【作者】 许立雄； 武会宾； 汤启波； 王鑫田； 牛刚； 顾洋； 于新攀；

【Author】 Xu Lixiong;Wu Huibin;Tang Qibo;Wang Xintian;Niu Gang;Gu Yang;Yu Xinpan;Collaborative Innovation Center of Steel Technology of USTB;National Engineering Research Center of Advanced Rolling of USTB;

【机构】 北京科技大学钢铁共性技术协同创新中心； 北京科技大学高效轧制国家工程研究中心；

【摘要】 本文基于日钢的ESP(endless strip processing)生产线,介绍了无头轧制过程中卷取温度对Nb-Ti微合金钢的显微组织、析出行为及力学性能的影响规律。当卷取温度为560℃时,卷取前63.4%的Nb、44.0%的Ti和74.8%的C仍处于固溶状态;当卷取温度从600℃降低到560℃,室温组织中针状铁素体明显增多且平均晶粒直径由2.01 nm减小到1.29 nm,组织强化使钢的屈服强度和抗拉强度分别增加了22 MPa和20 MPa。当卷取温度由600℃升高到640℃,析出物质量分数由0.083%增加到0.110%,且18 nm以下的小尺寸析出物的质量百分比由12.2%增加到14.7%,此时析出强化使屈服强度和抗拉强度分别增加了35 MPa和42 MPa。因此,当卷取温度由640℃降低到560℃时,试验钢的强度先降低后升高,而低温转变组织的增多使钢的延伸率由18.9%降低到14.1%。更多还原

【Abstract】 This paper presents our latest results on how coiling temperature affects the microstructure, precipitation behavior, and mechanical properties of a Nb-Ti microalloyed steel, which was produced on endless strip processing(ESP) line in Rizhao steel and coiled at different temperatures. The results reveal that 63.4 % of Nb, 44.0 % of Ti, and 74.8 % of C were still in solution before coiling at the coiling temperature of 560℃. As the coiling temperatures decreased from 600℃ to 560℃, the proportion of acicular ferrites(AF) increased and the average grain size was refined from 2.01 nm to 1.29 nm, then the yield strength and tensile strength of the tested steel increased by 22 MPa and 20 MPa under the effect of microstructural strengthening. As the coiling temperatures increased from 600℃ to 640℃, the mass fraction of the precipitates increased from 0.083 % to 0.110 % and the percentage of fine precipitates(smaller than 18 nm) increased from 12.2 % to 14.7 %, the intense precipitation strengthening increased the yield strength and tensile strength by 35 MPa and 42 MPa respectively. In consequence, as the coiling temperatures decreased from 640℃ to 560℃, the strength of the tested steel decreased first and then increased, while the elongation of steel decreased monotonously from 18.9 % to 14.1 % due to the increasing proportion of AF.更多还原