MANUFACTURE OF 400N/MM2 CLASS FIRE RESISTANT STEEL FOR BUILDING CONSTRUCTION HAVING LOW YIELD RATIO

摘要

PURPOSE: To manufacture a fire resistant steel for building construction having high proof stress and low yield ratio at a high temp. ;CONSTITUTION: A slab contg. 0.07 to 0.15% C, 0.05 to 0.60% Si, 0.30 to 1.50% Mn, 0.10 to 0.40% Mo, 0.005 to 0.060% Nb and the balance Fe with inevitable impurities is heated to ≥1050°C and is rolled at the temp. of 900 to 1000°C to manufacture a 400N/mm² class fire resistant steel for building construction having low yield ratio and ≥157N/mm² proof stress. Since the steel has high proof stress at 600°C, good weldability and also low yield ratio, fire-proofing covering required heretofore can drastically be decreased or reduced.;COPYRIGHT: (C)1993,JPO&Japio