Steel product excellent in corrosion resistance and corrosion fatigue resistance, and surface treatment method therefor

• Main Authors: IKAI KAZUYA, SUZUKI TAKESHI, ONO YOSHIKI
• Format: Patent
• Language: English
• Published: 18.01.2007
• Subjects: 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; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

The invention provides a steel product excellent in corrosion resistance and corrosion fatigue resistance, comprising a, coating film on the surface of the steel product, wherein a ratio of the number of Al atoms to the total number of Fe, C, Al, P and O atoms and optionally added Si, Mn and Cr atoms is 0.5% or more in an average composition of the coating film, and the number of Al atoms in the average composition of the coating film is higher than the number of Al atoms in an average composition of the steel pro duct before surface treatment.