| 摘要 |
PROBLEM TO BE SOLVED: To provide a high tensile strength steel material for a hydraulic pressure iron pipe having excellent weld zone toughness, further free from the generation of weld cracking even if welding is performed in a preheating-free state under a high temperature-high humidity environment, and is further friendly to natural environment. SOLUTION: The high tensile strength steel material for the hydraulic pressure iron pipe has a chemical composition containing 0.04 to 0.09% C, 0.05 to 0.6% Si, 1.0 to 1.8% Mn,≤0.02% P,≤0.01% S, <0.005% Nb, 0.002 to 0.07% Al, 0.001 to 0.005% N, and the balance Fe with impurities, and produced by being subjected to hot working after heating to a temperature of 850 to <1,000°C. The steel material may have a chemical composition comprising one or more kinds of elements selected from Cu, Ni, Cr, Mo, V, Ti, B, Ca, Mg and rare earth metals. COPYRIGHT: (C)2010,JPO&INPIT
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