| 摘要 |
The present invention makes it possible to set soft reduction conditions according to the thickness of a slab casting piece and thereby prevent occurrences of center segregation in the casting piece because of insufficient amounts of reduction and occurrences of internal casting piece cracking because of excessive amounts of reduction. Provided is a continuous casting method for steel that continuously casts a region of a casting piece 10 with a thickness of 160 - 350 mm and a width of 1600 - 2400 mm from a point in time equivalent to a solid phase rate of 0.1 at the middle part of the thickness to a point in time equivalent to the solid phase rate at the middle part of the thickness being the flow limit solid phase rate while performing reduction at a soft reduction zone 14 in which a plurality of pairs of casting piece support rolls are installed, wherein the thickness (D) of the casting piece, the reduction gradient (Z) of the soft reduction zone, and the drawing speed (V) for the casting piece satisfy the relationship in the following Equation (1) and Equation (2), where α is the coefficient (non-dimensional) of thickness, Do the thickness (mm) of a reference casting piece directly below a casting mold, and β and γ coefficients determined by the width W (mm) of the casting piece. 0.3/(V × α) < Z <1.5/(V × α) … (1) α = β × (D/Do) + γ … (2) |
