| 摘要 |
A method for manufacturing a galvannealed steel sheet having excellent coating adhesion and sliding property in which a steel sheet is subjected to an oxidation treatment and reduction annealing, the method including performing the oxidation treatment under conditions such that the steel sheet is heated up to a temperature of 600°C or higher in an atmosphere which contains 1000 ppm or more of O 2 and the balance consisting of N 2 , CO, CO 2 , H 2 O and inevitable impurities and then heated up to a temperature of 700°C or higher in an atmosphere which contains less than 1000 ppm of O 2 and the balance consisting of N 2 , CO, CO 2 , H 2 O and inevitable impurities and performing the reduction annealing in an atmosphere whose dewpoint is 5°C or higher and which contains 1 vol.% or more and 15 vol.% or less of H 2 and the balance consisting of N 2 and inevitable impurities. |
