| 摘要 |
PROBLEM TO BE SOLVED: To provide a continuous casting method by which a cast slab excellent in HIC(hydrogen induced cracking)-resistant characteristic and remarkably reduced in macro segregation and semi-macro segregation for producing a steel plate, is produced and a continuously cast slab. SOLUTION: (1) In a continuous casting method for low carbon steel, non-solidified portion of the low carbon steel having <0.1% carbon content is stirred with electromagnetic force and also, the cast slab containing non-solidified part at the downstream side of the electromagnetic stirring position is rolling-reduced by using rolling-reduction roll-pair. Then, the electromagnetic stirring apparatus is disposed at 3-7 m upstream side from the rolling-reduction roll-pair at the uppermost stream side, and the non-solidified steel is electromagnetically stirred so as to become≤6% equiaxed crystal ratio without increasing the equiaxed crystal and also,≥40% thickness of the non-solidified part in the cast slab containing the non-solidified part is rolling-reduced by using the rolling-reduction roll-pair. (2) In the continuous casting method for steel plate, the cast slab is cast with the continuous casting method as the above (1), and the total area ratio of granular or linear semi-macro segregation or macro segregation in the range within 20% at the center part in the plate thickness direction is made to be≤5% to obtain the steel plate excellent in hydrogen induced cracking resistance. COPYRIGHT: (C)2006,JPO&NCIPI
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