To provide a continuous casting method with which center segregation in a cast slab can sufficiently be reduced without developing the internal crack caused by light rolling reduction, in the continuous casting of steel having ≥0.4 mass% C content.
In the method for continuously casting steel having ≥0.4 mass% C content, based on Mn, P and S contents in the steel to be cast, the performance or the non-performance of the light rolling-reduction for rolling-reducing the cast slab at the solidified-end stage with the rolls at the preset rolling-reduction speed, is decided. When the non-performance of the light rolling-reduction is decided, further, the continuous casting speed is made to be slow speed in comparison with the performance time of the light rolling reduction to adjust the over-heat degree of the molten steel. Further, when an index X designated in the expression (1), X=0.5×[Mn]/[S]+0.2/[P] (wherein, [Mn], [P], [S] are the contents (mass%) of respective components in the molten steel) has a lower value than a prescribed value decided from a quality demanding level, the light rolling reduction is decided to be non-performance.
ISHIBASHI YASUSHI
ARAI MASAYUKI
KINOMOTO YASUO
Hisataka Tanaka
Next Patent: STEEL PLATE LINE-HEATING METHOD