Continuous cast slab

Abstract

Provided is a continuously cast slab that prevents cracking during a cooling process therefor even if such a slab is a high-alloy slab with low toughness. Specifically, provided is a continuously cast slab for high-strength steel with features such that the average prior austenite grain size at a position 10 mm from the surface layer of the continuously cast slab is in the range of 100 µm to 0.5 mm; and in the microstructure of the slab, the area ratio of ferrite is 10% or more, the area ratio of pearlite is 10% or more, and the area ratio of bainite is in the range of 1% to 30%. The continuously cast slab preferably contains, in mass%, C: 0.10 to 0.40%, Si: 0.10 to 2.50%, and Mn: 1.00 to 5.00%.

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