一种460MPa级抗震耐火建筑钢及其制备方法,属于建筑钢领域。其化学成分为：C：0.03～0.08％,Mn：1.0～1.8％,Si：0.1～0.5％,Cr：0.2～0.7％,Mo：0.1～0.3％,Ti：0.05～0.12％,V：0.04～0.12％,Nb：0.01～0.06％,Al：0.01～0.05％,P:≤0.008％,S：≤0.002％,余为铁和不可避免的微量的化学元素。采用常规真空冶炼并浇铸成坯；对铸坯进行加热并常规保温；粗轧并控制温度；精轧并控制结束温度；自然冷却至一定温度；水冷至室温。通过控轧控冷的方式,得到晶粒细小的马氏体/贝氏体和铁素体双相组织。本发明通过TMCP状态交货,无需复杂热处理工艺,具有较宽的工艺窗口,屈服强度≥460MPa,抗拉强度670～800MPa,断后延伸率≥26％,#40℃KV2≥250J以及屈强比﹤0.75,可广泛应用于高层、超高层同时要求高强度及抗震、耐火等要求的建筑钢。

This invention is the production process of 460 MPa anti-seismic, fire-resistant building steels. This material’s chemical composition is: C: 0.03~0.08%, Mn: 1.0~1.8%, Si: 0.1~0.5%, Cr: 0.2~0.7%, Mo: 0.1~0.3%, Ti: 0.05~0.12%, V: 0.04~0.12%, Nb: 0.01~0.06%, Al: 0.01~0.05%, P: ≤ 0.008%, S: ≤ 0.002%, the remainder is iron and inevitable traces chemical element. The process is listed below: 1, using conventional vacuum smelting and casting into billets; 2, heating the cast billets and heat preservation; 3, roughing and controlling the temperature; 4, finishing and controlling the temperature at the end; 5, free cooling to a certain temperature; 6, water colling to room temperature. Through controlled rolling and controlled cooling, a fine-grained martensite/bainite and ferrite dual-phase microstructure. The steel invented in this project is delivered in TMCP state without no more complicated heat treatment, while shows excellent mechanical properties: yield strength ≥ 460 MPa, tensile strength 670~800 MPa, elongation after fracture ≥ 26%, -40 ℃ KV2≥250J, yield ratio < 0.75. This steel is widely used in high-rise building, superhigh-rise building and satisfy high strength, anti-seismic, fire resistance at the same time.