一种800 MPa级高强建筑用钢的试验研究

针对当前我国高强建筑用钢的开发,采用Ti-Nb微合金化技术设计试验钢化学成分,通过热膨胀试验确定了试验钢的动态CCT曲线,基于此设计了实验室热轧试验方案,研究了工艺参数对试验钢组织、性能的影响。结果表明:当水冷终冷温度大于610 ℃时,试验钢的显微组织为铁素体+珠光体;当水冷终冷温度小于390 ℃时,试验钢显微组织为少量铁素体+贝氏体;当终轧温度为810 ℃、水冷终冷温度为350 ℃时,试验钢显微组织为少量铁素体+贝氏体,屈服强度为837 MPa,这是细晶强化、相变强化、析出强化共同作用的结果,为800 MPa高强钢筋的研究开发提供了数据支撑和理论指导。

Experimental study on a 800 MPa grade high-strength building steel

In view of the development of the high-strength building steel in our country, the chemical composition of tested steel was designed by Ti-Nb microalloying technology, and the scheme of hot rolling experiment in laboratory was determined by dynamic CCT curve of the tested steel obtained by thermal simulation experiment. The effect of process parameters on microstructure and properties of the tested steel was studied by hot rolling experiment in laboratory. The results show that when the finishing cooling temperature is higher than 610 ℃, the microstructure of the tested steel is composed of ferrite and pearlite. When the finishing cooling temperature is lower than 390 ℃, the microstructure of the tested steel is composed of a small amount of ferrite and bainite. When the finishing rolling temperature is 810 ℃ and the finishing water cooling temperature is 350 ℃, the microstructure of the tested steel is composed of a small amount of ferrite and bainite, and the yield strength is 837 MPa, which is attributed to the combined action of fine grain strengthening, phase transformation strengthening and precipitation strengthening, that provides data support and theory guiding for the research and development of 800 MPa grade high-strength reinforced bar.