| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel material having high austenite grain roughening temperature.SOLUTION: There is provided a steel material having high austenite grain roughening temperature containing less than 0.4 wt.% of carbon, less than 0.06 wt.% of aluminum, less than 0.01 wt.% of titanium, less than 0.01 wt.% of niobium, less than 0.02 wt.% of vanadium, and fine oxide particles containing silicon and iron distributed in a steel fine structure. The steel material can have the fine oxide particle distributed in the fine structure capable of limiting ferrite recrystallization with distortion level of up to at least 10.0%, at a temperature up to 750°C and for retention time of 20 minutes. The steel material can be manufactured by: forming cast reservoir of a molten carbon steel introduced between casting rolls and having all oxygen content of at least 70 ppm, normally less than 250 ppm, and free oxygen total amount of 20 to 60 ppm; and continuous casting a steel strip by rotating the casting rolls in mutual direction. |
