Patent ID: 8097096
Filing Date: 2012-01-17
Classification: C21D,C22C

Abstract:
1. A fire resistant steel material excellent in high temperature strength, toughness, and reheating embrittlement resistance characterized by containing, by mass %, C: 0.001% to 0.030%, Si: 0.05% to 0.50%, Mn: 0.4% to 2.0%, Nb: 0.10% to 0.50%, Ti: 0.005% to less than 0.040%, N: 0.0001% to less than 0.0050%, and Al: 0.005% to 0.030%, limiting P: 0.03% or less and S: 0.02% or less, having contents of C, Nb, Ti, and N satisfying C—Nb/7.74≦0 and 3≦Ti/N≦12, and having a balance of Fe and unavoidable impurities, and having a cross-sectional shape of an H-shape comprised of integrally formed flanges and a web, said flanges have a plate thickness of 12 mm or more, and said web has a plate thickness of 7 mm or more.