オンライン熱処理プロセスによる780N/mm²級鋼の低降伏比化とその建築柱部材としての局部座屈性能

抄録

780N/mm² Grade strength steel plates designed for earthquake-proof buildings have been developed. They provide high strength, low yield ratio, weldability and excellent toughness in welded joints. Key technology to obtain an excellent combination of mechanical properties is microstructural control of M-A (Martensite-Austenite constituent) and granular bainitic ferrite dual-phase structure through HOP (Heat-treatment On-line Process) immediately after an accelerated cooling in TMCP(Thermo-Mechanical Control Process). The developed steel plates have shown satisfactory performance for local buckling.