| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel member having excellent HAZ toughness even in the case high heat input welding is performed, and to provide a method for producing the same. SOLUTION: The steel member has a composition particularly comprising Zr, REM and/or Ca. Also, (a) the steel member includes the oxides of Zr, REM and/or Ca, (b), when the composition of all the oxides included in the steel member is measured and is expressed in terms of independent oxides, ZrO<SB>2</SB>: 5 to 50%, the oxide of REM: 10 to 50% and/or CaO: 5 to 50% are satisfied, and further, (c), among all the oxides included in the steel member, the number of the oxides with an equivalent circular diameter of 0.1 to 2.0μm is≥120 pieces per mm<SP>2</SP>and the number of the oxides with an equivalent circular diameter of >5.0μm is≤5 pieces per mm<SP>2</SP>. COPYRIGHT: (C)2009,JPO&INPIT
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