The continuously cast slab containing steel B

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PROBLEM TO BE SOLVED : To provide a continuously cast B-containing steel cast metal in which the occurrence of surface cracks is suppressed.SOLUTION : The continuously cast B-containing steel cast metal contains C : 0.050-0.180%, Si : 0.10-0.40%, Mn : 0.5-2.0%, P : 0.020% or less, S : 0.0030% or less, Ti : 0.005-0.030%, Sol. Al : 0.005-0.060%, B : 0.0005-0.0050%, N : 0.0015-0.0070%, and rare earth metals : 0.001-0.050%. The slab further contains at least one of Cu, Cr, Ni, Mo, V, Nb, and Ca in amounts of Cu : 0.1-0.5%, Cr : 0.2-2.0%, Ni : 0.3-2.5%, Mo : 0.1-0.8%, V : 0.01-0.10%, Nb : 0.005-0.050%, and Ca : 0.0005-0.0060%, and the balance comprising Fe and impurities, and contents of Ti, rare earth metals, B, and N satisfy a relationship : ([%Ti]+[%REM])/([%B]+[%N])≥2.5.