| 摘要 |
<p>A steel material having excellent weld HAZ(Heat-Affected Zone) toughness and a manufacturing method of the same are provided to prevent toughness degradation of the HAZ, and reduce amounts of solid solution REM and of solid solution Zr, thereby restricting the change of the HAZ toughness. A steel material having excellent weld heat-affected zone toughness comprises C : 0.01 to 0.2 %, Si : less than 0.5 %, Mn : less than 2.5 %, Ti : less than 0.03 %, N : less than 0.01 %, P : less than 0.02 %, S : less than 0.015 %, Al : less than 0.01 %, REM : 0.0010 to 0.1 %, Zr : 0.001 to 0.05 %, and the remainder Fe, and unavoidable impurities. Inclusions have REM and Zr, which REM is less than 0.0010 %, and Zr is less than 0.0010 %.</p> |
