| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-tension structural steel having a low yield ratio, a low production cost and an excellent refractoriness at elevated temperature and an excellent weldability, which satisfies the specifications for SN400 or SN490 defined by JIS, ensures a strength at elevated temperature satisfying: (yield strength at 650°C)/(yield strength at ordinary temperature)≥0.5 and (yield strength at 700°C)/(yield strength at ordinary temperature)≥0.4, and shows an excellent weldability (Y crack stopping temperature of≤0°C), and its manufacturing process. SOLUTION: The steel contains 0.01-0.13 mass% C, 0.01-0.5 mass% Si, 0.01-0.5 mass% Mn, 0.3-1.3 mass% Mo, 0.03-0.1 mass% Ti, 0.003-0.07 mass% sol.Al and≤0.01% N, wherein the remainder comprises Fe and unavoidable impurities. COPYRIGHT: (C)2003,JPO
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