对高强建筑用钢进行控轧控冷处理，研究终冷温度（350~650℃）对该钢显微组织与室温拉伸性能的影响。结果表明：在终冷温度为650，550℃下控轧控冷后，试验钢的显微组织都为贝氏体铁素体+马氏体-奥氏体（M-A）岛；当终冷温度为450℃时，组织仍为贝氏体铁素体+M-A岛，但是M-A岛的含量比终冷温度为650，550℃时的低；当终冷温度为400，350℃时，组织主要为板条状贝氏体铁素体，局部板条间分布着少量薄膜状M-A岛；试验钢的屈服强度、抗拉强度和屈强比均随着终冷温度的降低而升高，而在终冷温度为350，450，550℃时的断后伸长率均大于16%；终冷温度为450℃时，试验钢的拉伸性能符合780 MPa级高强低屈强比建筑用钢的要求，此时贝氏体铁素体组织中弥散分布着细小、圆整度较高的M-A岛，使得试验钢具有高的强塑性和低的屈强比。

A high strength building steel was treated by controlled rolling and cooling process, and the effect of final cooling temperature (350-650 ℃) on the microstructure and tensile properties at room temperature of the steel was studied. The results show that the microstructure of the test steel after controlled rolling and cooling at final cooling temperature of 650 or 550 ℃ was bainite ferrite+martensite-austenite (M-A) island; the microstructure at final cooling temperature of 450 ℃ were still bainite ferrite+M-A island, but the content of M-A island was lower than that at final cooling temperature of 650 or 550 ℃; when the final cooling temperature was 350 ℃, the microstructure was mainly lath bainite ferrite, and a small amount of film-like M-A island distributed among local laths. The yield strength, tensile strength and yield ratio of the test steel increased with decreasing final cooling temperature, while the percentage elongation after fracture exceeded 16% at the final cooling temperature of 350 ℃ or 450 ℃ or 550 ℃. The tensile properties of the test steel met the requirements of 780 MPa grade high strength low yield ratio building steel when the final cooling temperature was 450 ℃; at this time the fine and round M-A island dispersed in the bainite ferrite, which was helpful to obtain high strength and plasticity and low yield ratio of the test steel.