VOCABULARY TERM: COINABILITY

Coinability The suitability of a metal or alloy to take a sharp, clear, struck impression between dies in a coining press under normal coinage operations, at room temperature (cold coining). Not all metals have the same property of surface displacement that allows surface metal to flow easily into die cavities when struck. Metals ranking high in coinability possess these characteristics and include gold, silver and copper. Alloys ranking high in coinability include bronze, brass, copper nickel, nickel-silver and others. Metals that are hard, brittle, or for other characteristics would rank low in coinability, include steels, zirconium, titanium, and alloys such as nickel-chromium.

Coinage alloys must fill all die cavities with ease during striking, and by surface displacement must flow into these die cavities from the mass of the blank. Ideally this must occur during high-speed coining without excessive die pressures. Although there is some correlation between ductility and malleability to coinability, metals are ranked in coinability only by this ease of moving surface metal into the cavities of coin dies during striking in coining presses.

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