Glossary of Metalcasting Terms

This Glossary of Metalcasting Terms provides the casting designer and purchaser with practical definitions of common metalcasting phrases and terms.

 
Aging
A change in properties of metals and alloys which occurs slowly at room temperature and will proceed rapidly at higher temperatures. The change in properties is often, but not always, due to a phase change (precipitation), but never involves a change in chemical composition of the metal or alloy. See also Precipitation Hardening. See also Age Hardening
 
Air Quenching
Accelerated cooling of alloy in an air stream from temperatures above the Ac3 temperature.

Alloy
A substance having metallic properties and composed of two or more chemical elements of which at least one is metal. Usually possesses qualities different from those of the components.

Alloy Steel
Steel containing significant quantities of alloying elements other than carbon and the commonly accepted amounts of manganese, silicon, sulfur, and phosphorus.

Annealing
Heating to and holding at a suitable temperature, followed by cooling at a suitable rate to lower the hardness or alter other mechanical or physical properties.
 
Arc Air Cutting
Using an electric arc to cut metal.
 
Arcair Torch
An electric arc torch with air ducts running parallel to the electrode, used to remove metal and surface defects from ferrous castings.

As Cast (as-cast, u.m.)
Referring to metal which has not received finishing (beyond gate removal or sandblasting) or treatment of any kind including heat treatment after casting. Similarly, as drawn, as forged and as rolled. (See Finishing)
 
Austenite
The face-centered-cubic phase of iron and steel, also referred to as gamma iron. In steel, a solid solution in which gamma iron is the solvent.
 
Bath
Molten metal on the hearth of a furnace, in a crucible, or in a ladle.
 
Batten
A wooden bar or strip fastened to bottom or follow board for rigidity or to prevent distortion during ramming of the mold.

Bentonite
A colloidal clay derived from volcanic ash and employed as a binder in connection with synthetic sands, or added to ordinary natural (clay-bonded) sands where extra strength is required.
 
BHN
Brinell Hardness Number

Bottom Running or Pouring
Filling of the mold cavity from the bottom by means of gates from the runner.
 
Brittle Fracture
Fracture with little or no plastic deformation.

Buring In
See Penetration, Metal
 
Burn
1) Process of cutting metal by a stream of fuel and oxygen, or
2) to permanently damage a metal or alloy by heating to cause either incipient melting or intergranular oxidation.

Burned-On-Sand
A misnomer usually indicating metal penetration into sand resulting in a mixture of sand and metal adhering to the surface of a casting.

Carbide
A compound of carbon with one or more metallic elements.
 
Carbon
Element occurring as diamond and as graphite. Carbon reduces many metals from their oxides when heated with the latter, and small amounts of it greatly affect the properties of iron.

Case Hardening
A process of hardening a ferrous alloy so that the surface layer or case is made substantially harder than the interior or core. Typically case hardening process are carburizing, carbonitriding, and nitriding.

Cementite
A compound of iron and carbon commonly known as iron carbide and having the approximate chemical structure, Fe3C. Cementite is characterized by an orthorhombic crystal structure.
 
Centrifugal Casting
Casting made in molds which are rotating so as to produce a centrifugal force in the molten metal.

Chaplet
Metal support that holds a core in place within a mold; molten metal solidifies around the chaplet and fuses it into the finished casting.
 
Charpy Impact Test
A pendulum-type single-blow impact test in which the specimen, usually notched, is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed in fracture, as impact strength or notch toughness.
 
Cheek
The intermediate section of a flask that is used between the cope and the drag when molding a shape requires more than one parting plane.

Chill (External)
Metal, graphite or carbon blocks that are incorporated into the mold or core to locally increase the rate of heat removal during solidification and reduce shrinkage defects.
 
Chill (Internal)
A metallic device / insert in molds or cores at the surface of a casting or within the mold to increase the rate of heat removal, include directional solidification and reduce shrinkage defects. The internal chill may then become a part of the casting.

Cleaning
The removal of gates, runners and risers from the rough casting. This term also involves any hand finishing such as grinding or blasting.

CMM
Coordinate Measuring Machine.
 
CNC
Computer Numerical Controlled Machine Tools.

Cold Lap
Wrinkled markings on the surface of an ingot or casting from incipient freezing of the surface.
 
Cold Shot
Small globule of metal embedded in but not entirely fused with the casting.
 
Cold Shut
Casting defect caused by imperfect fusing or discontinuity of molten metal coming together from opposite directions in a mold, or due to folding of the surface. It may have the appearance of a crack or seam with smooth, rounded edges. Also see Cold Lap

Comressive Strength (Yield)
The maximum stress in compression that can be withstood without plastic deformation or failure.

Cope
Upper or topmost section of a flask, mold or pattern.
 
Coping Out
The extension of sand of the cope downward into the drag, where it takes an impression of a pattern.

Core
A performed sand aggregate inserted in a mold to shape the interior or that part of a casting which cannot be shaped by the pattern.

Core Binder
Any material used to hold the grains of core sand together.

Core Blow
A gas pocket in a casting adjacent to a core cavity caused by entrapping gases from the core.
 
Core Float
A casting defect caused by core movement towards the cope surface of the mold, as a result of core buoyancy in liquid steel, resulting in a deviation from the intended wall thickness.
 
Core Rod
A wire or rod of steel used to reinforce and stiffen the core.

Core Sand
Sand for making cores to which a binding material has been added to obtain good cohesion and permeability after drying. Usually low in clays.
 
Core Vents
1) holes made in the core for escape of gas.
2) A metal screen or slotted piece used to form the vent passage in the core box employed in a core-blowing machine.
3) A wax product, round or oval in form, used to form the vent passage in a core.

Coreless Induction Furnace
See Induction Furnace

Coremaker
A craftsman skilled in the production of cores for foundry use.
 
Corrosion
1) Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents,
2) chemical attack of furnace linings by gases, slags, ashes or other fluxes occurring in various melting practices.

Cover Core
A core set in place during the ramming of a mold to cover and complete a cavity partly formed by the withdrawal of a loose part of the pattern. Also used to form part or all of the cope surface of the mold cavity. A core placed over another core to create

Crack, Hot Tear
A rupture occurring in a casting at or just below the solidifying temperature by a pulling apart of the soft metal, caused by thermal contraction stresses. See also Quench Crack.
 
Crucible
A ceramic pot or receptacle made of materials such as graphite or silicon carbide, with relatively high thermal conductivity, bonded with clay or carbon, and used in melting metals; sometimes applied to pots made of cast iron, steel, or wrought steel. The

Crush
Buckling or breaking of a section of mold due to incorrect register when closing. Also, an indentation in the casting surface due to displacement of sand in the mold when the mold is closed.

Curing Time (No Bake)
That period of time needed before a sand mass reaches maximum hardness.
 
Decarburiztion
Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium, usually oxygen, that react with carbon.

Defect
A discontinuity in the product whose severity is judged unacceptable in accordance with the applicable product specification.
 
Degasser
A material employed for removing gases from molten metals and alloys.

Degassing
Usually a chemical reaction resulting from a compound added to molten metal to remove gases from the metal. Often inert gases are used in this operation.

Descale
Remove the fire scale from the surface of casting.

Desulfurization
Removal of sulfur from the molten metal by addition of suitable compounds

Deoxidation
Removal of excess oxygen from molten metal, usually accomplished by adding materials with a high affinity for oxygen, the oxides of which are either gaseous or readily form slags.

Die
A metal block used in forming materials by casting, molding, stamping, threading, or extruding.

Die Casting
A rapid, water-cooled permanent mold casting process limited to nonferrous metals.

Dip Tank
A tank, preferably lined with rubber, epoxy, or other nonmetallic, into which diecastings are dipped for cooling after leaving the machine.

Direct-Arc Furnace
An electric arc furnace in which the metal being melted is one of the poles.

Downgate
See Downsprue

Downsprue (Sprue, Downgate)
The first channel, usually vertical, which the molten metal enters; so called because it conducts metal down into the mold.

Draft, Pattern
See Pattern Draft
 
Drag
Lower or bottom section of a mold or pattern.
 
Draw
A term used for
1) to temper,
2) to remove pattern from mold,
3) an external contraction defect on surface of mold.

Drop (Dropout)
A casting defect caused by sand dropping from the cope or other overhanging section.
 
Dry Permeability
The property of a molded mass of sand bonded or unbonded, dried at 220-230°F (105-110°C) and cooled to room temperature that allows passage of gases resulting during pouring of molten metal into a mold.
 
Ductile Iron
See Nodular Iron
 
Elasticity
The property of recovering original shape and dimensions upon removal of a deforming force.

Electrode
Compressed graphite or carbon cylinder or rod used to conduct electric current in electric arc furnaces, arc lamps, carbon arc welding, etc.
 
Elongation
Amount of permanent extension in the vicinity of the fractures in the tensile test; usually expressed as percentage of original gage length.
 
Embrittlement
Loss of ductility of a metal due to chemical or physical change. See Acid Embrittlement and Hydrogen Embrittlement

Erosion
Abrasion of metal or other material by liquid or gas, usually accelerated by pressure of solid particles of matter in suspension, and sometimes by corrosion.

Exothermic
Formed by or characterized by heat reaction as in oxidation.

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

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

Fatigue Crack or Failure
A fracture starting from a nucleus where there is an abnormal concentration of cyclic stress. The fracture surface is smooth and frequently shows concentric (sea shell) markings with a nucleus as a center.

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

Feeding
The process of supplying molten metal to compensate for volume shrinkage while the casting is solidifying.

Ferrite
A solid solution of one or more elements in the body-center-cubic phase of iron or steel.

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

Fettle
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.

Fillet
A concave corner piece used on foundry patterns, a radius joint replacing sharp inside corners.

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.

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

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.

Flash
A thin section of metal formed at the mold, core, or die joint or parting in a casting due to the cope and drag not matching completely or where core and coreprint do not match.

Flask
A metal frame used for making or holding a sand mold. The upper part is the cope and the bottom half is the drag.

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 ".

Gaggers
Metal pieces of irregular shape used to reinforce and support the sand in the mold.

Gate
The end of a runner in a mold where molten metal enters the mold cavity.

Gating System
The complete assembly of sprues, runners and gates in a mold through which steel flows before entering the casting cavity.

Green Sand
A naturally bonded sand or a compounded molding sand mixture which has been tempered with water for use while still in the damp or wet condition.

Green Sand Core
A sand core used in the unbaked condition, also a core made from green sand and used as rammed.

Green Strength
The strength of a tempered sand mixture at room temperature
 
Hadfield Manganese Steel
A specially steel which is austenitic and usually contains approximately 12% Manganese. It is used in mining, earth- moving equipment and in railroad track work.

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.

Heat
The total amount of metal produced which can be represented by one analysis sample and one set of mechanical tests.

Heat Treatment
A combination of heating and cooling operations and applied to a metal or alloy to produce desired properties and microstructures.

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

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

Hot Tear
A crack or fracture formed prior to completion of metal solidification as a result of hindered contraction. A hot tear is frequently open to the surface of the casting and is commonly associated with design limitations.

HSLA
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.

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

Impregnation
The treatment of castings with a sealing medium to stop pressure leaks, such as soaking under pressure with or without prior evacuation and either with hot or cold application. Mediums used include silicate of soda, drying oils with or without styrene, plastics, and proprietary compounds.

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

Inclusions
Nonmetallic materials in a metal matrix. Sources include reoxidation, refractories, slag, and deoxidization products.

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 Brinell Hardness and Hardness

Induction Furnace
A 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.

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.

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

Ingot
A mass of metal cast to a convenient size and shape for remelting or hot working.

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

Inoculant
Material which when added to molten metal modifies the structure, and thereby changes the physical and mechanical properties to a degree not explained on the basis of the change in composition resulting from its use.

Inoculation
Addition to molten metal of substances designed to form nuclei for crystallization. Also see Inoculant.

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

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

Investing
The process of pouring the investment slurry into the flask surrounding the pattern to form the 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.

Investment Casting
The process of casting metal into an investment mold.

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.

Jobbing Foundry
A foundry engaged in the manufacture of numerous types of castings.

Jolt-Squeezer Machine
A combination machine that employs a jolt action followed by a squeezing action to compact the sand around the pattern.
 
Kiln
An oven or furnace for burning, calcimining or drying a substance.

Kiln-Dried
Lumber artificially dried in a specially designed enclosure or lumber kiln.

Kish
Free graphite which separates upon slow cooling of molten hypereutectic iron.

Kissing (Touching)
Gating with minimum metal left at casting breakoff point, having a gate just " kiss " the surface.

Ladle
Metal receptacle frequently lined with refractories used for transporting and pouring molten metal. Types include hand bull, crane, bottom-pour, holding, teapot, shank, lip-pour.

Ladle, Bottom-Pour
Ladle from which metal flows through a nozzle in the bottom.

Ladle, Bull
A large ladle for caring molten metal. Frequently used to designate a transfer ladle.

Ladle, Lip-Pour
Ladle in which the metal is poured over a lip.

Ladle, Teapot
A ladle in which, by means of an external spout, metal is removed from the bottom rather than the top of the ladle.

Lance, Oxygen
A device, consisting of steel pipe, tubing, oxygen source, and controls which uses the heat of burning steel pipe for melting. Frequently used to open frozen tape or slag holes.

Lining
Inside refractory layer of firebrick, clay, sand, or other material in a furnace or ladle.

Lining, Monolithic
A lining made without the customary layers and joints of a brick wall. Usually made by tamping or casting refractory material into place, drying, and then burning in place on the job.

Liquid Penetrant Testing
A nondestructive testing method suitable for evaluating the surface integrity of non-magnetic and ferro-magnetic parts.

Loose Molding
The molding process utilizing unmounted patterns. Gates and runners are usually cut by hand.

Loose Piece
1) Core box: part of the core box which remains embedded in the core and is removed after lifting off the core box.
2) Pattern: laterally projecting part of a pattern so attached that it remains in the mold until the body of the pattern is drawn.
 
Lost Foam Process
Casting process in which a foam pattern is removed from the cavity by the molten metal being poured.

Machine Allowance
Stock added to the part to permit machining of the part to final dimensions.

Machine Drawing
An engineering drawing which depicts the final size and shape of the part for its end use.

Magnetic Particle Inspection
A nondestructive method of inspecting the surface integrity of ferromagnetic materials.

Manganese Steel (Austenitic)
See Hadfield Manganese Steel

Maraging Steel
A high alloyed steel that is hardened by both martensite transformation and by age hardening.

Martensite
A generic term used for microstructures formed by diffusionless phase transformations. A constituent found in hardened steel; has a needle like microstructure. See also Mf and Ms.

Martensitic Stainless Steels
A corrosion-resistant ferrous alloy with a predominant martensitic phase.

Matchplate
A plate of metal or other materials on which patterns and gating systems, split along the parting line, are mounted back to back to form an integral piece.

Mechanical Properties
Properties of a material that reveal its strength and elastic behavior.

Metallurgy
The science and technology of metals, a broad field that includes but is not limited to the study of internal structures and properties of metals and the effects on them of various processing methods.

Microstructure
The structure of polished and etched metal and alloy specimens as revealed by the microscope at magnifications over 10 diameters.

Mild Steel
Plain carbon steel of about 0.25% carbon or less.


Mill Scale
Iron oxide scale formed on steel during hot working processes, cooled in airMilling
Removing metal with a milling cutter.

Misrun
Denotes an irregularity of the casting surface caused by incomplete filling of the mold due to low pouring temperature, gas back-pressure from inadequate venting of the mod, and inadequate gating.
 
Modulus Of Elasticity (E)
In tension it is the ration of stress to the corresponding strain within the limit of elasticity (Yield Point) of a material. For carbon and low alloy steels any composition and treatment, the value is approximately 30,000,000 psi.
 
Moisture Teller
A patented apparatus for the rapid determination of moisture content of molding sand.
 
Mold Cavity
The space in a mold which is filled with liquid metal to form the casting upon solidification. The channels through which liquid metal enters the mold cavity (sprue, runner, gates) and reservoirs for liquid metal (risers) are not considered part of the mold

Mold Coating (Mold Facing, Dressing)
1) Coating to prevent surface defects on permanent mold castings and die castings,
2) coating on sand molds to prevent metal penetration and improve metal finish.

Mold Jacket
A wooden or metal form slipped over a mold to support the side during pouring.

Mold Shift
A casting discontinuity resulting from misalignment of the cope and drag halves.
 
Moldability
Ability of sand to flow into a flask and around a pattern; measured in the amount of sand falling through an inclined screen or slot.

Molding Sands
Sands containing over 5% natural clay, usually between 8 and 20%. See also Natually Bonded Molding Sand.

Molding, Bench
Making sand molds by hand tamping loose or production patterns at a bench without assistance of air or hydraulic action.

Molding, Floor
Making sand molds from loose or production patterns of such size that they cannot be satisfactorily handled on a bench or molding machine, the equipment being located on the floor during the entire operation of making the mold.

Molding, Pit
Molding method in which the drag is made in a pit or hole in the floor.

Muller
A type of foundry sand-mixing machine.

Neck Down (Knock-Off, Wafer Core, Washburn, Cameron Core)
A thin core or tile used to restrict the riser neck, making it easier to break or cut off the riser from the casting. See Core.

Nickel
Element used for alloying iron and steel as well as nonferrous metals; melting point 1455°C (2651°F). Nickel is also a base metal for many casting alloys resistant to corrosion and high temperature oxidation. See Monel, Nimonic, Inconel, Ni-Hard.

Ni-Hard
Hard white cast iron containing 4% Ni and 2% Cr.

Nitriding
A surface hardening process involving heating in a atmosphere of ammonia or in contact with a nitrogen-bearing material so as to promote the absorption of nitrogen.

Nobake Binder
A synthetic liquid resin sand binder that hardens completely at room temperature, generally not requiring baking, used in Cold-Setting process.

Nobake Molding
Where you use a binder that hardens completely at room temperature in your mold media

Nodular Graphite
Graphite or carbon in modular form, characteristically in malleable and nodular iron.

Nodular Iron
Iron of a normally gray cast iron type that has been suitably treated with a nodularizing agent so that all or the major portion of its graphitic carbon has a nodular or spherulitic form as cast. Often referred to as Ductile Iron.

Nondestructive Testing (Inspection) or NDT
Testing or inspection that does not destroy the object being tested or inspected.

Nonferrous
A negative term, refers to alloy in which the predominate metal or solvent is not iron.

Normalizing
Heating a ferrous alloy to a suitable temperature above the transformation temperature Ac3, followed by cooling at a suitable rate, usually in still air to a temperature substantially below the transformation range.

Oil Quenching
Quenching in oil.

Oil Sands
Sand bonded with such oils as linseed and the synthetics.

One-Piece Pattern
Solid pattern, not necessarily made from one piece of material. May have one or more loose pieces.

Open Grain Structure
A defect wherein a casting, when machined or fractured, appears to be coarse grained and porous; usually due to a shrink area.
 
Open Riser
See Riser, Open

Open Sand Casting
A casting produced in an open mold; poured in the drag, with no cope or other top covering.

Openhearth Furnace
A furnace for melting metal, in which the bath is heated by the combustion of hot gases over the surface of the metal and by radiation from the roof.

Optical Pyrometer
A temperature measuring device through which the observer sights the heated object and compares its incandescence with that of an electrically heated filament whose brightness can be regulated
 
Orange Peel
A pebble-grained surface that develops in the mechanical forming of sheet metals with coarse grains.
 
Oxidation
Any reaction of an element with oxygen. In a narrow sense, oxidation means the taking on of oxygen by an element or compound, and on the basis of the electron theory it is a process in which an element loses electrons.

Oxide
A compound of oxygen with another element.
 
Oxidizing Atmosphere
An atmosphere resulting from the combustion of fuels in an atmosphere where excess oxygen is present, and with no unburned fuel lost in the products of combustion.

Oxygen Lance
See Lance, Oxygen

Parted Pattern
A pattern made in two or more parts.

Parting Agent
See Release Agent

Parting Line
A line on a pattern or casting corresponding to the separation between the cope and drag portions of a sand mold.

Pattern
A form of wood, plastic, metal, or other material around which molding material is placed to make a mold.
Ref: http://www.efunda.com/processes/metal_processing/sand_casting_intro.cfm#Patterns

Pattern Draft
The taper on vertical elements in a pattern which allows easy separation of pattern from compacted sand mixture.

Pattern Layout
Full-sized drawing of a pattern showing its arrangement and structure features.

Patternmaker
A craftsman engaged in production of foundry patterns from wood, plastic, or metals, such as aluminum, brass, etc.

Pearlite
A lamella aggregate of ferrite and carbide, the structure of pearlite can appear fine or coarse depending on processing.

Pencil Core
A core projecting to the center of a blind riser allowing atmospheric pressure to force out feed metal.

Perlite
A highly siliceous volcanic rock which can be expended by heating into a porous mass of particles. Perlite can be used as an insulation in foundry sand mixtures. Not to be confused with Pearlite.

Permanent Mold
A mold which can be used repeatedly for the production of many castings of the same form.

Physical Metallurgy
The science concerned with the physical and mechanical characteristics of metals and alloys.

Physical Properties
Properties of a metal or alloy the determination of which does not involve the deformation or destruction of the specimen-for example, density, electrical conductivity, coefficient of thermal expansion, magnetic permeability, and lattice parameter.

Pig Iron, Basic
A grade of iron made from the basic open-hearth process of steelmaking; P, 0.40% max. for Northern iron, 0.70 to 0.90% for Southern iron; S 0.05% max. and Si, 1.50%.

Pilot Casting
Casting produced prior to the production run to verify correctness of procedures, materials, and process to be used in production.

Pipe
A cavity formed by shrinkage of the metal during solidification, usually occurring in a riser having feeder metal for the casting.

Pitting
A form of wear characterized by the presence of surface cavities, the formation of which is attributed to processes such as fatigue, local adhesion, cavitation or corrosion.

Plastic Deformation
Permanent distortion of a material under the action of applied pressure.

Pouring
Transfer of molten metal from furnace to ladle, ladle to ladle, or ladle into molds.

Pouring Cup
The flared section of the top of the downsprue. It can be shaped by hand in the cope, or be a shaped part of the pattern used to form the downsprue; or may be baked core cup placed on the top of the cope over the downsprue.

Precipitation Hardening
A process of hardening an alloy in which a constituent precipitates from a supersaturated solid solution.

Preheating
A general term for heating material, as a die in die casting, as a preliminary to operation, to reduce thermal shock and prevent adherence of molten metal.

Pressure Die Casting
A British term. See Die Casting.

Primary Choke (Choke)
That part of the gating system which most restricts or regulates the flow of metal into the mold cavity.

PugMill
A mill for mixing foundry sands and sand mixtures consisting essential of a shaft fitted with plows or paddle wheel which revolve in a tub or vat.
 
Quenching
Rapid cooling of hardening; normally achieved by immersion of the object to be hardened in water, oil, or solutions of salt or organic compounds in water.

Quench Crack
A crack resulting from thermal stress induced during rapid cooling or quenching, or from stresses induced by delayed transformations some time after the article has been fully quenched.

Quench Severity
The quench severity is characterized by the H value and relates to the rate of temperature change during quenching.

Rapping
Knocking or jarring the pattern to loosen it from the sand in the mold before withdrawing the pattern.

Rare Earth (RE)
Any of a group of 15 similar metals with atomic numbers 57 to 71. Also rare earth element, rare earth metal, lanthanide series, uncommon metals, Mischmetal.

Rat Tail
An expansion discontinuity in a sand casting, featured as a long, narrow, linear depression, resulting from sand expansion and minor buckling of the mold surface during filling of the mold.

Receiving Ladle
A ladle placed in front of the cupola into which all metal is tapped. It acts as a mixer and reservoir and to smooth out metal flow to the pouring area.

Recrystallization
A process whereby the distorted grain structure of cold-worked metals is replaced by a new, strain-free grain structure during annealing above a specific minimum temperature.

Recrystallization Temperature
The lowest temperature at which the distorted grain structure of a cold-worked metal is replaced by a new, strain-free grain structure during prolonged annealing. Time, purity of the metal, and prior deformation are important factors.

Reduction
The removal of oxygen or addition of hydrogen.

Refractory
1) Heat-resistant material, usually non-metallic, used for furnace linings etc.,
2) the quality of resisting heat.

Refractory Clay
A clay which fuses at pce 25 (1590C, 2894F) or higher.

Regression Analysis
A statistical method of determining, or predicting, the value of a dependent variable, based on levels of one or more know independent variables.

Release Agent (Parting Agent)
A material, e.g. silicone, stearate, oil, or wax for lubricating a die pattern or core box to facilitate easy removal of a casting, mold or core.

Remanence
The remaining flux density after the magnetizing force has been removed.

Residual
Any element remaining in any alloy following melting and casting which was not added to meet an analytical specification limit.

Residual Stress
See Stress, Residual

Rigging
Gates, risers, loose pieces, etc., needed on the pattern to produce a sound casting.

Riser
Reservoir of molten metal from which casting feeds as it shrinks during solidification.

Riser Distance
The length of the riser neck. The term is applied to side risers only.

Riser Height
The distance from the top of the riser when liquid to the top of the riser neck. Riser height when sold is usually several inches less than when liquid because of contraction and loss of feed metal to the casting.

Riser Neck
The connecting passage between the riser and casting. Usually only the height and width or diameter of the riser neck are reported, although the shape can be equally important.

Riser Pad (Riser Contact)
An enlargement of the riser neck where it joins the casting. The purpose of the pad is to prevent the riser from breaking into the casting when it is struck or cut from the casting.

Riser, Blind
A riser that does not break through the top of the cope and is entirely surrounded by sand; opened to the atmosphere by means of a firecracker core.

Riser, Open
Conventional form of riser usually located at the heaviest section of the casting and extending through the entire height of the cope.

Riser, Side (Side Head)
A riser attached to the side of a casting.

Riser, Top (Top Head)
A riser attached to the top surface of a casting.

Riser-Gating
Practice of running metal for the casting through the riser to help directional solidification.

Rockwell Hardness
See Hardness

Rodding
Reinforcing the sand in a core with metal rods or shapes to strengthen parts of the core.

Rolling Over
The operation of reversing the position of a flask. If the drag part of the pattern has been rammed with the parting surface downward, it is rolled over 180 degrees to allow core setting and placement of cope.

Rollover Board
A wood or metal plate on which the pattern is laid top face downward for ramming the drag half mold, the plate and half mold being turned over together before the joint is made.

Rollover Machine
A molding machine with which the flask is rolled over before the pattern is drawn from the mold.

Runner
A channel through which molten metal or slag is passed from one receptacle to another; in a mold, the portion of the gate assembly that connects the downgate or sprue with the casting ingate or riser.

Runner Extension
In a mold, that part of a runner which extends beyond the farthest ingate as a blind end. It acts as a dirt trap since the first rush of metal along the runner will pick up any loose particles of sand or dirt and carry them into the extension and not into the mold cavity

Runner Riser
A conventional runner, usually in the horizontal plane, which permits flow of molten metal to the ingate and is large enough to act as a reservoir to feed the casting.

Runout
A casting defect caused by incomplete filling of the mold due to molten metal draining or leaking out of some part of the mold cavity during pouring; escape of molten metal from a furnace, mold or melting crucible.

Sag
A decrease in metal section in casting due to sagging of the cope or core.

Sand
In metalcasting, a loose, granular material high in SiO2, resulting from the disintegration of rock. The name sand refers to the size of grain and not to mineral composition. Diameter of the individual grains can vary from approximately 6 to 270 mesh. Mos

Sand Casting
Metal castings produced in sand molds.

Sand Control
Procedure whereby various properties of foundry sand, such as fineness, permeability, green strength, moisture content, etc., are adjusted to obtain castings free from blows, scabs, veins, and similar defects.

Sand Mulling
A method of evenly distributing the bond around the sand grain by a rubbing action.

Sand Plow
A bladed device used to divert sand from a belt conveyor into a sand hopper.

Sand Porosity
Volume of the pore spaces or folds in a sand. (Not synonymous with permeability).

Sand Reclamation
Processing of used foundry sand grains by thermal, attraction or hydraulic methods so that it may be used in place of new sand without substantially changing current foundry sand practice.

Scab
An expansion discontinuity defect on the surface of a casting which appears as a rough, slightly raised surface blemish, crusted over by a thin porous layer of metal under which is a honeycomb or cavity that usually contains a layer of sand.

Scaling (Scale)
Surface oxidation, partially adherent layers of corrosion products, left on metals by heating or casting in air or in other oxidizing atmospheres.

Scarfing
Cutting off surface projections such as gates and risers from casting by means of gas torch.

Scrap (Metal)
Metal to be remelted; includes scrapped machinery fabricated items such as rail or structural steel and rejected castings.

Screen (Sand)
A sieve or riddle with openings of definite size used to separate one gain size from another or to remove lumps from sand.

Screen Analysis (Sieve Analysis)
Distribution of particle size sand expressed in terms of the percentage of weight retained on each of a series of standard screens decreasing in mesh size and the percentage passed by the screen of finest mesh.

Shakeout
1) The operation of removing castings from the mold 2) a mechanical unit for separating the molding materials from the solidified metal casting.

Shear
A type of deformation in which parallel planes in the metal crystals slide so as to retain their parallel relation.

Shear Strength
Maximum shear stress a material is capable of withstanding without failure.

Shell Molding
A process for forming a mold from resin-bonded sand mixtures brought in a contact with preheated metal patterns.

Shift
A casting defect caused by mismatch of cope and drag or of cores and mold.

Shotbalsting (Shot Peening)
Casting cleaning process employing a metal abrasive (grit or shot) propelled by centrifugal or air force.

Shrink
The difference in volume between liquid metal and solid metal or the void (shrink hole) left in a casting because of it.

Shrinkage
1) Liquid, contraction in volume as metal cools to solidification,
2) solidification, contraction in volume when the metal passes from the liquid to the sold at the freezing point (may expend over a range),
3) solid, the contraction on cooling from freezing

Shrinkage Cracks
Cracks that form in metal as result of the pulling apart of grains by contraction before complete solidification.

Shrinkage, Patternmakers
A linear scale or ruler, typically in inches or millimeters which has been lengthened by the percentage of linear shrinkage by which liquid metal contracts during solidification and cooling.

Sieve Analysis
See Screen Analysis

Silica
Silicon dioxide, the prime ingredient of sand and acid refractories.

Silica Brick
Refractory material of ganister, bonded with hydrated lime, and fired at high temperature.

Silica Gel
A colloidal form of silica used as a drying agent.

Silica Sand
Sand with a minimum silica content of 95% used for forming casting molds.

Silicon
An abundant element, chemically classed as a nonmetal, metallurgically a metal, used extensively in ferrous and nonferrous alloys; melting point 1423°C (2593.4°F)

Skim Core (Skimmer)
A flat core or tile placed in a mold to skim a flowing stream of metal. Commonly used in pouring basins, it hold back slag and dirt while clean metal passes underneath to the downsprue. See Core Strainer.
 
Skim Gate
A gating arrangement which changes the direction of flow of molten metal and prevents the passage of slag and other undesirable materials into the mold cavity.

Skimming
Removing or hold back dirt or slag from the surface of the molten metal before or during pouring.
 
Skin
A thin surface layer different chemically or structurally from the main mass of a metal object.

Slab Core
Flat, plain core.

Slag Inclusion
Nonmetallic solids entrapped in solid metal.

Slag Trap
An enlargement, dam, or extrusion in the gating or runners system in a mold for the purpose of preventing molten slag particles from entering the mold cavity. See also Dirt Trap.

Slicking (Sleeking)
Smoothing the surface of molds.

Slurry
A term loosely applied to any clay-like dispersion. It may be use to wash ladles or other refractory linings to impart a smooth surface; as a bonding addition to molding sand; as a thin loam over specially made molds or as a mixture to fine joints or crac

Smelting
A metallurgical thermal process in which a metal is separated in fused form from nonmetallic materials or other undesired metals with which it is associated.

Sodium Silicate
See Water Glass

Softening
A process used to soften metals through annealing or tempering.

Solidification
The physical process of change from a liguid to a solid state.

Solidification, Shrinkage
The decrease in size accompanying the freezing of a molten metal.

Spalling
Buckling or flaking off of the surface material.

Spheroidite
A cementite aggregate of globular carbide and ferrite.

Spheroidized Cementite (Divorced Pearlite)
The globular condition of iron carbide after a spheroidizing treatment.

Spout
A trough through which the metal flows from the furnace to the ladle.

Sprue Base
An enlargement or rounded section at the bottom of the downsprue, used to help streamline the flow of metal into the runner, lowering the velocity.

Sprue Bottom
A print attached to the top or squeeze board of a mold to make an impression in the cope indicating where the sprue should be cut.

Sprue Cutter
A metal tool used in cutting the pouring aperture, the sprue hole.

Sprue Hole
The opening through which the metal is poured into the cope to run into the casting cavity.

Squeeze Board
A board used on the cope half of the mold to permit squeezing of the mold.

Squeeze Head
In certain type of molding machines, a stationary or movable plate against which a filled mold is compressed, in order to complete the compacting of the sand.

Squeezer Machine
A power-operated, usually pneumatic, device used to pack sand into a flask.

Stack Molding
See Multiple Mold

Stainless Steel
A wide range of steels containing chromium or chromium and nickel, exhibiting high resistance to corrosion.
 
Steel
An alloy of iron and carbon that may contain other elements and in which the carbon content does not exceed about 1.7%; it must be malleable at some temperature while in the as-cast state.

Stock Allowance
Material added to a part to allow for surface preparation or precise dimensioning by machining.
 
Stock Core
Core of standard diameter usually made on a core machine and kept on hand, sawed to required length.

Stopper Rod
A device in a bottom-pour ladle for controlling the flow of metal through the nozzle into the casting. The stopper rod consists of a steel rod, protecting sleeves, and a graphite stopper head. It may also be a single piece manufactured from graphite.

Stopping-Off
Filling in a portion of a mold cavity which is not to be cast.

Strainer Core
See Core Strainer

Strength, Compressive
See Compressive Strength

Strength, Impact
See Impact Strength

Strength, Shear
See Shear Strength

Strength, Tensile
See Tensile Strength

Strength, Yield
See Yield Strength

Stress, Relieving
A heat treatment to reduce residual stresses followed by sufficiently slow cooling to minimize development of new residual stresses.

Stress, Residual
Those stresses setup up in a metal as a result of nonuniform plastic deformation or the unequal cooling of a casting.

Stress-Corrosion Cracking
Spontaneous failure of metals by cracking under combined conditions of corrosion and stress, either residual or applied.

Strike-Off
Operation of removing excess sand from top or core box or flask.
 
Stripper Pins
On certain molding machines, a series of pins (usually four in number) which support the rammed flask-half at the parting surface so that the mounted pattern may be drawn by lowering.

Stripping
Removing the pattern from the mold or core box from core.

Stripping Time
In oil-oxygen and nobake mixture, the moment when the core box may be satisfactorily drawn from the core, or pattern from the sand.

Structure (Cast Structure)
The size and disposition of the constituents of a metal as cast.

Styroform Pattern
Expendable pattern of foamed plastic, especially polystyrene, use in manufacturing casting by the Full_Mold process.

Sulfur
A nonmetallic element, melting point 444°C (831.2°F) occurring as an undesirable tramp (trace) element in most ferrous alloys.

Superalloy
An alloy developed for very high temperature use where relatively high stresses are encountered and where oxidation resistance is needed.

Surface Hardening
Conferring a superficial hardness to a steel while maintaining a relatively soft core.

Surface Texture
The roughness, waviness, lay or other characteristics of the surface of a part.

Swell
A casting defect consisting of an increase in metal section due to the displacement of sand by metal pressure.

System Sand
Foundry sand used in making molds and which eventually becomes the bulk of the sand used in the mechanical system or mechanized unit. See also Sand.

Temper
1) Reheating hardened, normalized or mechanically worked steel to a temperature below the critical range to soften it and improve impact strength.
2) The moisture content of a sand at which any certain physical test value is obtained, i.e., temper with respect to green compressive strength, permeability, retained compressive strength, etc.
3) To mix material with enough liquid to develop desired molding properties.
 
Temperature
Degree of warmth or coldness in relation to an arbitrary zero measured on one or more of accepted scales, as Centigrade, Fahrenheit, etc.

Temperature, Holding
1) Temperature above the critical phase transformation range at which castings are held as a part of the heat treatment cycle,
2) The temperature maintained when metal is held in a furnace, usually prior to pouring.

Temperature, Pouring
The temperature of the metal as it is poured into the mold.

Tempered Martensite
Martensite that has been heated to produce to BCC iron and a fine dispersion of iron carbide.

Tensile Strength
The maximum stress in uniaxial tension testing which a material will withstand prior to fracture. The ultimate tensile strength is calculated from the maximum load applied during the test divided by the original cross-sectional area.

Test Lug
An ear like projection cast as part of the casting and later removed for testing purposes.

Thermal Conductivity
The property of matter by which heat energy is transmitted through particles in contact. For engineering purposes, the amount of heat conducted through refractories is

usually given in Btu per hour for one square foot of area, for a temperature difference of one degree Fahrenheit, and for a thickness of one inch, Btu/hr·ft·F/in.

Thermal Contraction
The decrease in a linear dimension and volume of a material accompanying a change of temperature.
 
Thermal Expansion
The increase in a linear dimension and volume of a material accompanying a change of temperature.
 
Thermal Fatigue
Failure resulting from rapid cycles of alternate heating and cooling.

Thermal Shock
Stress developed by rapid and uneven heating of a material.

Thermal Spalling
Breaking up of refractory from stresses which arise during repeated heating and cooling.

Thermal Stability
Resistance of a material to drastic changes in temperature.

Thermocouple
A device for measuring temperatures by the use of two dissimilar metals in contact; the junction of these metals gives rise to a measurable electrical potential which varies with the temperature of the junction. Thermocouples are used to operate temperature indicators or heat controls.

Tie Bar, Rod
Bar or rod-shaped part of the casting added to prevent distortion caused by uneven contraction between separated members.

Titanium
A white metallic element, melting point 1660°C (3020°F), having a high strength-to-weight ratio; useful in aircraft parts.

Tolerance
The permissible deviation of a dimension from the nominal or desired value. Minimum clearance between mating parts.

Tool Steel
Any high-carbon or alloy steel used to make a cutting tool for machining metals and for metal-casting dies.
 
Toughness
The ability of the metal to absorb energy and to deform plastically during fracture. Toughness values obtained in testing depend upon the test temperature, the rate of loading, the size of the test specimen, as well as the presence of a notch and its acuity.

Tramp Element (Trace)
Contaminant in the components of a furnace charge, or in the molten metal or casting, whose presence is felt to be either unimportant or undesirable to the quality of the casting.

Transfer Ladle
A ladle that may be supported on a monorail or carried in a shank and used to transfer metal from the melting furnace to the holding furnace or from furnace to pouring ladles.

Transformation (Temperature) Range
The critical temperature at which a change in phase occurs. To distinguish between the critical points in heating and cooling those in heating are referred to as the Ac points (c for Chauffage or heating) and those in cooling, Ar. (r for Refroidissement)

Tungsten
Steel-gray, metallic element, mp 3380°C (6116°F) used for electric lamp filament, x-ray tube target, and as alloy element in high-speed steels.

Turntable
The base on which a centrifugal casting mold rests.

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.

Undercooling
See Supercooling

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

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.

Vacuum Degassing
The use of a vacuum technique to remove dissolved gases from molten alloys.

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

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.

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.

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.
 
Vicers Diamond Pyramid Hardness Tester
Patented indentation hardness machine. See Hardness
 
Virbrator
A device, operated by compressed air of electricity, for loosening and withdrawing patterns from a mold, or for vibrating a hopper or chute to promote the flow of material from the hopper or chute.

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.

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.

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 Pattern
1) 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,
2) wax molded around the parts to be welded by a termite welding process.

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.
 
Wild Steel
Steel which has not been completely deoxidized and reacts violently after casting due to liberation of gases of cooling.
 
X-Ray
Form of radiant energy with wavelength shorter than that of visible light and with the ability to penetrate materials that absorb or reflect ordinary light. X-rays are usually produced by bombarding a metallic target with electrons in a high vacuum. In nuclear reactions it is customary to refer to photons originating in the nucleus as gamma rays and to those originating in the extranuclear part of the atom as x-rays.

Yield
Comparison of casting weight to total weight of metal poured into mold.

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

Yield Strength
The stress at which a material exhibits a specified limiting permanent strain.
 
Zircon
The mineral zircon silicate, ZrSiO4, a very high melting point acid refractory material used as a molding material in steel foundries.

Zirconia
ZrO2 an acid refractory up to 2500°C (4532°F) having good thermal shock resistance and low electrical resistively.
 
Zirconium
Silvery-white, metallic element, mp 1860°C (3380°F), a powerful deoxidizer when added to molten steel.