| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel having excellent toughness in the weld heat-affected zone, and to provide a manufacturing method therefor. SOLUTION: The steel has a composition comprising, by mass, 0.01 to 0.2% C,≤0.5% (excluding 0%) Si,≤2.5% (excluding 0%) Mn and≤0.01% (excluding 0%) N, satisfying≤0.02% (including 0%) P,≤0.015% (including 0%) S and≤0.01% (including 0%) Al, further comprising 0.001 to 0.1% rare earth metals and/or 0.0003 to 0.02% Ca, and 0.001 to 0.05% Zr, respectively, and also comprising the oxide of rare earth metals and/or Cao, and ZrO<SB>2</SB>. COPYRIGHT: (C)2007,JPO&INPIT
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