Method for pickling metallic surfaces

摘要

A method for removing rust and/or scale from a metal surface, comprising contacting said metal surface with a homogeneous pickling solution comprising a major amount of a halogenated hydrocarbon solvent, an effective solubilizing amount of at least one alcohol solubilizer, an effective pickling amount of an aqueous phosphoric acid and preferably a mixture of phosphoric and sulfuric acids as pickling agent, and an effective inhibiting amount of at least one inhibitor for protecting the bare metal surface; wherein said contacting is effected at a temperature from room temperature up to the boiling point of said pickling solution; and wherein said contacting is continued for a time sufficient to substantially remove said rust and/or scale. This pickling system is advantageously used to prepare metals for phosphating in halocarbon-based phosphating baths.