Glossary and Terms of the Foundry Industry

Steel Founders' Society of America

Glossary of Foundry Terms - S

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SAE Specifications: A set of materials specification issued by the Society of Automotive Engineers, Inc.
Sag: A decrease in metal section in casting due to sagging of the cope or core.
Salamander: 1) A heating device, usually of drum shape, in which fuel is burned in the open air by natural draft, 2) iron which has collected in the bottom of a blast furnace during a blow.
Salt Bath: A bath of molten salts used for heating steels, for hardening or tempering.
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. Most foundry sands are made up principally of the mineral quartz (silica). Reason for this is that sand is plentiful, refractory, and cheap; miscellaneous sands include zircon, olivine, chromite, CaCO3, black sand (lava grains), titanium minerals and others.
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.
Sand Tempering: Dampening and cutting over or otherwise mixing sand to produce uniform distribution of moisture, and allowing time for migration of water molecules.
Sand Wall: Temporary independent wall separated from a slag pocket wall; facilitates slag removal and protects permanent wall.
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.
Scanning Electron Microscope (SEM): An instrument used for obtaining microstructure images using an electron beam. The micrographs obtained give depth perception of the metal being observed.
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 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.
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.
Scrubbers: See Wet Scrubbers
Sealed Source: Any radioactive material that is encased in and is to be used in a container in a manner intended to prevent leakage of the radioactive material.
Seam: A surface defect on a casting related to but of lesser degree than a Cold Shut; a ridge on the surface of a casting caused by a crack in the mold face.
Segregation: A concentration of alloying elements at specific regions, usually as a result of the primary crystallization of one phase with the subsequent concentration of other elements in the remaining liquid.
Selenium: A metalloid melting 220°C (428°F) added to stainless steel to improve machinability.
Separator: A mechanical unit which separates or grades ground materials into constituent parts, used in the foundry to remove fines from the system sand and dust from the air.
SFSA: See Steel Founders' Society
Shakeout: 1) The operation of removing castings from the mold 2) a mechanical unit for separating the molding materials from the solidified metal casting.
Shank: The handle attached to a ladle.
Shaw (Osborn-Shaw) Process: A precision casting technique in ceramic molds which do not require wax or plastic investment.
Shear: A type of deformation in which parallel planes in the metal crystals slide so as to retain their parallel relation.
Shear Modulus (G): In a torsion test, the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range. Units are Pa or psi.
Shear Strain: Elastic displacement produced by pure shear loading.
Shear Strength: Maximum shear stress a material is capable of withstanding without failure.
Shear Stress: Load per unit area parallel to the plane of contact.
Shell Molding: A process for forming a mold from resin-bonded sand mixtures brought in contact with pre-heated (300-500°F) metal patterns, resulting in a firm shell with a cavity corresponding to the outline of the pattern.
Shift: A casting defect caused by mismatch of cope and drag or of cores and mold.
Shortness (Hot): Brittleness in a metal at an elevated temperature.
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 point to normal temperature, 4) the decrease in dimension in clays occurring when drying at 100°C (212°F) and even more so on firing, 5) reduction in dimension of refractory material during heating.
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)
Simultaneous Engineering: Refers to the process where user/designer and producer interact to reduce lead time and improve the efficiency of a part. This process is faster and more efficient than the traditional sequential process of design and manufacture.
Sintering: The bonding of adjacent surfaces of particles of a mass of powder or a compact by heating to a suitable temperature and cooling.
Sintering Point: That temperature at which the molding material begins to adhere to the casting, or in a test when the sand coheres to a platinum ribbon under controlled conditions. Also, the temperature at which sand grains begin to adhere to one another.
Shewed Tolerances: Tolerances which are non-symmetrically distributed about the design parameter.
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.
Skin-Drying: Drying the surface of the mold by direct application of heat.
SLA: See Stereolithography Apparatus
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.
Slip Casting: In ceramics, a pouring slip, a water suspension of finely ground clay, into a plaster of paris mold. After it hardens it is dried and fired.
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 cracks of a core, etc.
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.
Smoke: A type of emission resulting from incomplete combustion and consisting predominantly of small gas borne particles of combustible material present in sufficient quantity to be observable independently of the presence of other solids in the gas stream.
Soaking: Prolonged heating of a metal, furnace or ladle at a selected temperature.
Society of Automotive Engineers, Inc.: See SAE
Sodium Silicate: See Water Glass
Softening: A process used to soften metals through annealing or tempering.
Soldering: 1) Joining metals by fusion of alloys that have relatively low melting points - most commonly, lead-based or tin-based alloys, which are the soft solders. Hard solders are alloys that have sliver, copper, or nickel bases, and use of these alloys with melting points higher than 800°F (426.7°C) is generally termed brazing, 2) the sticking or adhering of molten metal to portions of a die.
Sold: That material which has a tendency to resist any attempt to change its size or shape.
Solidification: The physical process of change from a liquid to a solid state. See Casting Analysis of Solidification (13kB)
Solidification, Shrinkage: The decrease in size accompanying the freezing of a molten metal.
Sonic Testing: Using sound waves above audible frequency via a supersonic reflectoscope to measure time sound waves take returning from opposite sides of casting. Defects return the waves in more or less time.
Sorbite: Tempered martensite that has a micro-structure of distinctly granular appearance. Further tempering causes the appearance of clearly resolvable carbide particles (spheroidite).
SPAL Process: See Surface Protection Air Liquide
Spalling: Buckling or flaking off of the surface material.
Specific Gravity: A numerical value representing the weight of a given substance as compared with the weight of an equal volume of water at 39°F (3.9°C), for which the specific gravity is taken as 1,000 kg/m3.
See also Density
Specific Heat: Equivalent to thermal capacity, or the quantity of heat required to produce a unit change in the temperature of a unit mass.
Specific Volume: Volume of one gram of a substance at a specific temperature, usually 68°F (20°C).
Spheroidite: A cementite aggregate of globular carbide and ferrite.
Spheroidized Cementite (Divorced Pearlite): The globular condition of iron carbide after a spheroidizing treatment.
Spiegeleisen (Spiegel): Alloy of iron and manganese used in basic and acid open hearth steelmaking practice. A high manganese pig iron, usually containing 15% or 20 Mn and 4.5-6.5% C.
Spiral Test: A method of interpreting the fluidity of an alloy by pouring molten metal into a mold with a long narrow channel. The length of such casting, under standardized conditions, is taken as the fluidity index of that alloy.
Splash Core: A core of tile placed in a mold to prevent erosion of the mold at places where metal impinges with more than normal force. Splash cores are commonly used at the bottom of large rammed pouring basins, at the bottom of long downsprues, or at the ingates of large molds.
Spongy Casting: A casting in which the metal is porous and dendritic.
Spout: A trough through which the metal flows from the furnace to the ladle.
Spary Quenching: After solution heat treating, a mode of quenching in which a spray of water is directed upon material just removed from the furnace.
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.
Standard Deviation: A statistical quantity used to describe the variation of a measurable attribute about some average value.
Standard Pattern: A pattern of high-grade material and workmanship in daily use or at frequent intervals. A pattern used as a master to make or check production patterns.
Standard Samples: A sample of know composition used to calibrate an instrument or method of analysis.
Standard Shapes: Refractory units stocked by manufacturers or made from stock molds.
Stave Construction: Attaching staves to polygonshaped heads in the building of cylindrical bodies; also, standard method used in making semicircular core boxes.
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.
Steels, SAE: Common designation for the standard grades of steel approved by the Society of Automotive Engineers.
Stellite: Proprietary name of a group of complex alloys retaining their hardness strength and resistance to oxidation at high temperatures; contains W, Co, Cr and C.
Steeped Construction: In patternmaking, the courses of material that when fastened together resemble steps.
Stereolithography Apparatus (SLA): Equipment used for computerized building of three-dimensional models and patterns. Enables the data representation of a CAD solid model to be directly converted into a plastic model of a casting.
Sticker: A lump on the surface of a casting caused by a portion of the mold face sticking to the pattern. Also, a forming tool used in molding.
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.
Stool: Support for a green sand core on a molding machine.
Stool Plate: Plate on a mold machine on which stools are mounted.
Stooling: Supporting green sand cores in machine molding while pattern is being withdrawn.
Stopper Head: A refractory shape at the end of a stopper rod, usually clay and graphite, seated in a ladle's nozzle.
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.
Strained Casting: A phrase used to describe the result when molten metal is poured into the mold at too fast a rate or under too great metallstatic pressure, causing the cope to rise slightly from the drag and resulting in an oversize casting.
Strainer Core: See Core Strainer
Streamline Flow: Steady flow of liquid without turbulence. Generally, not experienced in metalcasting.
Strength, Baked: Compressive, shear, tensile, or transverse strength of a molded sand mixture when baked at a temperature above 230°F (110°C) and then cooled to room temperature.
Strength, Compressive: See Compressive Strength
Strength, Impact: See Impact Strength
Strenght, Retained: Compressive, shear, tensile, or transverse strength attained by a sand mixture after being subjected to a cycle or cycles of heating and cooling which approximate foundry practice.
Strength, Shear: See Shear Strength
Strength, Tensile: See Tensile Strength
Strength, Yield: See Yield Strength
Stress-Corrosion Cracking: Spontaneous failure of metals by cracking under combined conditions of corrosion and stress, either residual or applied.
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.
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.
Subcutaneous Blowhole: Blowholes at or near the surface of solidified metal, covered with a thin layer of metal. May also be called pinhole porosity.
Subzero Treatment: Refrigeration of steel to promote transformation of retained austenite.
Sulfur: A nonmetallic element, melting point 444°C (831.2°F) occurring as an undesirable tramp (trace) element in most ferrous alloys.
Sulfur Prints: A macrographic method of examining for the distribution of sulfide impurities, in which a sheet of wet acidified bromide paper is placed on the polished surface to be examined.
Superalloy: An alloy developed for very high temperature use where relatively high stresses are encountered and where oxidation resistance is needed.
Supercooling: Lowering the temperature of a molten metal below its liquidus during cooling.
Superduty Fireclay Brick: Having pce above 33 with less than 1.0 percent linear shrink in the 1599°C (2910°F) reheat test, and less than 4.0 percent loss in panel spalling test preheated at 1649°C (3000°F).
Superheat: Any increment of temperature above the melting point of a metal; sometimes construed to be any increment of temperature above normal casting temperatures introduced for the purpose of refining, alloying or improving fluidity.
Supersaturated: Metastable solution in which the dissolved material exceeds the amount the solvent can hold in normal equilibrium at the temperature and under the other conditions that prevail.
Supersonic Reflectoscope: An instrument for sending, receiving, and measuring sound waves over 20,000 cycles per second.
Supramor: An electromagnetic flaw detection ink for the rapid detection of subcutaneous and surface flaws in ferrous metals.
Surface Hardening: Conferring a superficial hardness to a steel while maintaining a relatively soft core.
Surface Protection Air Liquide (SPAL): The use of liquid argon, liquid nitrogen, or carbon dioxide snow to minimize the reaction of air and molten metal that normally occurs in an induction furnace. The liquid or snow is fed onto the surface of the molten metal where it vaporizes, displacing the air thus reducing slag and oxygen levels.
Surface Texture: The roughness, waviness, lay or other characteristics of the surface of a part.
Surfacing: Depositing a filer metal on a metal surface by any method to obtain certain desired properties or dimensions.
Swell: A casting defect consisting of an increase in metal section due to the displacement of sand by metal pressure.
Swing Frame Grinder: A device for grinding large castings where the work remains stationary. This grinder, too large to be hand lifted, is usually suspended from a hoist.
Synthetic Molding Sand: Any sand compounded from selected individual materials which, when mixed together, produce a mixture of the proper physical and mechanical properties from which to make foundry molds.
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