| 摘要 |
PROBLEM TO BE SOLVED: To propose a steel continuous casting method capable of reducing center segregation in a cast piece thickness central portion and obtaining a continuous casting cast piece excellent in hydrogen induced cracking resistance (HIC resistance).SOLUTION: There is provided a steel continuous casting method for bulging a cast piece after passing through a casting mold of a continuous casting machine and then applying a pressure to the bulged cast piece in a soft reduction zone. An amount of bulging is set to 3-10 mm, a pressure reduction gradient in the soft reduction zone is set to 0.3-1.0 mm/min, a specific water content in a secondary cooling zone at a cast length of 2.5 m from a portion right under a casting mold is set to not less than 0.15 L/kg, an average value of a fluctuation in a cast piece thickness at a position right in front of the soft reduction zone is set to not more than 0.1 mm by regulating a specific water content and a width cut amount in the secondary cooling zone downstream of a portion at the cast length of 2.5 mm from the portion right under the casting mold, and a sectional average temperature of a cast piece short side portion at a soft reduction start position is set to not less than 1050°C, thereby setting an actual reduction speed of the cast piece to 0.3-1.0 mm/min and a dendrite primary arm interval of a cast piece thickness central portion to not more than 1.6 mm.SELECTED DRAWING: Figure 5 |
