Glossary and Terms of the Foundry Industry

SFSA: Glossary of Terms - T

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Temper: 1) Reheating hardened, normalized or mechanically worked steel to a temperature below the critical range to soften it and improve impact strength. 2) The moisture content of a sand at which any certain physical test value is obtained, i.e., temper with respect to green compressive strength, permeability, retained compressive strength, etc. 3) To mix material with enough liquid to develop desired molding properties.
Temper Brittleness: Brittleness that results when certain steels are held within or cooled slowly through a certain range of temperature below the transformation range. The brittleness is revealed by notched-bar impact tests at room temperature or lower temperatures.
Temper Stressing: Quenching in water from the tempering temperature to improve fatigue strength.
Tempered Martensite: Martensite that has been heated to produce to BCC iron and a fine dispersion of iron carbide.
Temperature: Degree of warmth or coldness in relation to an arbitrary zero measured on one or more of accepted scales, as Centigrade, Fahrenheit, etc.
Temperature, Holding: 1) Temperature above the critical phase transformation range at which castings are held as a part of the heat treatment cycle, 2) The temperature maintained when metal is held in a furnace, usually prior to pouring.
Temperature, Pouring: The temperature of the metal as it is poured into the mold.
Tensile Strength: The maximum stress in uniaxial tension testing which a material will withstand prior to fracture. The ultimate tensile strength is calculated from the maximum load applied during the test divided by the original cross-sectional area.
Ternary Alloy: An alloy that contains three principal elements.
Test Lug: An ear like projection cast as part of the casting and later removed for testing purposes.
Thermal Conductivity: The property of matter by which heat energy is transmitted through particles in contact. For engineering purposes, the amount of heat conducted through refractories is usually given in Btu per hour for one square foot of area, for a temperature difference of one degree Fahrenheit, and for a thickness of one inch, Btu/hr·ft·F/in.
Thermal Contraction: The decrease in a linear dimension and volume of a material accompanying a change of temperature.
Thermal Expansion: The increase in a linear dimension and volume of a material accompanying a change of temperature.
Thermal Fatigue: Failure resulting from rapid cycles of alternate heating and cooling.
Thermal Shock: Stress developed by rapid and uneven heating of a material.
Thermal Spalling: Breaking up of refractory from stresses which arise during repeated heating and cooling.
Thermal Stability: Resistance of a material to drastic changes in temperature.
Thermocouple: A device for measuring temperatures by the use of two dissimilar metals in contact; the junction of these metals gives rise to a measurable electrical potential which varies with the temperature of the junction. Thermocouples are used to operate temperature indicators or heat controls.
Thermography: 1) The technique of obtaining a photographic record of heat distribution in a solid or fluid.
Tie Bar, Rod: Bar or rod-shaped part of the casting added to prevent distortion caused by uneven contraction between separated members.
Tight Flask: A type of flask which remains on mold during pouring. Lugs are normally provided for clamping cope and drag together for pouring.
Titanium: A white metallic element, melting point 1660°C (3020°F), having a high strength-to-weight ratio; useful in aircraft parts.
Tolerance: The permissible deviation of a dimension from the nominal or desired value. Minimum clearance between mating parts.
Tool Steel: Any high-carbon or alloy steel used to make a cutting tool for machining metals and for metal-casting dies.
Tooling Points: The fixed positions on the casting surfaces used for references during layout and machining.
Toughness: The ability of the metal to absorb energy and to deform plastically during fracture. Toughness values obtained in testing depend upon the test temperature, the rate of loading, the size of the test specimen, as well as the presence of a notch and its acuity.
Tower Oven: Vertical, continuous core oven with suspended shelves attached to sprocket-driven chains.
Tramp Element (Trace): Contaminant in the components of a furnace charge, or in the molten metal or casting, whose presence is felt to be either unimportant or undesirable to the quality of the casting.
Transfer Ladle: A ladle that may be supported on a monorail or carried in a shank and used to transfer metal from the melting furnace to the holding furnace or from furnace to pouring ladles.
Transformation (Temperature) Range: The critical temperature at which a change in phase occurs. To distinguish between the critical points in heating and cooling those in heating are referred to as the Ac points (c for Chauffage or heating) and those in cooling, Ar. (r for Refroidissement)
Tungsten: Steel-gray, metallic element, mp 3380°C (6116°F) used for electric lamp filament, x-ray tube target, and as alloy element in high-speed steels.
Turntable: The base on which a centrifugal casting mold rests.

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