It is superior in fire resistance, shows yield ratio low even at the time of high strain speed deformation, at the same time iterates after the plastic becoming deformed earthquake-proof Characteristic construction steel null of high

摘要

PROBLEM TO BE SOLVED: To provide a high-refractory earthquake-resistant steel material having low YR (≤80%) even if being subjected to deformation at high strain velocity, also having stable and superior toughness even after being subjected to prestrain repeatedly at high strain velocity, excellent in refractoriness, and enabling a design method combining a refractory design with a plastic earthquake- resistant design of a structure in the vicinity of an active fault. ;SOLUTION: This steel material has a composition consisting of, by weight ratio, 0.04-0.18% C, 0.05-0.4% Si, 0.6-1.7% Mn, 0.1-0.6% Mo, 0.005-0.1% V, 0.001-0.06% Al, ≤30ppm N, ≤30ppm O, and the balance Fe with inevitable impurities and satisfying 0.12%≤(Mo+3.5V)%≤0.8% and also has a dual-phase structure of coarse-grained ferrite and bainite.;COPYRIGHT: (C)1997,JPO