| 摘要 |
Problems caused by oxides formed on a surface of a steel sheet containing Cr are solved. There is provided a method for producing a high-strength hot-dip galvanized steel sheet having good adhesion of the coating and a good surface appearance and a method for producing a high-strength galvannealed steel sheet. A high-strength hot-dip galvanized steel sheet is produced by a method that includes a first heating step of holding a steel sheet at a specific temperature for a specific time in an atmosphere having a specific H 2 concentration and a specific dew point, the steel sheet having a specific composition, a cooling step of cooling the steel sheet after the first heating step, an electrolytic treatment step of subjecting the steel sheet after the cooling step to electrolytic treatment under specific conditions, a second heating step of holding the steel sheet after the electrolytic treatment step at a specific temperature for a specific time in an atmosphere having a specific H 2 concentration and a specific dew point, and a coating treatment step of subjecting the steel sheet after the second heating step to hot-dip galvanizing treatment. |
