摘要
随着社会经济的不断发展,建筑行业对于建筑材料强度的要求也越来越高,建筑结构用钢的组织类型也由铁素体/珠光体向铁素体/贝氏体、全贝氏体和多相多尺度亚稳(M~3)组织方向发展。耐火钢以其优异的综合性能和良好的耐火安全性等优点,被广泛应用于高层及大跨度建筑中。对于耐火性能的调控方式也从高成本的高Mo(≥0.40%)加单一元素的微合金化为主的方式向经济型的节Mo(≤0.30%)加Nb、V和Ti等多元复合微合金化方式发展。详细介绍了国内外耐火钢的发展历史、产品种类和应用工程以及提高耐火钢室温强度和耐火性能的理论和技术,对比研究了不同组织和微合金元素的耐火性能的差异。研究表明,多元复合微合金化钢在室温和600℃高温的性能要优于单一元素的微合金化钢的性能,因此提出了多元复合微合金纳米碳化物遇火析出增强高温耐火性能的新思路。针对Q345~Q690不同强度级别耐火钢,形成了差异化的合金与组织设计及其热轧/热处理技术,利用扫描电镜(SEM)观察不同强度级别耐火钢的组织类型,阐明了典型多元复合微合金化耐火钢升温-加载过程中显微组织和力学性能的变化规律。采用透射电镜(TEM)、物理化学相分析和三维原子探针(3DAP)等研究方法观察和统计热轧态、不同热处理态和600℃高温拉伸态析出相的分布、尺寸和数量,探讨了纳米碳化物高温沉淀强化、基体组织高温稳定的耐火机理。研究表明,经过弛豫处理的Q345级别钢板为先共析铁素体+少量贝氏体/珠光体组织,具有较高的细晶和沉淀强化增量;轧后直接进行层流冷却的Q345级别钢板为全贝氏体组织,有着较高的位错和固溶强化增量,600℃拉伸的屈服强度(Yield Strength,YS)仍能达到327 MPa。Q460级别钢板为全贝氏体组织,600℃时组织具有良好的高温稳定性,随着在600℃时保温时间的延长,直径小于1
With the development of social economy,the construction industry has put forward higher requirements for the strength of building materials.The microstructure of construction steel for building has developed from ferrite/pearlite to ferrite/bainite,bainite,multiphase and multiscale metastable(M~3).Fire-resistant steel is widely used in high-rise and large-span buildings due to its excellent comprehensive properties and good fire resistant safety.The control of fire resistance properties has also evolved from high-cost high Mo(≥0.40%)plus single microalloyed mode to economical saving Mo(≤0.30%)plus Nb,V and Ti and other composite multi-microalloyed methods.The development history,product types and application engineering of fire resistance steel at home and abroad,as well as theories and technologies to improve the strength and fire resistance of fire-resistance steel were introduced in detail.The differences in the fire resistance properties of different microstructures and microalloy elements were comparatively studied.The research shows that the room temperature and 600℃properties of the composite multi-microalloyed steel are better than that of the single microalloyed steel,and puts forward a new idea of multi-microalloyed nano-carbide precipitated in fire to enhance the fire resistance properties.For Q345-Q690 fire-resistance steel,the differentiated alloy and microstructure design and its hot rolling/heat treatment technology were formed.The microstructure types of different strength grades of fire-resistance steels were observed by scanning electron microscopy(SEM),and the microstructure and mechanical properties of typical multi-microalloyed fire-resistance steel during reheating-loading process were clarified.The distribution,size and quantity of precipitated phases in hot-rolled state,heat-treated state and 600℃tensile state were observed and counted by transmission electron microscopy(TEM),physical and chemical phase analysis and three-dimensional atom probe(3 DAP).The fire resistance mechanism
作者
王鑫
李昭东
张可
王文涛
杨忠民
雍岐龙
Xin Wang;Zhaodong Li;Ke Zhang;Wentao Wang;Zhongmin Yang;Qilong Yong(Department of Structural Steels,Central Iron and Steel Research Institute,Beijing 100081,China;Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China;School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243032,China)
出处
《钢结构（中英文）》
2021年第3期1-11,共11页
Steel Construction（Chinese & English）
基金
国家重点研发计划(2017YFB0304700,2017YFB0304702)
国家自然科学基金项目(51704008)。
关键词
微合金化
耐火钢
纳米析出
耐火机制
microalloyed
fire-resistant steel
nano-precipitation
fire resistant mechanism
