USE OF A SOLUTION CONTAINING SULPHATE IONS FOR REDUCING THE BLACKENING OR TARNISHING OF A METAL SHEET DURING THE STORAGE THEREOF AND METAL SHEET TREATED WITH SUCH A SOLUTION

摘要

The present invention primarily relates to a process for the treatment of a steel sheet comprising a steel base coated with at least one side of the sides with a coating comprising at least zinc and magnesium to reduce the blackening or discoloration of the steel sheet during storage of the steel sheet, in more mol / ℓ concentration relates to the use of an aqueous treatment solution containing a sulfuric acid ion (SO ₄^2-). The present invention also relates to a metal sheet treated with the solution.