PROCESS FOR THE PRODUCTION OF COIN BLANKS

摘要

A process for the production of coin blanks suitable for minting into coins, includes providing metal coin core pieces of a disc-like shape each having opposed faces from about 14 mm to about 40 mm in diameter and a face to face thickness of from about 0.5 mm to about 2.6 mm. A charge of core pieces is loaded into a non-conducting perforated container with a diameter of from about 15 cm to about 50 cm, the number of core pieces in the container being such that the core pieces occupy from about 1/4 to 1/2 of the container volume. The container is placed in an electroplating bath, and a metallic cladding is plated on the core pieces, while the container is being moved angularly about a horizontal axis, as a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m2 to about 1400 A/m2 based on the exposed area of the charge, until a plating thickness of from about 0.03 mm to about 0.08 mm of metal has been deposited on each face of each core piece and a thickness has been deposited on the circumference of each core piece. The cladded core pieces are then removed from the container and heated to form a metallurgical bond between the metallic cladding and core piece of each cladded core piece and to reduce the hardness to less than 65 on the Rockwell 30T hardness scale.