D (Fordath) Process
Shell molding in which the shell is made by blowing sand into a box like heated structure so that a shell of controlled thickness is created. See Shell Molding.
The ability to absorb vibration. More accurately defined as the amount of work dissipated into heat by a unit volume of material during a completely reverse cycle of unit stress.
In layout and machining operations the reference plane from which dimensions are measured in the perpendicular direction.
In layout and machining operations the reference points on a datum plane from which dimensions are measured.
To coat or plaster the inside of a cupola at the melting zone or the inside of a ladle with a refractory mixture.
Filling of cracks in molds or cores by specially prepared pastes or coatings to prevent a mechanical penetration of metal into these cracks during pouring. Also, the final plastering or coating of the cupola or ladle after shrinkage has taken place during the drying period. Clay slurry or clay wash with various coating compounds are applied. See Clay Wash.
DC (Direct Chill) Casting
A continuous method of making ingots or billets or extrusion by pouring the metal into a short mold. Some times called semi-continuous casting.
Term applied to refractory materials obtained by calcimining at a temperature high enough to form a product inert to atmospheric moisture and carbon dioxide, and less apt to contract. See Refractory.
Dolonite burned at high temperature with additions of an agent, such as oxide of iron.
Pour from one vessel to another. Pour off molten metal without disturbing the sludge.
Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium, usually oxygen, that react with carbon.
Unit for measuring the ration amounts of acoustical power; one-tenth of a bel.
Macroetching; etching for examination at a low (less that 10X) magnification, in a reagent that attacks the metal to a much greater extent than normal for microscopic examination. Gross features may be developed; i.e., abnormal grain size, segregation, cracks, or grain flow.
Deep Red Filter
A gas filter in air pollution control, consisting of a loosely packed mat of fibrous materials; not practical where high grain loading are encountered.
A discontinuity in the product whose severity is judged unacceptable in accordance with the applicable product specification.
An AGS test using an instrument such as the Dietert Universal Sand-Strength Testing machine (with deformation accessory) to determine the amount in inches that the sand specimen is compressed before it ruptures.
A material employed for removing gases from molten metals and alloys.
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.
A flux for removing gas from the melt.
Degree of Ramming
Delay Screen (Skim gate (Erroneously), Skim Strainer)
A small piece of perforated light gage tinned sheet steel, or of copper, aluminum, and/or magnesium alloys, frequently placed in the pouring basin at the top of the downsprue. It delays the flow of metal long enough to allow the basin to fill before it melts to permit only clean metal from the bottom of the basin to enter the downsprue. Delay screens are also use elsewhere in the gating system.
An allotropic (polymorphic) form of iron, stable above 2550°F, crystallizing in the body-centered-cubic lattice.
A crystal of branched appearance, formed during solidification of alloys, the branching habit being controlled by specific crystallographic directions with the branching structure resembling a a fir tree.
Instrument utilizing the photoelectric principle to determine the degree of darkening of developed photographic film.
The mass per unit volume of a substance, usually expressed in grams per cubic centimeter or in pounds per cubic foot.
Density is used to denote the degree of darkening of photographic film. Logarithm of opacity of exposed and processed film. Opacity is the reciprocal of transmission; transmission is the ratio of transmitted to incident intensity.
Elimination of phosphorus from molten steel.
An inflammation of the skin, which may be caused by allergy to certain casting adjuncts, as resins; particularly in the shell process.
Remove the fire scale from the surface of casting. See Casting.
Design Base Line
The noise spectrum which is the goal of any particular noise reduction program.
Type of metal named, as steel, malleable, nonferrous, etc.
Hardening by the formation of hard microconstituents dispersed in a softer matrix. See Precipitation Hardening.
Removal of sulfur from the molten metal by addition of suitable compounds.
A material used to remove sulfur from molten metals and alloys. Also, a form of holding ladle or basin in which the molten metal and desulfurizing material are brought into contact. See Ladle.
Detroit Cup Test
A cupping test for sand, using a steel ball as plunger, the depth of cup being shown on a dial.
The temperature at which moist air will become saturated and condensation of water vapor will take place.
The process of melting out the expendable was pattern from an investment mold by the application of heat, usually at temperatures less than 250°F (121°C).
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.
Soluble gummy carbohydrate formed by the decomposition of starch by heat, acids, or enzymes; it is use din core compounds, mold compounds, mold washes, core pastes, and other compounds requiring high dry compressive strengths.
Corrosion of some copper-zinc alloys, involving loss of zinc and the formation of a spongy porous copper. See Alloy.
In microscopy, an indication of the amount of magnification. 1000 diameters = 1000 times original size.
Used to fireproof clothing of foundry workers.
Diaphragm Shell Molding Machine
An arrangement for applying a squeeze pressure with a high-temperature silicone rubber diaphragm.
A rocklike mineral consisting chiefly of diaspore (HAlO2) bonded by fire clay substance with an alumina content higher than 63%.
Dia-Tester (Wolpert Hardness Tester)
An instrument for examining the thermal resistance or the heat conducting power of objects.
Diatomaceous Earth (Infusorial Earth)
A hydrous of silica which is soft, light in weight and consists mainly of microscopic shells of diatoms or other marine organisms.
A metal block used in forming materials by casting, molding, stamping, threading, or extruding. A metal form used as a permanent mold for die casting or lost wax process. See Lost Wax Process.
The parts of a die stamp or press that hold the die and locate it for the punches.
(a) Forcing molten metal into permanent molds, dies. Die Casting is also called Pressure Casting. See Pressure Die Casting. (b) noun Casting resulting from die-casting process. (c) verb Pouring molten metal under pressure into metal molds.
Die Casting, Cold Chamber
Type of casting made in a die-casting machine in which the metal injection mechanism is not submerged in the molten metal.
Die Casting, Hot Chamber
Type of casting made in a die-casting machine in which the metal injection mechanism is submerged in the molten metal.
See Release Agent.
A removable liner or part of a die body or punch.
In stamping, the parts of the press that hold the die and locate it in proper relation to the punches.
Forming or machining a depressed pattern in a die.
Differential Heat Treatment
A heating process by which the temperature is varied within the object so that, after cooling, various parts may have different properties as desired. See Heat Treatment.
X-ray equipment, a portion of the condensing and focusing system that permits even distribution of energy. See X-Ray.
Movements of atoms within a solution. Net movement is usually from regions of high concentration to regions of low concentration to achieve homogeneity of the solution which may be a solid, gas, or liquid.
A patented flexible seal to prevent blow-by in core boxes. See Core Box.
Instrument for measuring expansion or contraction, the length of a metal sample, caused by changes in temperature or structure.
Ability of a casting to remain unchanged in size and shape under ordinary atmospheric conditions.
Dimensional Tolerance Grades
A system of classifying the tightness of tolerances for the purpose of defining accurately the tolerances involved, and for simplifying the communication process between customer and producer regarding what is wanted, and what is possible, respectively.
In solid and shell mold investment casting, a fine ceramic coating applied as a slurry to the pattern to produce maximum surface smoothness, followed by a cheaper conventional investment. See Investment Precoat.
A tank, preferably lined with rubber, epoxy, or other nonmetallic, into which die castings are dipped for cooling after leaving the machine.
A thin joint made by dipping of the brick in a thin mortar.
Teeming from the ladle into the casting mold without the use of a tundish.
Electric furnace in which the material is heated directly by an arc established between the electrodes and the work. See Dielectric Furnace.
Refers to the arrangement of a solidification pattern in a casting by establishment of high temperature gradients, whereby solidification of the metal begins at the point farthest from the metal entrance or sprue and the metal progressively freezes or solidifies to and including the sprue. See Solidification.
Indefinite term referring to any extraneous material entering a mold cavity and usually forming a blemish on the casting surface. See Mold Cavity.
A well employed in a gating system to entrap the first metal poured, which may contain dirt or unwanted particles (ineffective). See Slag Trap.
A casting containing an excessive amount of nonmetallic inclusions in the body of the metal. See Inclusion.
Disamatic molding is a type of sand molding process in which molten metal is poured into a mold made of sand to make Gray Iron Castings. Disamatic machines are designed to provide molds built for vertical casting and the molds are created in a vertical orientation. Disamatic machines create flaskless molds. Disamatic molding gets its name from the company that manufactures the molding machine, DISA. A Disamatic molding machine is a vertically parted sand molding machine. The vertical molding machine is often the choice for production of very close tolerance Gray Iron Castings. See Gray Iron, Hunter Molding.
Disappearing Filament Pyrometer (Optical Pyrometer)
A telescope in which a hot body is viewed through an eyepiece and temperature is measured by the matching color of a calibrated lamp filament with color of hot metal.
Carbon in solution in steel in either the liquid or solid state.
A pattern untrue to the specified dimensions. See Pattern.
A siliceous clay containing Bentonite used as bond in molding sands. See Molding Sands.
Distribution, Sand Grain
Variation or uniformity in particle size of a sand aggregate when properly screened by U.S. Standards screens.
Maximum strength of a metal when subjected to three principal tensile stresses at right angles to one another and of equal magnitude.
The cold worked metal formed on a polished surface during the processes of grinding and polishing.
Divorced Pearlite (Granular perlite, Spheroidite, Spheroidized cementite)
A mineral calcium-magnesium carbonate (Ca, MG (CO3)2) used as a flux in iron melting and smelting; also as a base in refractors.
Instrument used to detect and measure an accumulated dosage of radiation; in common usage it is a pencil-size ionization chamber with a built-in self-reading electrometer; used for personal monitoring. See Dosimeter, Pocket.
A pocket ionization chamber containing it own electrometer. An auxiliary charging device is usually necessary. See Dosimeter.
As applied to hypoeutectoid steel, a process of heating to above the upper critical point, Ac3, and holding at that temperature until complete solution of the carbide has been achieved then cooling rapidly and reheating immediately to above A3 and slowly cooling. See Ac3, Annealing.
Double Impression Method
A way of determining approximate Brinell hardness by placing a hardened steel ball between a specimen of known hardness and the metal to be tested and pressurizing in an arbor press. See BHN, Brinell Hardness.
Double Skin (Bottom Splash, Ingot Shell, Plaster)
A defect consisting of a secondary layer of metal sometimes found on top-poured ingots. See Ingot.
A retempering operation sometimes necessary for steel containing retained austenite which breaks down during cooling from the first tempering to form a new and hence untempered martensite.
Deadburn; not be mistaken for two firing.
A pin used between the sections of parted patterns or core boxes to locate and hold them in position, registering them correctly. See Core Box.
In air pollution control, a pipe for conducting bases down into a conditioner and subsequent cleaning.
The first channel, usually vertical, which the molten metal enters; so called because it conducts metal down into the mold.
Time lost from normal casting activity, due to unscheduled interruptions.
The taper on vertical surfaces of a pattern which allows easy withdrawal of the pattern from a compacted sand mixture without distorting or tearing of the sand and without excessive rapping and tearing of the mold walls.
See Pattern Draft.
A term used to temper, to remove pattern from mold, as an external contraction defect on surface of mold.
To remove a pattern from a mold.
Draw Bar (noun)
A wooden peg used for drawing patterns.
A plate attached to a pattern to facilitate drawing of a pattern from the mold.
A steel spike used to rap and draw a pattern from the sand; it is driven into the wood of the pattern, as opposed to a Draw Screw, which threaded.
A part of the mold, made of green sand, which may be drawn back to clear overhanging portions of the pattern. It is rammed up on a plate or arbor so that it can be lifted away. See Arbor, Mold, Pattern, Ramming.
Removing pattern from the mold or mold from pattern in production work. See Temper.
Sand which bas been dried by mechanical dryer prior to use in core making.
A material, as alcohol ammonium nitrate, sodium perborate and manganese oleate, added to a core or mold mixture to remove or reduce the water content.
Plates for supporting odd shaped cores during baking.
Chips, or small particles of metal removed from a test specimen for chemical analysis.
A casting defect caused by sand dropping from the cope or other overhanging section.
A heavy weight, usually ball or pear shaped, dropped from a height to break large pieces of metal scrap. Also used to strengthen warp castings.
A term for a pouring gate or runner leading directly into the top of the mold.
Drop Off or Drop Out
Sand falling from the Cope of a mold. See Drop.
Drop or Drop Out
The falling away of a body of sand when the mold is jarred or lifted.
Dropping the Bottom
Removal of the supporting props under the cupola bottom doors to permit emptying of the remaining contents. See Cupola.
Metal oxides and other scum on the surface of molten metal or in a metal or alloy (mostly a non-ferrous term).
A cylindrical refractory-lined ladle that is completely enclosed. A removable cover at the pouring spout permits addition of molten metal.
An electrically energized pulley or drum used for removing magnetic materials from sand, nonferrous borings and turnings, etc.
A term applied to spectrographic analysis.
Dry And Baked Compression Test
An AFS test to determine the maximum compressive stress that a baked sand mixture is capable of developing.
A grinding machine of heavy rollers or millers testing on a bed. Screens or slits allow fine material to pass through.
Property of a molded mass of sand dried at 221°F to 230°F and cooled to room temperature, to permit passage of gases through it.
Sand mixture that is baked to produce strong molds that are moisture free.
Dry Sand Casting
The process in which the sand molds are dried at above 212°F (100°C) before using.
Dry Sand Core
Dry Sand Mold
A mold from which the moisture has been removed by heating.
Dry Strength, or Dry Bond Strength
The maximum compressive, shear, tensile, or transverse strength of a sand mixture which has been dried at 220°F to 230°F (105°C to 110°C) and cooled to room temperature.
See Core Driers.
See Dielectric Oven.
A mold made of prepared molding sand dried thoroughly before being filled with metal. See Mold, Molding Sand.
Dual Metal Centrifugal Casting
Centrifugal castings produced by pouring a different metal into the rotating mold after the first metal poured.
A type of iron in which the graphite content takes spherical rather than flake form. Ductile iron is produced by adding magnesium. The spherical form of the graphite provides greater tensile strengths and flexibility than other types of iron. An iron/graphite composite in which the graphite exists in spheres or nodules, allowing the material to deform rather than fracture when placed under mechanical stress. Also called Nodular Iron. Iron in which carbon is in the form of spherical nodules. See Nodular Iron.
The property permitting permanent deformation by stress in tension with out rupture.
Term usually used in reference to melting metals or alloys in one type of furnace and transferring to another for holding, refining, etc. Common in the malleable field, where charges are melted in a cupola and transferred to air or electric furnaces for slight reduction of carbon and an increase in temperature.
Small solid particles created by the breaking up of larger particles by a process.
Penetrant is used to crack detection, which has a dye added to make it more readily visible under normal or black-lighting conditions. In the case of normal lighting, the dye is usually red and nonfluorescent. With black lighting, the dye is fluorescent and yellow-green in color.