| 摘要 |
PROBLEM TO BE SOLVED: To provide a continuous casting method for steel which prevents surface cracking by nonuniformity of the solidification shell thickness due to transformation from δ iron to γ iron in medium carbon steel involving a peritectic reaction.SOLUTION: In a casting mold for continuous casting, a circular concave groove is provided in the range of an inner wall surface from an arbitrary position above the meniscus to a position lower than the meniscus by a length R (mm) or more determined from the cast slab drawing speed Vc (m/min). The circular concave groove 2 is filled with a metal having a thermal conductivity of 80% or less to the thermal conductivity of the casting mold (copper) to form a low-thermal-conductivity metal-filled part 3. The filling thickness H (mm) of the metal in the low-thermal-conductivity metal-filled part 3 and the diameter d (mm) of the low-thermal-conductivity metal-filled part 3 meet the relational expression 0.5≤H≤d. A continuous casting method for steel uses the casting mold for continuous casting and extracts heat from the casting mold for continuous casting so that the casting mold heat extraction amount Q is equal to or smaller than 14.0 (MJ/ton steel). |
