DESCALING METHOD FOR STAINLESS STEEL AND CR OR/AND NI ALLOY STEEL, AND COMPOSITION OF PICKLING SOLUTION AND RECYLING METHOD OF PICKLING WASTE SOLUTION

摘要

A method of removing oxidized and carbide scales formed on the surface of alloy steel during heat treatment of stainless steel and chromium and / or nickel alloy steel production is disclosed.;This method involves treating scaled alloy steel with a pickling solution containing nitrate and fluoride salt as essential components.;The nitrate and fluoride salts contained in the pickling solution used in the method of the present invention have a rather excellent scale removal efficiency, and do not generate harmful gases, compared to the conventionally used mixed acid of nitric acid and hydrofluoric acid. Not only is the treatment easy, but the conventional pretreatment may be omitted.;The pickling solution may contain an auxiliary component.;Also provided are pickling compositions containing nitrates and fluoride salts and methods for regenerating pickling liquor.