Process for conditioning the copper or copper alloy external surface of a continuous casting mould comprising a nickel plating step and a nickel removing step

摘要

The external surface of a copper or copper alloy mould, which may comprise one or two rollers and is used for continuous casting of metal, is degreased, pickled in acid, polished and electrolytically coated with nickel, using an aqueous electrolyte solution of nickel sulphamate containing 60-100 gms. of nickel per litre with the mould acting as cathode. The mould is then used for a period, after which the coating is partly or wholly removed electrolytically, the mould acting as anode in an electrolyte comprising the same amount of nickel sulphamate plus 20-80 gms/litre of sulphamic acid giving it a pH of up to 2, and then a new nickel coating is applied.