< METALS SUMMARY
METALS KEYWORDS
ALLOY: A combination of two or more elements which produce a distinctive metallic material. Sometimes used as a generic reference to the entire aluminium group.
AMALGAM: Mercury alloyed with one or more other elements (gold for example).
ANNEALING: A heat treatment that raises an alloys temperature to a minimum level, then slowly cools inducing an alteration in it’s crystalline structure. Usually used to prevent stress cracking of cold worked metals (beaten copper etc).
ASSAY: The determination of an alloy’s composition. Assay Office official establishment confirming and approving the content of (precious) metal alloys such as gold.
ASTM: (abbr.) American Society for Testing Materials – a standards organisation.
BASE METALS: Group of metals, principally lead and lead alloys.
BOILING POINT: The minimum temperature at which a metal or alloy can evaporate to atmosphere.
BS (EN): (abbr.) British Standards (European Compliant).
BRASS: A copper/zinc alloy common in architectural design.
BRONZE: Strictly speaking, an alloy of copper and tin only, but commonly used as a generic term for the wider group of copper based alloys as used in art and design (brasses excepted).
CARBON STEELS: Group of ferrous alloys which includes low carbon steel (mild steel), low alloy steel (high tensile steel) and some special steels (Cor-ten).
CAST IRON: A ferrous casting material composed primarily of iron and carbon elements.
COLD ROLLED (REDUCED): Wrought sections formed by a cold working process (below re-crystallaisation temperature). Usually offers a significantly better quality of surface finish than hot rolled material.
CONDITION: The metallurgical condition of a supplied casting or wrought section – for instance heat treated, annealed, hardened, half hard, soft etc. May also be indicated by a numeric or letter code.
COR-TEN™: A high strength ‘weathering’ type carbon steel, additionally alloyed with copper and other metals. Produced by the USX Corp.
DUCTILE: The ability of a metal to be easily shaped by drawing.
EUTECTIC ALLOY: An alloy (eg. aluminium/silicon, or copper/silver) that is soluble in the liquid state and insoluble in the solid state. Eutectic Composition: the relative proportion and specific temperature, at which such an alloy melts or solidifies, without first passing through a transitional ‘semi-solid’ stage.
EXOTIC METALS: Metals and alloys not in common use.
FERROUS METALS: Group of metals containing ferric compounds – iron and steel.
HEAT TREATMENT: The metallurgical conditioning of an alloy as part of a production process. Includes annealing, hardening and tempering.
HOT ROLLED (REDUCED): Wrought sections formed through hot working (above re-crystallaisation temperature).
LEADED GUNMETAL: An alloy composed of primarily of copper, with added tin, zinc and lead – a common art and commercial founding alloy.
INGOT: Bar of supplied metal for the furnace, usually to a standard size, shape and weight.
INGOT MOULD: mould (usually fashioned from cast iron) for forming ingot. Also called BILLET or BAR.
INTERMETALLIC: An alloy (eg. Cu60Zn40 brass) whose component elements are of differing crystalline structures, valencies and also have opposing electrons (electropositive & electronegative).
ISO: (abbr.) International Organisation for Standardisation
KARAT: System for defining gold fineness or purity, expressed as a round fraction of twenty four parts (ie 75% gold: 18k [18/24]).
LIGHT METALS: Group of low density metals, primarily aluminium, magnesium and zinc.
MALLEABLE: The ability if a metal to be easily shaped by hammering.
MELTING POINT: The minimum temperature at which a metal or metal alloy is fully fluid.
METAL: Strictly speaking a specific group of elements, but also often used as a general term for alloy combinations.
NOBLE METALS: Group of metals primarily gold, silver, and platinum. Also PRECIOUS METALS.
PANNED OVER: A type of non-welded joint common in copper and lead work whereby two free edges are folded into each other (similar in form to clasping the fingers of both hands), to create a secure joint.
PHASE: Metals alloyed in certain proportions (eg < 37% zinc in copper), form into a solid solution, or single alpha phase. If this proportion is exceeded (> 40% zinc in copper), an intermetallic compound is formed. A second (beta) phase can be identified in these alloys under microscopic inspection.
PIG: Cast iron ingot.
SILICON BRONZES: A copper/silicon based group of alloys, some classed metallurgically as brasses. The most common art founding alternative to leaded gunmetal; includes the proprietory alloys Everdur™ & Herculoy™.
SMELTING: Processing an ore to separate out impurities, producing a refined metallic material.
SOLID SOLUTION: An alloy (eg either Cu63Zn37 brass, or copper/nickel alloys in all proportions), whose constituent elements are completely soluble in one another.
STAINLESS STEELS: Group of corrosion resistant steels alloyed with chrome and (in certain grades), nickel additions. The most important stainless grade used in art and design applications is the austenitic 316 (L) grade.
WROUGHT METALS: Metals for fabrication, normally supplied by stockholders in a wide variety of preformed sheets and sections.
FINISHING INDEX >
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