| 摘要 |
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 product before surface treatment. |
