°C (392°F) may be measured. See Pyrometer.

Infrared Rays
Pertaining to or designating those rays which lie just beyond the red end of the visible spectrum, such as are emitted by a hot non-incandescent body. They are invisible and nonactinic and are detected y their thermal effect. Their wave lengths are longer than those of visible light and shorter than those of radio waves. Can be applied in the foundry for drying or core baking operations and for heating dies. Infrared radiant heat are synonymous. See Foundry.

Infusorial Earth (Diatomite, Fossil flour, Mountain meal, Mountain flour, Tripolite, Kieselguhr)
A very fine whitish powder composed of the siliceous skeletons of infusorians (Protozoa).

Ingates
The channels through which molten metal enters the mold cavity. See Gate.

Ingot
Casting to be later forged or hot worked. Also, a form used for convenient handling of cast iron, aluminum, and other commercial metals. i.e., Pigs. See Cast Iron.

Ingot Iron
Iron of comparatively high purity produced in open-hearth furnace under conditions that keep down the carbon, manganese, and silicon content; e.g., Armco Iron. See Cast Iron.

Injection
Forcing molten metal into a die-casting die. Also refers to forcing oxygen, nitrogen, and other gases, as well as solids such as calcium carbide and graphite, into molten metal.

Injection Molding
The injection of molten metal or other material under pressure into molds. See Molds.

Inoculant
Materials, which when added to molten metal, modify the structure and thereby change the physical and mechanical properties.

Inoculation
A process of adding some material to molten metal in the ladle for the purpose of controlling the structure to an extent not possible by control of chemical analysis and other normal variables.

Insert
A part usually formed from metal, which is placed in a mold and may become an integral part of the casting. See Casting, Mold.

Insulating Pads And Sleeves
As opposed to chills, insulating material, such as gypsum, diatomaceous earth, etc., used to lower the rate of solidification. As sleeves on open risers, they are used to keep the metal liquid, thus increasing the feed efficiency. See Solidification.

Insulating Sleeve
Hollow cylinders or sleeves formed of gypsum, diatomaceous earth, pearlite, vermiculite, etc. Placed in the mold at sprue and riser locations to decrease heat loss and rate of solidification of the metal contained in them. See Riser, Sprue.

Integral Dose (Volume Dose)
A measure of the total energy absorbed by man or any object during exposure to radiation.

Intensity (Radiology)
Amount of energy per unit time passing through a unit area perpendicular to the line of propagation at the point in question. Often this term is used incorrectly in the sense of dose rate.

Intercast Process
A patented procedure for die casting "cast-assemble" units with moving parts.

Intercrystalline Failure
Cracks or fractures that follow along the grain boundaries in the microstructure of metals and alloys.

Interdendritic Attack
A type of electrochemical corrosion that sometimes occurs in as-cast alloys or alloys that have had very little working.

Intergranular Corrosion
Corrosion in a metal taking place preferentially along the grain boundaries.

Internal Chills
Solid pieces of metal or alloy, similar in composition to the casting, placed in the mold prior to filling it with molten metal. They increase the rate of solidification in their areas and are employed only where feeding is difficult or impossible.

Internal Friction
Ability of a metal to transform vibratory energy into heat; generally refers to low stress levels of vibration; damping has a broader connotation since it may refer to stresses approaching or exceeding yield strength.

Internal Shrinkage
A void or network of voids within a casting caused by inadequate feeding of that section during solidification. See Solidification, Void.

Internal Stresses (or Thermal stresses)
Generally stresses which occur during the cooling of a part.

International Molders & Allied Workers Union of America
International Molders & Allied Workers Union of America - see trade associations.

Interrupted Quench
Removing the casting from a quenching bath before it has reached the temperature of the bath. See Quenching.

Invar
An alloy having practically no expansion when heated; 36% Ni, 0.5% Mn, 0.2% C, and the balance Fe.

Inverse Chill
A condition in an iron casting section in which the interior is mottled or white while the outer sections are gray. This condition is also called reverse chill, internal chill, or inverted chill.

Inverse Segregation
A concentration of certain alloy constituents that have lower melting points in the region corresponding to that first solidifying; caused by interdendritic flow of enriched liquid through channels where the pressure drops with contraction of dendrites. The internal evolution of hydrogen may also give a positive pressure, aiding this flow and causing a liquidated surface as tin sweat. See Segregation.

Inversion
A change in crystal form without change in chemical composition, as from quartz to cristobalite.

Inversion Casting
The metal is fed through a bottom feeder, the mold being inverted for pouring.

Investing
The process of pouring the investment slurry into the flask surrounding the pattern to form the mold. See Flask, Mold.

Investment
A flowable mixture of a graded refractory filler, a binder and a liquid vehicle which when poured around the patterns conforms to their shape and subsequently set hard to form the investment mold. See Investment Casting.

Investment Casting
A pattern casting process in which a wax or thermoplastic pattern is used. The pattern is invested (surrounded) by a refractory slurry. After the mold is dry, the pattern is melted or burned out of the mold cavity, and molten metal is poured into the resulting cavity. See Lost Wax Process.

Investment Casting Process
A pattern casting process in which a wax or thermoplastic pattern is used. The pattern is invested (surrounded) by a refractory slurry. After the mold is dry, the pattern is melted or burned out of the mold cavity, and molten metal is poured into the resulting cavity. See Mold Cavity.

Investment Molding
Method of molding using a pattern of wax, plastic, or other material which is "invested" or surrounded by a molding medium in slurry or liquid form. After the molding medium has solidified, the pattern is removed by subjecting the mold to heat, leaving a cavity for reception of molten metal. This is also called the lost-wax process or precision molding. See Lost Wax Process, Investment Casting.

Investment Precoat
An extremely fine investment coating applied as a thin slurry directly to the surface of the pattern to reproduce maximum surface smoothness. The coating is surrounded by a coarser, cheaper, and permeable investment to form the mold. See Dip Coat.

Inwall Brick
Refractory lining of the inwall section of blast furnace or cupola. See Blast Furnace, Cupola, Refractory.

Ionization
The process or the result of any process by which a neutral atom or molecule acquires either a positive or a negative charge.

Ionization Chamber
An instrument designed to measure quantity of ionizing radiation in terms of the charge of electricity associated with ions produced within a defined volume.

Iridium
A noble metal of the platinum group. Usually extensively as a radiation source. For radiography of thin walled castings.

Iron
A metallic element, mp 1535°C (2795°F). Also irons that do not fall into the steel categories, such as Gray Iron, Ductile Iron, Malleable Iron, White Iron, Ingot, and Wrought Iron. See Gray Iron, Ductile Iron, Malleable Iron, White Iron, Ingot.

Iron Carbide
See Cementite.

Iron Oxide
This material as prepared for foundry use generally contains about 85% ferric oxide and is produced by pulverizing a high grade of pure iron ore. It can be added to core sand mixes to assist in keeping the core from cracking before the metal solidifies during the casting operation and also helps to resist metal penetration during this period. Added to molding sand mixtures for control of finning and veining. Also may reduce carbon pick up.

Iron Sand
See Iserine.

Iron, Hard Or White
Irons (Fe3C) possessing white fracture because all or substantially all of the carbon is in the combined form. Irons to be malleablized are cast white, as are many abrasion-resistant irons.

Iron, Malleable
A mixture of iron and carbon, including smaller amounts of silicon, manganese, phosphorus, and sulfur, which after being cast (white iron, carbon in combined form as carbides) is converted structurally by heat treatment into a matrix of ferrite containing nodules of temper carbon (graphite).

Iron, Pearlitic Malleable
A malleable iron having a more or less pearlitic matrix.

Iron, White Or Hard
Iron of suitable composition in which the castings, later to be malleableized, are originally cast. Carbon is in the combined form; hence it’s white fracture and name.

Iron-Carbon (Graphite) Diagram
A diagram representing stable equilibrium conditions between iron and graphite (pure carbon) phase over the entire range of iron and steel.

Iron-Iron Carbide Diagram
A phase diagram representing metastable equilibrium conditions between Fe and Fe3C over the entire range of carbon steels and cast irons.

Iserine
A black sand which consists mainly of magnetic iron ore but also contains a considerable amount of titanium.

Isocure
Trade name of a binder system developed for use in the cold box process of core construction.

Isocyanate Acid
Isomeric cyanic acid (HNCO).

Isomorphous
Phases with crystal structures of the same type.

Isothermal
Pertaining to changes or other phenomena occurring at a constant temperature.

Isothermal Annealing
A process in which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperature that causes transformation of the Austenite to a relatively soft ferric-carbide aggregate. See Austenite, Annealing.

Isothermal Transformation
The process of transforming Austenite in a ferrous ally to Ferrite or a ferrite-carbide aggregate at any constant temperature within the transformation range. The transformation of one phase in an alloy system to another phase at any constant temperature.

Isotope
One of several different nuclides having the same number of protons in their nuclei, and hence having the same atomic number, but differing in the number of neutrons and therefore in the mass number.

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