| 摘要 |
PROBLEM TO BE SOLVED: To obtain a slab cast piece of excellent interior quality in steel continuous casting, while preventing the central segregation. SOLUTION: In this continuos casting method of steel, in order to stably produce a slab of the central segregation, molten steel superheat degree in a tundish in excellent casting should be at 20 deg.C or less to generate a minute equiaxed grain. In addition, the crater end angle obtained from the following equation should be over 1 deg. or more. Equation:θ=2.arctan[k.k/(Vc.t)+Δt/2] (In the equation, Q; crater end angle (deg.), K; the solidification constant (mm/√min), Vc; the casting speed (mm/min), t; the casting slab thickness (mm),Δt; roll squeezing gradient in a solidification advanced stage division (mm)). In addition, it is the more desirable condition that a vertical continuous casting machine is used and the casting slab thickness is 300 mm or more.
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