Microstructures and properties of low-alloy fire resistant steel

[摘要] Microstructures and properties of weldable quality low-alloy fire resistant structural steels (YS: 287â€�??415 MPa) and TMT rebar (YS: 624 MPa) have been investigated. The study showed that it is possible to obtain two-thirds of room temperature yield stress at 600°C with 0.20â€�??0.25% Mo and 0.30â€�??0.55% Cr in low carbon hot rolled structural steel. Microalloying the Crâ€�?�Mo steel by niobium or vanadium singly or in combination resulted in higher guaranteed elevated temperature yield stress (250â€�??280 MPa). The final rolling temperature should be maintained above austenite recrystallization stop temperature (∼ 900° C) to minimize dislocation hardening. In a quenched and self-tempered 600 MPa class TMT reinforcement bar steel (YS: 624 MPa), low chromium (0.55%) addition produced the requisite yield stress at 600°C. The low-alloy fire resistant steel will have superior thermal conductivity up to 600°C (> 30 W/m.k) compared to more concentrated alloys.

[学科分类] 材料工程

[关键词] Fire resistant steel;thermomechanical processing;microstructure;strength;thermal conductivity.