Z94.12.2 Foundry/Casting

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PANORAMIC ANALYZER. An instrument for detecting the level of sounds in a foundry to assure compliance with OSHA standards. The output is either on an oscilloscope or chart.

PARTING COMPOUND. A material dusted or sprayed on patterns or mold halves to prevent adherence of sand and to promote easy separation of cope and drag parting surfaces when cope is lifted from drag.

PATTERN. A form of wood metal or other materials around which molding material is placed to make a mold for casting metals.

PATTERN, INVESTMENT MOLDING. A reproduction with an expendable material of the object to be cast and usually formed in a pattern die.

PATTERNMAKER'S SHRINKAGE. Shrinkage allowance made on all patterns to compensate for the change in dimensions as the solidified casting cools in the mold from freezing temperature to room temperature. Patterns are made larger by the amount of shrinkage characteristic of the particular metal in the casting and the amount of resulting contraction to be encountered. Rules or scales are available for use. (See SHRINKAGE, PATTERNMAKER'S)

PATTERN, MASTER. Pattern constructed with double shrinkage allowance from which production patterns are made.

PEARLITIC MALLEABLE. The product obtained by a heat treatment of white cast iron which converts some of the combined carbon into graphite nodules but which leaves a significant amount of combined carbon in the product. Pearlitic malleable may also be obtained through the use of additional alloys which retard the breakdown of pearlite.

PEEN. (l) Flat-pointed end of a rammer used in ramming sand into a mold. (2) Process of repairing slight leaks in casting by repeated impacts of a blunt tool or peening hammer. (3) Peening action obtained by impact of metal shot.

PENCIL CORE. A core projecting to the center of a blind riser to admit atmospheric pressure to force out feed metal.

PENCIL GATE. Gating directly into the mold cavity through the cope by means of one or more small vertical gates connecting the pouring basin and mold cavity.

PENETRATION, METAL. Condition where molten metal has penetrated into the face of a sand mold beyond the midpoint of the first layer of sand grains, resulting in a mixture of metal and sand adhering to the cast surface.

PERLITE. A highly siliceous volcanic rock which can be expanded into a porous mass of particles by heating. Perlite can be used as an insulation in foundry sand mixes, or as a riser topping, or as sleeves in steel casting.

PERMANENT MOLD. A metal mold of two or more parts that is used repeatedly for the production of many castings of the same form. Liquid metal is poured in by gravity. Not an ingot mold.

PERMEABILITY. As applied to sand molds, permeability means the property of the sand which permits passage of gases. The magnetic permeability of a substance is the ratio of the magnetic induction of the substance to the intensity of the magnetizing field to which it is subjected.

PH. A symbol denoting the negative logarithm of the concentration of the hydrogen ion in gram atoms per liter. Used to express both acidity and alkalinity. pH = log 1/H per liter.  An important factor in foundry sand control where a pH = 7 is neutral, values less than 7 are acidic and greater than 7 are basic. (The symbol is derived from the French "pouvoir hydrogène'' or "hydrogen power''.)

PHENOLIC RESIN. A resin made by polmerization of a phenol with an aldehyde. Used as a binder for cores and sand molds.

PIG IRON. Cast iron generally produced by the reduction of iron ore in the blast furnace; also the over-iron in the foundry poured into pig molds.

PINHOLE POROSITY. Very small holes scattered through a casting, possibly caused by microshrinkage or gas evolution during solidification.

PIT. A sharp depression in the surface of metal.

PLASTER MOLDS. With plaster as the mold material, liquid plaster slurry is poured over the pattern, allowed to harden and the pattern is then removed. The hardened mold is then heated to drive off the moisture. Smooth finishes and close tolerances are the advantages. Aluminum and copper-base alloys are cast by this process.

PLASTER OF PARIS. A semi-hydrated form of calcium sulphate made by sintering gypsum at 120°-130°C (248°-266°F).

PLUMBAGO. Graphite in powdered form. Plumbago crucibles are made from this graphite plus clay.

POROSITY (SAND). The ratio of volume of the pores or voids to volume of the entire mass, usually expressed as a percentage. Generally the volume of pores is obtained by determining the amount of water or gas absorbed by the mass, and therefore does not include the volume of sealed pores. The result so obtained is "apparent'' rather than "true'' porosity. (Not synonymous with permeability.)

PORT. Opening through which molten metal enters the injection cylinder of a plunger machine or is ladled into the injection cylinder of a cold-chamber machine.

POURING. Transfer of molten metal from furnace to ladle, ladle to ladle, or ladle to molds.

PREFORMED CERAMIC CORE. A preformed refractory aggregate inserted in a wax or plastic pattern or shape (the interior of that part of a casting which cannot be shaped by the pattern). Sometimes the wax is injected around the preformed core.

PRODUCTION FOUNDRY. A foundry engaged in manufacture of castings in large quantities, usually highly mechanized to minimize manual labor. May be either jobbing or captive foundry.

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