| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing steel small in the variation of the material in the thickness direction and also excellent in the toughness of the welding heat-affected zone. SOLUTION: As to this method for producing steel, a steel stock, which contains, by weight, 0.01 to 0.03% C, 0.05 to 0.10% Nb, 0.0003 to 0.0050% B and 0.005 to 0.050% Ti, in which the ratio of the Ti content and Al content, i.e., Ti/Al satisfies >=5.0, moreover contains one or two kinds of Ca and rear earth metals, and in which oxide inclusions having an inclusion compsn. composed of, by weight, 20 to 90% Ti oxide, <=70% Al2O3, one or two kinds of Ca oxide and REM oxide by 5 to 50% in total and <=15% MnO are dispersed, is heated to the temp. range of 950 to 1,250 deg.C and is thereafter subjected to hot rolling in which the cumulative draft in the temp. region of <=950 deg.C is controlled to >=20%, and the rolling finishing temp. is controlled to >=800 deg.C.
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