Glossary of Terms
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A
Alloy
A substance containing two or more chemical elements, at least one of which is metal. The substance usually has metallic properties and possesses qualities different from those of the individual components.
B
Bentonite
Clay that is used to hold green sand molds together. The two most common types are called Western and Southern.
Binders
Binders are added to mold materials in order to create a mold of sufficient hardness. Binders can be either organic or inorganic materials.
Bond
Bentonite plus Sea coal and minor additives premixed together. Bond is added to greensand systems, along with water to hold the molds together.
C
CAD
Computer Aided Design
CAM
Computer Aided Manufacturing
Captive Foundry
A foundry operation that is wholly incorporated into a larger manufacturing operation. A captive foundry only produces castings for the operation that it is a part of.
Casting
A process used to form solid metal shapes out of molten metal. The molten metal is poured into a cavity or a mold.
Chaplet
A consumable device that holds a core in place in the mold.
Charge
Metal and alloy materials that make up the composition of a melt.
Cope
The top half of a horizontally parted mold.
Core
The part of a mold used in the casting process that forms the internal shapes of a casting.
Core Wash
A material added to a core that creates a smoother surface on a casting than would otherwise be.
Crucible Furnace
A furnace that melts metals in a refractory crucible. The furnace is typically fueled with coke, oil, gas or electricity.
Cupola Furnace
The traditional furnace used for melting metal. The furnace is typically fueled with coke.
D
Direct-Arc Furnace
An electric arc furnace in which the metal being melted is one of the poles.
Draft
Taper on the vertical sides of a pattern or core box that permits the core or pattern to be removed without distorting or tearing of the sand.
Drag
The bottom half of a horizontally parted mold.
F
Ferrous Metal
An alloy that has iron as the predominant metal.
Flash
A thin section of metal formed at the mold, core, die joint or parting in a casting. Flash usually forms when the cope and drag do not match completely or when the core and the core print do not match.
Foundry, Captive
A foundry operation that is wholly incorporated into a larger manufacturing operation. A captive foundry only produces castings for the operation that it is a part of.
Foundry, Jobbing
A foundry that creates a wide variety of castings, in small quantities for a range of customers.
Furnace, Crucible
A furnace that melts metals in a refractory crucible. The furnace is typically fueled with coke, oil, gas or electricity.
Furnace, Cupola
The traditional furnace used for melting metal. The furnace is typically fueled with coke.
Furnace, Direct-Arc
An electric arc furnace in which the metal being melted is one of the poles.
Furnace, Induction
An alternating current melting furnace that uses the heat of electrical induction.
G
Gas Porosity
A condition in a casting that occurs when gas is trapped in molten metal or as a result of mold gasses that evolved when the casting was poured.
Gating Systems
The channel(s) that allow the molten metal to enter the mold cavity.
Green Sand
Moist sand that is bonded by a mixture that contains silica, bentonite clay, carbonaceous material, and water.
Gross Weight of Casting
The weight of the casting which includes the actual product plus the metal in the gating system as poured.
H
Hot Isostatic Pressing (HIP)
The process of using high hydrostatic pressure and high temperature to compress fine particles into coherent parts.
I
Impurity
An element that is allowed into a metal or alloy. Impurities slightly change the properties of the material in some circumstances and can completely damage it in others.
Inclusion
Nonmetallic materials that become part of a metal matrix usually through reoxidation, refractories, slag, and deoxidization products.
Induction Furnace
An alternating current melting furnace that uses the heat of electrical induction.
Investment Casting
A casting process that uses a wax or thermoplastic pattern and is surrounded in a refractory slurry to form a mold. Once the refractory slurry is dry, the wax or plastic is melted out and the mold is formed. Molten metal is then poured in to fill the area that was previously filled with wax.
J
Jobbing Foundry
A foundry that creates a wide variety of castings, in small quantities for a range of customers.
L
Ladle
The name for a variety of receptacles used to move and pour molten metal during the casting process.
Lining
The refractory layer of firebrick, clay, sand or other materials that coat the inside of a furnace or ladle.
Lost Foam Process
A casting process that uses foam to form the pattern. The foam is eventually melted out of the mold when the molten metal is poured in.
M
Metal Yield
The difference between the weight of a finished casting and the total weight of the metal poured.
Mold
The cavity that the molten metal is poured in to form the final shape. A mold usually consists of a top and bottom piece made of sand or ceramic material.
Mold Vent
A passageway in the cope mold that gas followed by molten iron exits during the pour.
Muller
A piece of equipment that sand, bond, and water are combined and kneaded together.
N
Net Weight of Casting
The final weight of a casting that is determined once all of the excess metal from the gating system has been removed.
Non-ferrous Metal
An alloy that does not have iron as the predominant metal.
O
Oxidation Losses
The loss of metal or alloy through the process of oxidation.
Oxidizing Atmosphere
Furnace atmosphere which gives off oxygen under certain conditions or where there is an excess of oxygen in the product of combustion, or the products of combustion are oxidizing to the metal being heated.
P
Parting
The surface of the cope and drag mold that touch each other.
Pattern
The wood, metal, foam or plastic replica of the final product to be made. Patterns usually include gating systems.
Pattern Draft
The taper allowed on the vertical faces of a pattern to enable removal of the mold or die.
Pattern Vent
A slotted plug in a pattern or pattern plate that allows air to flow through, but not much sand.
Pigging
Pouring molten metal back into lined containers so that it can be returned to the furnace.
Porous Plug
A piece of refractory (usually at the bottom of a ladle) that gas can pass through, but liquid metal can not. Gas that passed through a porous plug can be used to stir liquid metal.
R
Rapid Prototyping
The computerized equipment that builds a three-dimensional model of a casting from a CAD drawing.
Reducing Atmosphere
Furnace atmosphere which absorbs oxygen under suitable conditions or in which there is insufficient air to completely burn the fuel, or the product of combustion is reducing to the metal being heated.
S
Sand Casting
Producing metal castings out of sand molds.
Sand Reclamation
Processing used sand grains into usable forms so that they can be used in the casting process as a replacement for new sand.
Scab
A casting defect resulting from the expansion of sand during casting process.
Scrap
All non-product metal produced during the casting process.
Sea Coal
Coal that is added to green sand systems to aid in the separation of iron and sand at the shakeout.
Seiatsu
A molding process that uses air to aid in making a mold.
Shakeout
The separation of iron and sand.
Shell Molding
Bringing a resin-bonded sand mixture into contact with a pre-heated metal pattern to form a mold.
Shell Process
The process in which clay-free silica sand coated with a thermostatic resin or mixed with resin is placed on a heated metal pattern for a short period of time to form a partially hardened shell. The bulk of the sand mixture inside the resulting shell is removed for further use. The pattern and shell are heated further to harden or polymerize the resin-sand mix, and the shell is removed from the pattern. Frequently, shell cores are made using this process.
Shot Blasting
A process for cleaning castings that involves using a metal abrasive that is propelled by centrifugal or air force.
Shrink Hole
A cavity that forms in a metal part when there was not enough source metal fed into the mold during the casting process.
Shrinkage
The reduction in the volume of metal that occurs as it solidifies.
Slag
A film that forms on top of molten metal as a result of impurities. Slag is composed of non-metal elements.
Slag Inclusions
Imperfections of the surface of metal caused by slag (impurities in the molten mix).
Slurry
The watery mixture such as the gypsum mixture for plaster molding, the molding medium used for investment casting, core dips, and mold washes.
Sprue
The opening in the mold where the metal is first poured.
