Patent ID: 10988836

Abstract:
A method for producing a high-strength galvanized steel sheet having excellent fatigue resistance properties. The method includes an oxidation processing in which a steel sheet is heated at a temperature of 400 to 750° C. in an atmosphere having an O2 concentration of 1000 ppm by volume or more and a H2O concentration of 1000 ppm by volume or more, and the steel sheet is heated at a temperature of 600 to 850° C. in an atmosphere having an O2 concentration of less than 1000 ppm by volume and a H2O concentration of 1000 ppm by volume or more. The method also includes reduction-annealing in which the steel sheet is heated at a heating rate of 0.1° C./sec or more to a temperature of 650 to 900° C. in an atmosphere having a H2 concentration of 5 to 30 vol % and a H2O concentration of 10 to 1000 ppm by volume.