PRODUCTION OF COLD ROLLED STAINLESS STEEL, EXCELLENT IN SURFACE GLOSS AND CORROSION RESISTANCE

• Main Authors: KANEKO MICHIRO, SUMITOMO HIDEHIKO
• Format: Patent
• Language: English
• Published: 10.02.1997
• Edition: 6
• Subjects: ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FERROUS OR NON-FERROUS ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide a stainless steel excellent in corrosion resistance as well as in surface gloss by immersing a bright annealed cold rolled stainless steel strip containing specific amounts of Cr in warm water of a specific temp. for specific time and then immersing this strip in a nitric acid solution of a specific concentration for a specific time. SOLUTION: A bright annealed cold rolled stainless steel strip and sheet of 12-20wt.% Cr content or a cold rolled material having surface glossiness and roughness equal to those of the bright annealed material is treated. The material to be treated is immersed in warm water of >=40 deg.C liquid temp. for >=10sec. The material to be treated is immersed in a nitric acid solution of 5-71% concentration for >=10sec. The inclusions, dissolved and removed in the acid pickling stage, remain at the metal surface and become the origin of corrosion, by which corrosion is brought about and surface gloss is deteriorated. The material to be treated is immersed in warm water to dissolve the inclusions. When the liquid temp. is <40 deg.C, the inclusions cannot be dissolved sufficiently.