| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a hot dip galvannealed steel sheet which has excellent plating adhesion and sliding properties even in the case an Si content is high. <P>SOLUTION: The steel sheet is produced through oxidation treatment and reduction annealing. In the oxidation treatment, the steel sheet is heated until the steel sheet temperature reaches ≥600°C in an atmosphere comprising ≥1,000 ppm O<SB POS="POST">2</SB>, and the balance N<SB POS="POST">2</SB>, CO, CO<SB POS="POST">2</SB>and H<SB POS="POST">2</SB>O with inevitable impurities, and next, the steel sheet is heated until the steel sheet temperature reaches ≥700°C in an atmosphere comprising <1,000 ppm oxygen O<SB POS="POST">2</SB>, and the balance N<SB POS="POST">2</SB>, CO, CO<SB POS="POST">2</SB>and H<SB POS="POST">2</SB>O with inevitable impurities. The reduction annealing is performed in an atmosphere having a dew point of ≥5°C and comprising H<SB POS="POST">2</SB>of 1 to 15 vol.%, and the balance N<SB POS="POST">2</SB>with inevitable impurities. <P>COPYRIGHT: (C)2012,JPO&INPIT |
