recovers from an unstable condition, resulting in precipita-


tion and altered physical properties. Blister Undesirable on a body or a casting. A blister is a


defect on or near the surface of a casting, resulting from the expansion of gas in a subsurface zone. It is characterized by a smooth bump on the surface of the casting and a hole inside


the casting directly below the bump. Heel Metal left in a ladle after pouring or in the furnace


after or between tapping. Hot tear In both cases, this is the result of stress. In


Animals Blow holes A source of life for animals, but a defect


caused by gas in castings. Blow holes also can be holes in the head plate or blow plate of a core (used to shape the casting’s interior) blowing machine through which sand is transport-


ed from the reservoir into the core box. Bull ladle If a normal ladle is too small, you’ll need


something with a bit more weight behind it. A bull ladle is a large container for transporting and pouring molten metal.


T e term frequently used to designate a transfer ladle. Fin Similar in shape to a fi n on a fi sh, this term means a thin projection of metal on a casting resulting from imper-


fect mold or core joints. Ghost You will understand the reference only if you


believe in ghosts. In metalcasting, a ghost is a light colored streak just visible on a freshly machined surface due to local segregation of impurities such as phosphorus and sulfur dur-


ing solidifi cation. Pig An ingot of virgin or secondary metal (as rejected


casting and scrap) to be remelted for use. Rat tail Gross to look at on a rat or a casting, a rat tail is


a casting surface defect. It is an irregular line on the casting resulting from thermal deformation of a sand mold during


fi lling with molten metal. Ram T e process of packing sand in a mold using a manual, pneumatic or mechanized ramming device.


Around the House


Bath A hot bath is relaxing, unless it’s as hot as iron’s melting point. A bath is molten metal on the hearth of a


furnace, in a crucible or in a ladle. Gate In life, it’s used to keep people out. In metalcast- ing, it lets metal in. T e gate is the portion of the gating


system where molten metal enters the mold cavity. Rake T e angular relationship between the tooth face of


a machining cutting tool and a given reference plane. Stool A device that supports. In metalcasting, it’s used on molding machines to hold pattern plates, or it’s a refrac-


Aging As time passes, the “physical properties” of a


body changes, and castings are no exception. Aging is a change in casting structure by which a metal or alloy


Dae ra sum que perum cullabo. Exped quidi nate elisimus sum est, quia nos ipsanturio. Derepudi dolupta tendae quid modis vollectis int


Anatomy


tory block used to support a crucible in a furnace. Vent At home, vents are essential to keep the house


warm during winter. In metalcasting, it’s an opening or pas- sage in a mold or core to facilitate the escape of gases when the mold is poured.


Nov/Dec 2011 | METAL CASTING DESIGN & PURCHASING | 45


metalcasting, a hot tear is an irregularly shaped fracture in a casting resulting from stresses set up by steep thermal gradi-


ents within the casting during solidifi cation. Impregnation T is may make your castings be fruitful and multiply. Impregnation is a treatment of castings with a


sealing medium to stop pressure leaks. Scab Rough surface defects. In castings, they are rough,


slightly raised surface blemishes, crusted over by a thin, porous layer of metal under which is a honeycomb or cavity


that usually contains a layer of sand. Snot Nearly the same meaning in both situations. In technical metalcasting terms, snot is a creamy-white cerox-


ide defect found imbedded in an iron or steel casting. Veins On a casting, a vein is a discontinuity on the


surface appearing as a raised, narrow, linear ridge that forms upon cracking of the mold or core due to sand expansion during fi lling.


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