Patent ID: 6358335
Filing Date: 2002-03-19
Classification: C21D,C22C

Abstract:
A steel continuous casting slab with no surface cracks, comprising:C: about 0.05 to 0.18 wt %, Si: about 0.6 wt % or less, Mn: about 0.80 to 1.80 wt %, P: about 0.030 wt % or less, S: less than 0.004 wt %, Al: about 0.050 wt % or less, V: about 0.04 to 0.15 wt % and N: about 0.0050 to 0.0150 wt %; at least one of Ti: about 0.004 to 0.030 wt % and B: about 0.0003 to 0.0030 wt % within a range satisfying the following equation 1; and at least one of Ca: about 0.0010 to 0.0100 wt % and REM: about 0.0010 to 0.0100 wt % within a range satisfying the following equation 2, with the balance being iron and inevitable impurities: 5.0&lE;[V](wt %)/([N](wt %)âˆ’0.292Ã—[Ti](wt %)âˆ’1.295Ã—[B](wt %))&lE;18.0â€ƒâ€ƒ1 [Mn](wt %)Ã—([S](wt %)âˆ’0.8Ã—([Ca](wt %)âˆ’110Ã—[Ca](wt %)Ã—[O](wt %))âˆ’0.25Ã—([REM](wt %)âˆ’70Ã—[REM](wt %)Ã—[O](wt %)))Ã—103&lE;0.75â€ƒâ€ƒ2.