Glossary of Foundry Terms

  • Alloy
  • The combination of two or more chemical elements, of which at least one is metal. Usually possesses properties different from those of the components, i.e., Cast Iron contains iron, carbon and silicon.
 
  • Annealing
  • A process involving heating and slow cooling applied in order to alter mechanical or physical properties, particularly hardness-softening process.
 
  • Backdraft
  • 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.
 
  • Bars
  • Metal supports placed in a flask, usually the cope to reinforce sand.
 
  • Bath
  • Molten metal pool in a ladle or furnace.
 
  • BHN
  • Brinnell Hardness Number
 
  • Blasting
  • A process for cleaning or finishing metal objects by the high velocity impingement of hard metal short or grit against the surface of the object.
 
  • Blind Riser
  • A riser not opened to the atmosphere -- see riser
 
  • Blower-core
  • A machine using air-pressure to fill a corebox with sand.
 
  • Boss
  • A projection of circular cross-section on a casting, usually intended for drilling and tapping for attaching parts.
 
  • Brinell Hardness
  • The value of hardness of a metal on an arbitrary scale representing kg/mm2.
 
  • Burn-in/Burn-on
  • A misnomer usually indicating metal penetration into molding and core sand resulting in a mixture of metal and sand on a casting.
 
  • Cast Iron
  • Term used to describe a series of ferrous alloys containing over 1.74% of carbon.
 
  • Casting
  • Metal object obtained by pouring molten metal into a mold; also the act of pouring metal.
 
  • Chaplet
  • Metal support or spacer used in molds to help hold cores in proper position.
 
  • Charge
  • Material introduced into a furnace for melting.
 
  • Chill
  • Rapid cooling of thin section; causes a very hard and brittle condition; detrimental to machining.
 
  • Choke
  • Restriction in the gating system that controls the flow rate of metal into the mold cavity.
 
  • Coke
  • Fuel used in a cupola to melt charge materials. Source of some carbon found in iron.
 
  • Cope
  • Upper or topmost section of a mold, flask or pattern.
 
  • Core
  • Shaped body of sand which forms interior of casting and also selected external features.
 
  • Core Box
  • Wood, metal or plastic box, the cavity of which has the shape of the desired core which is to be made therein.
 
  • Core Print
  • Projections on a pattern that form and locate cores in a mold. Also, projection on core or area in mold for same purpose.
 
  • Core Rod
  • Steel rods imbedded in a core used to reinforce the core and strengthen it.
 
  • Crucible
  • Refractory vessel or pot, varying in size, for melting metal.
 
  • Cupola
  • Vertical shaft furnace lined with refractories used to produce cast iron by high temperature melting of metallic and mineral charge materials.
 
  • Die Casting
  • Forcing molten metal into permanent molds (dies). (also pressure casting)
 
  • Draft
  • The taper on vertical surfaces of a pattern which allows easy withdrawal of the pattern from a compacted sand mixture.
 
  • Drag
  • Lower or bottom section of a mold, pattern or flask.
 
  • Draw
  • To remove a pattern from a mold.
 
  • Drier-core
  • Plates for supporting odd shaped cores during baking.
 
  • Dross
  • Metal oxides and other scum on the surface of molten metal (mostly a non-ferrous term).
 
  • Dry Sand
  • Sand mixture that is baked to produce strong molds that are moisture free.
 
  • Ductile Iron
  • Also called Nodular Iron. Iron in which carbon is in the form of spherical nodules.
 
  • Feed Material
  • The volume of molten metal from which a casting feeds as it shrinks (contracts) during solidification.
 
  • Fin
  • A thin projection of metal from the casting, formed as a result of imperfect mold or core joints.
 
  • Flask
  • Molding box into which molding sand is placed against the pattern while the box surrounds the pattern; usually consists of a top and bottom (cope and drag).
 
  • Flat-back
  • Pattern with a flat surface at the joint of the mold. It lies wholly within the drag or cope, and this joint of the mold is a plane surface.
 
  • Flat/Knife Gate
  • Wide gate with narrow opening into the mold. It is used to pour thin, flat castings.
 
  • Flow-off
  • Large vent, usually located at the high point of a mold cavity. In addition to letting air and mold gases escape during a pour, the flow-off fills with metal and is allowed to run or flow during the final stage of pouring.
 
  • Fluidity
  • The ability of molten metal to flow easily.
 
  • Founding
  • The sciences of melting and casting of metals into useful objects that serve the needs of industry. It is better known as metal casting.
 
  • Gagger
  • Metal piece of irregular shape (usually an L shape) used to reinforce and support sand in deep pockets of molds. There are two types; straight or hooked (cast or steel rods).
 
  • Gate
  • That portion of a gating system where molten metal enters the mold cavity; also called an ingate.
 
  • Gating System
  • The complete assembly of sprues, runners and gates in the mold.
 
  • Green Sand
  • Tempered, i.e., moistened, molding sand.
 
  • Guide Pin
  • The pin on a flask used to locate the cope in the proper place on the drag; also used to locate cheeks.
 
  • Hardness/Brinell
  • Relative term referring to the resistance of a metal to plastic deformation from a given standard load applied on a standard penetration head.
 
  • Head
  • The pressure exerted by a fluid, as a head of molten metal.
 
  • Heat
  • An individual batch of molten metal.
 
  • Heel
  • Metal left in a ladle after pouring, or in a furnace after or between tapping.
 
  • Holding Furnace
  • A vessel to hold, and keep hot, certain amounts of molten metal.
 
  • Ingot
  • Casting to be later forged or hot worked. Also, a form used for convenient handling of cast iron, aluminum, and other commercial metals. i.e., Pigs
 
  • Inoculant
  • Materials, which when added to molten metal, modify the structure and thereby change the physical and mechanical properties.
 
  • Investment Casting
  • Process where patterns are removed by a melting or burning our process. i.e., Lost Wax Process
 
  • Jolt
  • To raise the flask filled with sand and allow it to drop, thereby compacting the sand against the pattern.
 
  • Knock-off Riser
  • Riser with a small attachment and can be knocked off with a hammer.
 
  • Ladle
  • Metal barrel-like receptacles lined with a refractory material used to transport or pour molten metal.
 
  • Lap-gate
  • When the connection point of ingate to casting overlaps onto the cope surface. i.e., Kiss-gate
 
  • Loose-pieces
  • Part of a core box or pattern which remains embedded in the core or mold and is removed after lifting off the core box or drawing the pattern. Backdraft is avoided by this means.
 
  • Malleable Iron
  • Annealed white iron.
 
  • Mold
  • The complete "box of sand" with the cavity inside and the gating system ready to accept molten metal.
 
  • Mold Wash
  • Refractory emulsion coating used to coat cavity walls; guards against penetration of metal into sand walls.
 
  • Muller
  • Type of sand mixing machine.
 
  • Mulling
  • The thorough mixing of sand, water and binding ingredients to form tempered ready-to-use molding or core sand.
 
  • Natural Sand
  • Mixture of sand and clay that can be used for molding; found in nature.
 
  • Nodular Iron
  • See Ductile Iron.
 
  • Oil Sand Core
  • Core in which sand mass is bound by an oil-based binder.
 
  • Open Riser
  • Riser whose top is open to the atmosphere through the top of the mold.
 
  • Padding
  • The process of adding extra material to a cross-section of a casting wall, usually extending from a riser to ensure adequate feed to a localized area where sharing would occur if the added material were not present. It must be machined off of casting.
 
  • Parting Line
  • The joint where mold separates to permit removal of pattern; separates cope and drag.
 
  • Pattern
  • Form of wood, metal or plastic around which molding material is packed to produce a mold cavity for casting metals. Corresponds to shape desired for casting.
 
  • Peel
  • Free removal of burnt molding sand from casting.
 
  • Permanent Mold
  • Casting, using gravitational force, into molds of metal or come Casting other material of permanence.
 
  • Pig Iron
  • See Ingot.
 
  • Plumbago
  • Powdered graphite.
 
  • Pocket
  • A body of sand surrounded on all but one side by molten metal.
 
  • Pouring Basin, Cup
  • Located on top of sprue or downgate. That portion of the gating
 
  • Print
  • Part of the core used to locate and support-part of a pattern to form area in mold for same purpose; part of mold and part in core box for the same purpose.
 
  • Printing Back
  • To dust cavity with Plumbago and reprint pattern. It smoothes the cavity surface by filling voids.
 
  • Ram
  • Process of packing sand in a mold using a hand, pneumatic or mechanized ramming device.
 
  • Returns
  • Metal in the form of gates, sprues, risers or defective castings which are put back into the melting cycle.
 
  • Riser
  • Reservoir of molten metal to supply a contacting, cooling casting with make-up metal; used to prevent internal or external voids due to shrinkage.
 
  • Riser Contact
  • The connecting passage between a riser and a casting.
 
  • Runner
  • Portion of a gating system which carries molten metal from the sprue to the gates, i.e., the metal distribution system.
 
  • Runner Box
  • system into which molten metal is introduced.
 
  • Runner Extension
  • Part of a runner which extends beyond the farthest ingate as a blind end. It acts as a dirt trap and is sometimes vented.
 
  • Scrap
  • Metal to be re-melted; castings that have to be re-melted.
 
  • Seacoal
  • Term applied to finely ground coal which is mixed with sands for foundry uses.
 
  • Shakeout
  • Process of removing sufficiently cooled castings from a mold.
 
  • Sharp Sand
  • Sand free from binders, i.e., new, clean sand of angular shape.
 
  • Shell Process
  • Molds and cores having shell-like structures using thermo-setting resin as binders, heated patterns, and coreboxes.
 
  • Shot
  • Metallic abrasive commonly used for cleaning casting surfaces.
 
  • Shrinkage
  • Difference in volume between liquid metal and solid metal in a given cavity.
 
  • Slag
  • Non-metallic impurities found floating atop a ferrous metal bath.
 
  • Slag Trap
  • An enlargement, dam or protrusion in the gating or runner system in a mold for the purpose of preventing molten slag particles from entering the mold cavity.
 
  • Sprue or Down-gate
  • The vertical channel connecting the pouring basin with the runner system and terminates in the sprue well at the bottom.
 
  • Steel
  • An alloy of iron and carbon, containing no more than 1.74% carbon.
 
  • Stool
  • Device used on molding machine to hold pattern plate or refractory block used to support a crucible in a crucible furnace.
 
  • Stress Raisers
  • Factors such as sharp changes in contour or surface defects which concentrate stresses locally.
 
  • Strike-off
  • Operation of removing excess sand from top of core box or flask. Metal bar used for same purpose.
 
  • Stripping
  • Removing the pattern from the mold or core from core box.
 
  • Synthetic Sans
  • Synthetic mixture of silica sand and exact proportions of binders and additives instead of using natural sands.
 
  • Tear-Ups
  • Defect caused by backdraft, damaged pattern or uneven drawing of pattern.
 
  • Telltale
  • Any distinguishing mark, projection, groove, etc. on a pattern, core box, mold or core which acts as a guide mark for assembling matching parts.
 
  • Tucking
  • Manual pressing of sand under bars, in pockets and around gaggers where ramming alone fails to give desired density.
 
  • Ultrasonic
  • Cleaning process that utilizes high-frequency sound waves to clean and remove contaminants.
 
  • Upset
  • An addition to any flask part to increase height or depth.
 
  • Vent
  • Small opening or passage through which gasses can escape during the pouring of a mold.
 
  • Washburn Core
  • Thin core which constricts the riser at the point of attachment to (Neck-Down Core) the casting.
 
  • Washes
  • Refractory coating applied to molds and cores to provide protection against penetration from molten metal.
 
  • Yield
  • Comparison of finished casting weight verses total weight of metal poured in a mold.