| 摘要 |
PURPOSE:To inhibit the formation of abnormal grains by heating by hot rolling a steel with high tensile strength for high heat input welding contg. specified amounts of C, Si, Mn, Al and a component for increasing the strength and toughness, and a restricted amount of N after adjusting the composition with REM and Ti. CONSTITUTION:A slab of a steel with high tensile strength for high heat input welding having a composition contg., by weight, 0.01-0.15% C, 0.05-0.6% Si, 0.5-2% Mn and 0.01-0.8% A as essential components, one or more among 0.005-0.1% Nb, 0.005-0.15% V, 0.1-2% Ni, 0.1-1% Cu, 0.1-1% Cr, 0.05- 0.5% Mo and 0.0005-0.002% B, and 0.001-0.007% N is hot rolled at (the Ac3 point -30 deg.C)-1,150 deg.C after adjusting the composition by adding 0.005-0.025% Ti and 0.002-0.01% REM. One or more among said Nb, V, Ni, Cu, Cr, Mo and B are contained in accordance with the required strength and toughness. |
