| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel member for a seismic response control damper which has a reduced difference in LC (Longitudinal-Crosswise) directions and has a yield point of 205 to 245 N/mm<SP>2</SP>, and to provide a method for producing the same at a low cost. SOLUTION: The steel member for a seismic response control damper comprises, by mass, 0.04 to 0.11% C,≤0.4% Si, 0.1 to 0.5% Mn and≤0.05% Al, and the balance Fe with impurities, has a metallic structure in which a polygonal ferrite grain structure occupies≥90%, and the grain size number thereof is 5.0 to 8.5, and has a yield point of 205 to 245 N/mm<SP>2</SP>. In the method for producing the steel member for a seismic response control damper, steel is hot-rolled at a heating temperature of 1,000 to 1,160°C so as to be finished at a surface temperature of an Ar<SB>3</SB>point-100°C or higher, and (1) is allowed to cool as it, or, after that, (2) is further heated at 900 to 920°C and is allowed to cool, or (3) is heated at 900 to 920°C, is thereafter water-cooled, is next reheated to≤750°C and is allowed to cool. COPYRIGHT: (C)2004,JPO
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