Metal alloy for coin production
AssigneeThe United States Mint
InventorsTsineng T. Ying, Richard R. Robidoux, Uvon Tolbert
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Abstract
The metal alloy is a possible replacement for/alternative to cupronickel cladding material used on currently-circulating clad coins. In the preferred embodiment, the (steel) metal alloy cladding material comprises 73-77% iron, 22-26% nickel, 0.2-0.5% carbon, and 1-5% manganese. The cladding material has an International Annealed Copper Standard (IACS) conductivity of less than 2%, a permeability of approximately 1.0-1.1, and a hardness value of 50-70 HRC 15 T (Rockwell Hardness). In alternative embodiments, the steel alloy comprises a monolithic coin or a core that may be plated with other metals.
Claims19
A cladding material for coins, the cladding material comprising:
- 73-77% iron;
- 22-26% nickel;
- 0.2-0.5% carbon;
- and,
- 1-5% manganese;
- wherein the cladding material comprises at least outer layers of a coin.
A method for making a steel alloy clad coin, the method comprising the steps of:
- (a) assembling a steel alloy comprising 73-77% iron, 22-26% nickel, 0.2-0.5% carbon, and 1-5% manganese;
- (b) cladding a copper core with the steel alloy by sandwiching a copper core between two layers of the steel alloy to create a steel alloy clad coin.
Dependencies are inferred from the claim text.