| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing Ni-containing shape steel with a flange thickness of <20 mm which is surely provided with excellent strength and low-temperature toughness even when the number of heat treatments is reduced, and a range of temperature control during the heat treatment is widened. SOLUTION: Steel having a composition consisting of, by mass, 0.01-0.05% C, 0.1-0.5% Si, 0.3-0.7% Mn,≤0.010% P,≤0.010% S, 0.05-0.3% Mo and 7.5-10.5% Ni, and the balance Fe with inevitable impurities is heated at≤1,350°C, subjected to hot rolling at a finish temperature of≥800°C, and natural-cooled thereafter. The steel is further subjected to heat treatment at the temperature range of≥780°C and≤930°C for≤30 minutes of the soaking retention time, and natural-cooled. Thereafter, the steel is further subjected to heat treatment in the temperature range of≥650°C and≤725°C for≤30 minutes of the soaking retention time to obtain a shape steel with a flange thickness of <20 mm. COPYRIGHT: (C)2004,JPO&NCIPI
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