The Glossary of Foundry and Casting
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.
Degree of resistance of a material to abrasion or wear.
A substance that hastens a reaction usually acting as a catalyst; as
used in sand additive resins.
Acceptable Quality Level (AQL)
A quality level established on a prearranged system of inspection
using samples selected at random.
Acid Brittleness (Picking brittleness)
Lack of ductility, induced in steel when it is pickled in dilute
acid to remove scale - commonly attributed to the absorption of
hydrogen. See Ductility.
Melting in a furnace with refractory material that has an acid
reaction. Material may be silica, sand, siliceous rock, or silica
A steel making method using an acid refractory-lined (usually
silica) furnace. Neither sulfur nor phosphorus is removed.
Steel melted in a furnace which has an acid bottom and lining, under
a predominantly siliceous slag.
Adapti Investment Casting Process
A lost wax process employing one of three methods; centrifugal,
vacuum or gravity-pouring casting. See Investment Casting.
Any material added to a charge of molten metal in bath or ladle to
bring alloy to specifications. A reagent added to the plating bath.
See Alloy, Ladle.
Any material added to molding sand for reasons other than bonding or
improvement of bond is considered an additive. Bonds can be of
varying types: carbonaceous (sea coal, pitch, fuel oil, graphite,
gilsonite); cellulose (wood flour, cereal hulls); fines (silica
flour, iron oxide, fly ash); cereals (corn flour, dextrine, sugar);
and chemical (boric acid, sulfur, ammonium compounds, diethylene
glycol). See Sea Coal.
Adeline Steelmaking Process
Method of producing a precision casting of steel or steel alloys
using aluminolthermic process and lost wax, followed by centrifugal
action. See Lost Wax Process.
ADI - Austempered Ductile Iron
A very high strength, high ductility, iron grade created through
heat treating. See Ductility.
AFS Fineness Number
Approximately the number of meshes per inch of a sieve that just
would pass the sand sample if its grains were uniform in size. In
other words, it is the average of the grains in the sand sample. See
American Foundrymen's Society.
A number of standard tests determined by American Foundrymen's
Society to evaluate molding and core sands. See Core Sand, Molding
Hardening by aging, usually after rapid cooling or cold working. See
A change in properties of metals and alloys which occurs slowly at
room temperature and will proceed rapidly at higher temperatures. A
change in the metal or alloy by which its structure recovers from an
unstable condition produced by quenching, quench aging, or by cold
working, strain aging. The change in structure consists. 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 Age Hardening, Precipitation Hardening.
Air Control Equipment
Any device used to regulate the volume, pressure, or weight of air.
A core or mold dried in air, without application of heat. See Core,
A form of reverberatory furnace for melting ferrous and nonferrous
metals and alloys. Flame from fuel burning at one end of the hearth
passes over the bath to the stack at the opposite end of the
furnace. Heat also is reflected from the roof and side walls.
Full hardening of a metal or alloy during cooling in air or other
gaseous medium from a temperature above its transformation range.
Air Injection Machine
An early type of die casting machine in which air pressure acting
directly on the surface of molten metal in a closed gooseneck forces
the metal into the die.
Accelerated cooling of alloy in an air stream from temperatures
above the Ac3 temperature. See Ac3.
Scale left on ferrous metal in processing, usually from heating in
presence of air.
The property of some materials to take a permanent set at normal air
temperature. Examples are gypsum slurry, investment molding
materials, core and mold washes, etc. See Core, Mold.
A cleaning operation, as cleaning sand from molds.
A steel containing sufficient alloy to fully harden during cooling
in air. Typically this term is restricted to steels being able to
harden in sections of about 2 inches (51 mm) or more.
Airless Blast Cleaning
A process whereby the abrasive material is applied to the object
being cleaned by centrifugal force generated by a rotating-vane-type
An electrical process for derusting steel, cast iron and other
ferrous alloys without using heat.
In a foundry, the clearance specified; difference in limiting sizes,
as minimum clearance or maximum interference between mating parts,
as computed arithmetically.
A substance having metallic properties and composed of two or more
chemical elements of which at least one is metal. A metallic
material formed by mixing two or more chemical elements. Usually
possess properties different from those of the components. As
examples, Brass is an alloy of copper and zinc and Cast Iron
contains iron, carbon and silicon. See Cast Iron.
Steel containing significant quantities of alloying elements other
than carbon and the commonly accepted amounts of manganese, silicon,
sulfur, and phosphorus.
Elements added to nonferrous and ferrous metals and alloys to
changer their characteristics and properties.
Body-centered cubic type of pure iron stable below 1,670°F (910°C).
A form or stage of martensite of somewhat arbitrary distinction,
probably representing the least developed and most distorted stage
in the transformation of austenite to martensite at ordinary
temperatures. See Martensite.
A shell molding and core-making method in which a thin resin-bonded
shell is baked with a less expensive, highly permeable material. See
Stress produced in a material by forces acting alternating in
Ames Portable Hardness Tester
The Rockwell penetration method of testing hardness of metals can be
made with this tester by applying pressure to the penetrator by
screw action. See Rockwell Hardness.
In spectrographic analysis, the particular spectral line used in
determining the concentration of an element.
A method of ultrasonic testing using shear waves introduced from the
surface of the material at approximately 45°F or °C.
The process of heating a metal and slowly cooling it, reducing the
brittleness and increasing the strength of the metal. See Bright
Annealing, Double Annealing.
Forming a conversion coating on a metal surface by electrolytic
oxidation with the work forming the anode. This process is most
frequently applied to aluminum.
Ant carburizing Compounds
Compounds applied to metallic surfaces to prevent surface
The net contraction of a casting dimension due to true metal
contraction, mold wall movement and restraint during solidification
and cooling. See Solidification.
A refinement of the precision casting process, using plastic
patterns produced in automatic injection machines. See Casting,
Argon Oxygen Decarburization (AOD)
A secondary refining process in which argon, oxygen and nitrogen are
injected into a molten bath of steel. The AOD process improves metal
cleanliness and thus gives superior mechanical properties.
Arnold's Fatigue Test
(Named after John Arnold), a test for fractures using 850 cyclic
stress reverses per minute, recording the number of cycles required
to produce fracture.
Equipment for removing dust from air.
An aging treatment above room temperature. See Aging, Age Hardening.
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 Heat Treatment.
Casting without subsequent heat treatment. See Casting, Heat
Assembling (Assembly) Line
Conveyor system where molds or cores are assembled. See Core, Mold.
Atomic Probe Field Ion Microscopy (APFIM )
An analytical technique in which atoms are ionized by an electric
field near a sharp specimen tip. The field then forces the ions to a
fluorescent screen which shows an enlarged image of the tip and
individual atoms are made visible.
Gases with which metal is in contact during melting or heat
treating. See Heat Treating.
Furnace atmosphere which is neither oxidizing nor reducing can be
made up of an inert gas e.g. argon, or the products of combustion.
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
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.
Atmospheric Riser (Williams)
Blind riser that employs atmospheric pressure to aid feeding.
Insertion of a small sand core into the riser provides a means for
ingress of air into the interior of the riser, and forces the metal
into the casting cavity. See Riser, Cavity, Mold or Die.
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. See Gamma Iron.
Any steel containing sufficient alloy to produce a stable austenitic
(gamma iron) crystalline structure at ambient temperatures. See
Usual reference is to an alloy steel or iron with structure at room
temperature that is normally composed essentially of austenite.
Back (Backing) Sand
Sand between the facing sand and the flask. See Facing Sand, Flask.
A reverse taper from the designed direction of draw from a pattern
or corebox; prevents removal of a pattern from a mold without damage
to the mold-tear ups. See Molds, Pattern.
Backing Board (Backing Plate)
A second bottom board where molds are opened.
The bonding agent used as an additive to mold or core sand to impart
strength or plasticity in a "green" or dry state. See Green Sand.
Plate or wall in a firebox or furnace to change direction of the
Connection between crane and hook and ladle. See Ladle.
In steel, an acicular aggregate of ferrite and carbide, resulting
from an isothermal transformation of austenite at a temperature
below the pearlitic range and above Ms. See Austenite.
Heat in an oven to a low controlled temperature to remove gases or
to harden a binder.
A core which has been heated through sufficient time and temperature
to produce the desired physical properties attainable from its
oxidizing or thermal-setting bindersas opposed to a green-sand core,
which is used in the moist state. See Binder, Core, Green Sand.
Property of a molded mass of sand heated at a temperature above 230ƒ
F until dry and cooled to room temperature, to permit passage of
gases through it; particularly those generated during pouring of
molten metal into a mold. See Mold.
Compressive, shear, tensile or transverse strength of a mold sand
mixture when baked at a temperature above 231ƒF (111ƒC) and then
cooled to room temperature. See Molding Sand.
A method of obtaining a high luster on small parts by rotating them
in a wooden-lined barrel with water, burnishing soap, and stainless
A loose steel frame placed inside a removable flask to reinforce the
sand at the parting line. See Flask, Parting Line.
Banking the Cupola
Method of keeping cupola hot and ready for immediate production of
hot iron after an unexpected shutdown of several hours. Procedure is
to drain all molten iron and slag from the cupola, place extra coke
on the top charge, and open one or two tuyeres to supply a small
natural draft to keep coke combustion going. See Coke, Cupola,
The decarburized layer just beneath the scale resulting from heating
steel in an oxidizing atmosphere.
Bar / Bars
Metal supports placed in a flask, usually the cope to reinforce
sand. See Cope, Flask.
Ribs of metal or wood placed across the flask to help support the
sand in the cope. See Cope.
A plate to which the pattern assemblies are attached and to which a
flask is subsequently attached to form the mold container.
Basic Bottom or Lining (Furnace)
Inner lining and bottom of a melting furnace composed of materials
having a basic reaction. Materials may be crushed burnt dolomite,
magnesite, magnesite brick, or basic slag. See Manganese Briquets.
Steel melted in a furnace with a basic bottom and lining under a
predominantly basic slag.
A cavity on top of the cope into which metal is poured before it
enters the sprue. See Cope, Sprue.
Amount or quantity of core or mold sand or other material prepared
at one time.
Oven use to bake a number of cores at one time.
Molten metal pool on the hearth of a furnace in a ladle or furnace.
A wooden bar or strip fastened to bottom or follow board for
rigidity or to prevent distortion during ramming of the mold. See
Designating or conforming to either of the scales used by the French
chemist Antoine Baume in the gradation of his hydrometers for
determining the specific gravity of liquids.
An ore of aluminum consisting of moderately pure hydrated alumna,
Half-round cavity in a mold, or half-round projection or molding on
a casting.A single deposit of weld metal produced by fusion.
Beam and Sling
Tackle used in conjunction with a crane for turning over the cope or
drag of a mold prior to assembly. See Cope, Drag.
The charge of iron placed on the coke bed in a cupola. See Coke Bed,
Coke placed in the cupola well to support the following iron and
Sinking a pattern down into the sand to the desired position and
ramming the sand around it. See Ramming.
Bedding A Core
Resting an irregularly shaped core on a bed of sand for drying.
Sinking a pattern in to the sand by excavating a "bed" in which the
pattern is placed for ramming up.
Method whereby drag may be rammed in the pit or flask without
necessity of rolling over. Process used in production of heavy
castings. See Drag, Ramming, Pit, Flask.
Coke which is produced in hemispherical ovens about 12 feet in
diameter and charged through the top to form a layer of coal 18 to
24 inches deep. Coke is ignited and air for partial combustion is
supplied over the top by doors around the bottom of the ovens. Air
burns volatile matter released by coke and during the later stages
of carbonization burns some 5% to 8% of the coke. See Coke.
A device operated with both hands, to produce a current of air. Some
bellows are mechanically operated.
Frame support on which small molds are made.
Man who makes small molds on a molder's bench. See Molding Bench.
A short rammer used by a bench molder. See Bench Molder.
A small core-blowing machine, utilizing a removable sand magazine
and blow heat.
Upper limit of normal stress of a beam at which fracture or
excessive plastic deformation occurs.
A widely distributed, peculiar type of clay which is considered to
be the result of devitrification and chemical alteration of the
glassy particles of volcanic ash or tuff. Used in a foundry to bond
A theorem which states that in a stream flowing without friction,
the total energy in a given amount of the fluid is the same at any
point in its path of flow.
Method of making steel by blowing air through molten pig or
carbon-bearing iron contained in a suitable vessel which causes
rapid oxidation of silicon, carbon, etc.
Casting, usually centrifugal, made of two different metals, fused
An alloy of two metals.
The bonding agent is a material used as an additive to mold or core
sand to impart strength or plasticity in a "green" or dry state. May
be cereal, oil, clay, resin, pitch, etc. See Green Sand.
Binder, Plastic (Resin)
Synthetic resin material used to hold grains of sand together in
molds or cores; may be phenol formaldehyde or urea formaldehyde
thermosetting types. See Cores, Molds.
American type of malleable iron. The normal fracture shows a velvety
black appearance having a mouse-gray rim. See Malleable Iron.
A natural form of graphite used for sleeking green sand molds, or
applied in a water suspension to skin dried molds. Graphite for
facing molds and cores. See Cores, Green Sand.
A form of casting defect related to an improper coating rather than
to the sand.
American type of malleable iron. The normal fracture has a medium
gray outer rim and a very black interior. See Malleable Iron.
Carbonaceous material for coating mold or core surfaces.
Carbonaceous materials such as plumbago, graphite or powdered coke
usually mixed with a binder and frequently carried in suspension in
water or other liquid; used as thin facing applied to surfaces of
molds or cores to improved casting finish. See Plumbago.
Irregular-shaped surface cavities in a casting containing
carbonaceous matter. Caused by spilling off of the blacking from the
A casting defect formed by blacking flaking off due to sand
expansion and being retained in or on the surface of the metal.
Air driven into the cupola or furnace for combustion of fuel.
Removal of sand or oxide scale from castings by the impinging action
of sand, metal shot, or grit projected under air, water, or
Closed-top-shaft furnace for producing pig iron from iron ore.
Sliding plate in the cupola blast pipe to regulate the flow of air.
Instrument indicates the volume or pressure, or both, of air passing
through the blast pipe.
Pressure of air in blast pipe or wind belt of the cupola, depending
on the location of indicating instrument. Usually given in ounces of
Blasting (Blast Cleaning)
A process for cleaning or finishing metal objects by use of an air
blast or centrifugal wheel that throws abrasive particles against
the surface of the work pieces. Small, irregular particles of steel
or iron are used as the abrasive in grit blasting, and steel or iron
balls in shot blasting. See Blast Cleaning.
Bleed (Bleeder, Bleeding)
Molten metal oozing out of casting stripped or removed from the mold
before solidification. See Solidification.
A defect wherein a casting lacks completeness due to molten metal
draining or leaking out of some part of the mold cavity after
pouring has stopped.
Blended Molding Sands
Naturally bonded molding sands which have been mixed or modified by
the supplier to produce desirable properties. See Molding Sands.
Mixture of sands of different grain sizes, clay content, etc., to
produce one possessing characteristics more suitable for foundry
A riser not opened to the atmosphere or does not reach to the
exterior of the mold. See Riser.
A defect on the surface of a casting appearing as a shallow blow
with a thin film of metal over it. In die-casting, it is a surface
bubble or eruption caused by expansion of gas (usually as a result
of heating) trapped within the die-casting or beneath the plating on
the die-casting. See Blow, Die-Casting (noun).
Adding ferrosilicon or other deoxidizing agent to a refined heat to
stop all oxidizing reactions.
Blocking the Heat
Stopping the carbon drop in production of steel by addition of
deoxidizers such as silicomanganese, spiegel, or ferrosilicon and
ferromanganese. See Spiegeleisen.
A casting defect due to trapping of gas in molten or partially
molten metal. See Blister.
A valve and nozzle attached to a compressed air line to blow loose
sand or dirt from a mold or pattern. Also to apply wet blacking.
A hole, or void, left in the casting caused by trapped air or gases.
The holes in the head plate or blow plate of a core-blowing machine
through which sand is blown from the reservoir into the core box.
The irregular shaped cavities with smooth walls produced in a
casting when gas is entrapped during mold filling. The gas sources
may be air, binder decomposition products or gases dissolved in the
molten steel. See Blow.
A small pipe or tube through which the breath is blown to remove
loose sand from small molds.
Plate on the bottom of the sand hopper on core or mold blower
machines which contains holes through which the sand is blown into
the core box or flask. The plate containing the core sand entrance
holes or blow holes used in open-face core boxes. See Core Box,
Machine or device for supplying air under pressure to the melting
Blower, Core Or Mold
A machine or device using compressed air to inject sand into a core
box or a flask. See Core Box, Flask.
Blowing Off A Mold
Cleaning a mold cavity with a stream of compressed air. See Cavity,
A small pipe or tube through which the breath is blown in removing
loose sand from small mold cavities.
The formation of a thin film of oxide on polished steel to improve
its appearance and protect its surface.
A riser or feeder, usually blind, to provide molten metal to the
casting during solidification, thereby preventing shrinkage
cavities. See Riser.
Bod (Bott) Stick
A stick or rod on which the bod is mounted to that it may be forced
into the tap hole. See Tap Hole.
A piece of clay or other material to stop the flow of metal from the
tap hole. See Tap Hole.
The main core.
Agitation of a bath of metal by using steam or gas beneath its
surface. May be deliberately induced by the addition of oxidizing
material to a bath containing excess carbon. In the later case it is
called a carbon boil and CO or CO2 are liberated.
(a) A bonding substance or bonding agents - any material other than
water, which, when added to foundry sands, imparts bond strength.
The overlapping of brick so as to give both longitudinal and
transverse strength. (b) Cohesive material in sand. See Foundry
Any clay suitable for use as a bonding material in molding sand. See
a property of foundry sand that offers resistance of foundry sand to
deformation. See Foundry Sand.
Bonding Clay (Bonderise)
Any clay suitable for use as a bonding material.
Method of assembling or bringing together two halves of a core in a
manner similar to closing a book. See Core.
An inhibitor used in facing sand for magnesium-base and
aluminum-base alloys high in magnesium to prevent reaction with
moisture in the sand. See Facing Sand.
A machining method using single point tools on internal surfaces of
Metal in chip form resulting from machining operations.
One of the periodic chart elements. Its chemical symbol is B and its
atomic weight is 10.82. In the form of borax and boric oxide, it is
used as a flux in nonferrous metallurgy, and in the form of an alloy
with other elements, as an addition to ferrous alloys. See Alloy,
A product used for degasification of aluminum alloys.
Sloping of the cupola lining to form a smaller diameter just above
the tuyeres. See Cupola, Tuyeres.
A projection of circular cross-section on a casting, usually
intended for drilling and tapping for attaching parts. See Casting.
A projection of circular cross-section on a casting. Usually
intended for drilling and tapping for attaching parts. See Casting.
The board that the mold rests on that supports the mold.
The doors that are underneath the cupola. See Cupola.
Bottom Pour Ladle
Ladle in which metal, usually steel, flows through a nozzle in the
bottom. See Ladle, Bottom Pouring.
Bottom Pour Mold
A mold that is gated at the bottom.
Bottom Running Or Pouring
Filling of the mold cavity from the bottom by means of gates from
the runner. See Gate, Runner, Mold Cavity.
Layer of molding sand rammed into place on the doors at the bottom
of a cupola.
Strengthening strip, rib, or projection on a casting; usually used
to prevent hot tearing. See Cracking Strip.
Part of a core assembly.
Two or more gates leading into the casting cavity. See Cavity.
Copper-base alloy with zinc as the major alloying element. See
Joining metals and alloys by fusion of nonferrous alloys with
melting points above 800ƒ F, but lower than those of the materials
An intentionally weak ring within mass of a ring shell mold to be
broken by force of casting shrinkage. Prevents hot tear stress. See
A thinner section of a gate or riser to facilitate and ensure clean
breaking-off during the cleaning process of casting.
Area surrounding the tap hole of a melting furnace. See Tap Hole.
Coke or coal screenings.
A tendency to fracture without appreciable deformation.
Material adhering to the cupola wall which slows or prevents descent
of the stock charges. See Cupola.
A process carried out usually in a controlled furnace atmosphere, so
surface does not oxidize, remaining bright. See Annealing.
The value of hardness of a metal on an arbitrary scale representing
kg/mm2 determined by measuring the diameter of the impression made
by a ball of given diameter applied under a known load. Values are
expressed in Brinell Hardness Numbers, BHN. See BHN.
Brinell Hardness Number (BHN)
A measure of how hard a material is. The higher the hardness number,
the harder the material. It is the most appropriate measurement
scale for measuring hardness in iron castings.
Compact cylindrical or other shaped blocks formed of finely divided
materials by incorporation of a binder, by pressure, or both.
Materials may be ferroalloys, metal borings or chips, silicon
Fracture with little or no plastic deformation.
Smoothing machined holes or outside surfaces of castings by drawing
pushing on or more broaches (special cutting tools) through the
roughed out hole.
A copper-base alloy, using tin as the major alloying element. See
Bulging of a large flat face of a casting; in investment casting,
caused by dip coat peeling from the pattern. Defect on a casting
surface, appearing as an indention resulting from an expansion scab.
An indentation in a casting, resulting from expansion of the sand,
may be termed the start of an expansion defect.
A pattern plate of suitable material with the cope pattern mounted
on or attached to one side with the drag on the other. See
Rubber ball with a small piece of sponge inserted in the hole.
The ratio of the weight of a material to its over-all volume
(including any inherent porosity).
Machine for ramming sand in a flask by repeated jarring or jolting
Term used to designate the metal charge for a melting furnace. It is
also used in cost accounting to indicate certain additional charges
to be included in assessing costs in the different areas.
See Penetration, Metal.
The process of cutting metal by a stream of fuel and oxygen. To
permanently damage a metal or alloy by heating to cause either
incipient melting or intergranular oxidation.
Sand in which the binder or bond has been removed or impaired by
contact with molten metal.
A misnomer usually indicating metal penetration into sand resulting
in a mixture of sand and metal adhering to the surface of a casting.
Sand adhering to the surface of the casting which is extremely
difficult to remove. This condition may be due to soft molds, poor
sand compaction, insufficient mould coating (graphite) paint, or
high pouring temperature.
A device which mixes fuel and air intimately to provide perfect
combustion when the mixture is burned. Types include acetylene, oil,
gas, powdered coal, stoker, etc.
A misnomer usually indicating metal penetration into molding and
core sand resulting in a mixture of metal and sand on a casting
usually due to the metal penetrating into the sand. See Core Sand,
Developing a smooth finish on a metal by tumbling or rubbing with a
polished hand tool.
Usually refers to removal of the disposable wax or plastic pattern
in the investment-molding process by heating the mold gradually to a
sufficiently high temperature to consume any carbonaceous residues.
In shell molding, resin burned out too soon. See Shell Molding.
A sleeve, metallic or nonmetallic, usually removable or replaceable,
which is placed in a body to resist wear, erosion, etc.
Operation performed at times to supplement ramming by jolting,
either hand or air rammer. See Ramming.
The flat end of the molder's rammer. See Ramming.