| 摘要 |
A method for manufacturing steel products for welding which can allow a heat affected zone to have a high toughness although the steel products are applied to high heat input welding by distributing precipitates finely and uniformly through nitriding treatment, and a welding structure manufactured by the high heat input welding such that the heat affected zone has a high toughness are provided. A manufacturing method of a steel product for welding comprises the steps of: manufacturing a slab comprising, by weight percent, 0.001 to 0.03% of C, 0.01 to 0.5% of Si, 1.0 to 3.0% of Mn, 0.005 to 0.2% of Nb, 0.005 to 0.2% of Ti, 0.005 to 0.1% of Al, 0.0005 to 0.01% of B, 0.005% or less of N, 0.03% or less of P, 0.03% or less of S, 0.005% or less of O, V, and the balance of Fe and other inevitable impurities; heating the slab at a temperature of 1100 to 1250 deg.C for 120 to 300 minutes, thereby nitriding the slab such that conditions of N:0.008 to 0.03% by weight percent, 1.2<=Ti/N<=2.5, 2<=N/B<=20, 3<=Al/N<=7, 3<=Nb/N<=10, 0.5<=V/N<=7, and 7<=(Ti+2Al+4B+Nb+V)/N<=21 are satisfied; and rolling the nitrided slab.
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