Continuous casting method for steel

A continuous casting method for steel using a vertical bent continuous casting device which includes a vertical section configured to pull out a slab from a casting mold downward in a vertical direction, a bent section in which the slab pulled out from the vertical section is bent, and a first cooling zone including rolls and cooling spray nozzles in the vertical section, the method comprising:

• in the first cooling zone, setting an air-water ratio A1/R1 which is a ratio of an amount of air A1 (L/min) to an amount of water R1 (L/min) per one of the cooling spray nozzles to 10 or more and setting an impinging pressure of cooling water colliding with a surface of the slab through the cooling spray nozzles to 12 gf/cm2 or more,
• setting a cooling intensity W1×t1 defined as a product of a cooling water density W1 (L/min/m2) in the first cooling zone and a time t1 (min) during which the slab passes through the first cooling zone to 350 or more,
• setting a recuperating time t2 of the slab from having passed through the first cooling zone until reaching the bent section to 0.5 min or more, and
• wherein a height of the vertical section is 0.5 m or more and 3.0 m or less.