Patent ID: 8197663

Claim:
A method for plating tin, the method comprising the steps of: a) electroplating tin onto a steel strip in an acidic electroplating bath comprising an electrolyte, stannous ion and an anion, and forming a plated strip comprising a plated tin surface comprising a surface layer of tin; b) performing one or more rinses; c) optionally exposing the plated tin surface either to (i) an aqueous solution comprising about 0.01 wt % to 10 wt % of a polybasic organic acid having one or more sulfonic acid groups and optionally one or more weaker acid functionalities, a salt thereof or anhydride thereof, or a mixture of two or more of the polybasic organic acid, the anhydride thereof, and the salts thereof, or (ii) a solution of about 0.01 vol % to 10 vol % of an organic compound in water, the organic compound selected from the group consisting of acetone, gamma-butyrolactone, and mixtures thereof; d) heating the plated strip to at least the melting point of tin but to less than the melting point of the steel strip; and e) either (i) quenching the plated strip in water or (ii) quenching the plated steel strip in a solution of about 0.01 vol % to 10 vol % of an organic compound in water, the organic compound selected from the group consisting of acetone, gamma-butyrolactone, and mixtures thereof; in which, if the electrolyte is not a polybasic organic acid having one or more sulfonic acid groups and optionally one or more weaker acid functionalities, a salt thereof or anhydride thereof, or a mixture of two or more of the polybasic organic acid, the anhydride thereof, and the salts thereof, the method comprises either step c) or step e)(ii) and further wherein said method comprises either step c)(ii) or step e)(ii), but not both step c)(ii) and step e)(ii).