Method of cleaning a metal surface

• Main Authors: Meskers, Jr., Donald A, Tippett, Roger John Arthur
• Format: Patent
• Language: English
• Published: 19.02.2002

The present invention relates to cleaner compositions and processes useful for removing scale from metal surfaces. The present invention also relates to cleaner compositions and processes that have reduced base metal loss without inhibiting or significantly inhibiting scale removal from metal surfaces. More particularly, the present invention provides for cleaner compositions and processes for removing magnetite containing scale from metal surfaces, especially in steam generating equipment, and especially high strength metals, such as high strength steels, steels used for pressure to vessel plating, welded metals including welded higher strength steels and welded steels used for pressure vessel plating, steels galvanically coupled to stainless steels, and steels containing heat affected zones resulting from a welding process. Methods and compositions for controlling corrosion of high strength steels in the presence of a cleaning solution for removing iron oxide scale from metal surfaces. A benzotriazole or benzimidazole compound is added to a combination of ethoxylated mercaptan and/or oxidized ethoxylated mercaptan and 1-hydroxyethylidene-1,1-diphosphonic acid. The composition is added to an aqueous system, such as a steam generating system, to remove scale from the metal surfaces.