Abstract A process for the production of coin blanks suitable for minting into coins, includes providing metal coin core pieces of 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 moving the container angularly about a horizontal axis, at a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m 2 to about 1400 A/m 2 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 pieces and a thickness of from about 2 to about 4 times the face 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.
A process for the production of coin blanks suitable for minting into coins, including providing metal coin core pieces of 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, loading a charge of core pieces 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 about 1/2 of the container volume, placing the container in an electroplating bath, electroplating a metallic cladding on the core pieces, while moving the container angularly about a horizontal axis, at a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m 2 to about 1400 A/m 2 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 of from about 2 to about 4 times the face thickness has been deposited on the circumference of each core piece, removing the cladded core pieces from the container, and heating the cladded core pieces 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.
Claim 2
Dependent Claim
253 words
A process for the production of coin blanks suitable for minting into coins, including providing metal coin core pieces of 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, loading a charge of core pieces 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 about 1/2 of the container volume, placing the container in an electroplating bath, electroplating a metallic cladding on the core pieces, while moving the container angularly about a horizontal axis, at a voltage of from about 6 volts to about 18 volts and a current density of from about 470 A/m 2 to about 1400 A/m 2 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 of from about 2 to about 4 times the face thickness has been deposited on the circumference of each core piece, removing the cladded core pieces from the container, and heating the cladded core pieces 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.
Claim 3
Dependent Claim
32 words
A process according to claim 1 wherein the core pieces are of low carbon steel, the metallic cladding comprises nickel, and the electroplating bath has a pH of less than about 3.5.