| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing steel for welded structure excellent in high temperature strength and low temperature toughness as the many kinds of steel for welded steel structure. SOLUTION: The steel is produced using a cast slab or a cast billet which contains 0.003-0.05% C,≤0.60% Si, 0.6-2.0% Mn,≤0.020% P,≤0.010% S, 0.20-1.5% Cr, 0.005-0.05% Nb,≤0.060% Al, 0.001-0.006% N and if necessary, one or more kinds among the specific quantities of V, Ti, Ni, Cu, B, Mg Ca, REM, and contains substantially no Mo and has≤0.24 P<SB>CM</SB>value. The above cast slab or cast billet is heated to 1,000-1,300°C, and after completion of hot-rolling of the cast slab or cast billet at≥800°C, natural cooling is performed or an accelerated cooling is started from≥750°C and stopped at≤550°C. COPYRIGHT: (C)2009,JPO&INPIT
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