STEEL MEMBER FOR SEISMIC RESPONSE CONTROL DAMPER AND METHOD FOR PRODUCING THE SAME

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/mm², 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/mm². 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 Ar₃ 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