【作者】 袁付春； 刘雅政； 周乐育； 李明扬；

【Author】 Yuan Fuchun;Liu Yazheng;Zhou Leyu;Li Mingyang;School of Materials Science and Engineering, University of Science and Technology Beijing;

【机构】 北京科技大学材料科学与工程学院；

【摘要】 本文首先在Gleeble-1500热模拟试验机上进行Nb-Ti复合微合金钢相变规律研究实验,分析冷却速度对实验钢铁素体转变的影响规律。在此基础上进行实验室热轧试制,利用扫描电子显微镜观察实验钢组织,并测量实验钢板力学性能,分析实验钢板铁素体组织形态对力学性能的影响。实验结果表明,随着冷却速度的提高,微合金高强钢中铁素体形态由多边形铁素体变为针状铁素体,高冷速条件下,主要发生针状铁素体转变,针状铁素体组织可以显著提高微合金高强钢的屈服强度。当冷却速度由25~35℃/s提高到60~70℃/s时,实验钢屈服强度提高了82MPa;抗拉强度提高了77MPa。其组织由多边形铁素体+贝氏体的复合组织转变为针状铁素体+贝氏体+少量细小弥散的M/A岛的复合组织,针状铁素体+贝氏体+少量M/A岛的复合组织具有较高的抗拉强度、屈服强度,良好的伸长率及较低的屈强比,有较好的强韧性综合力学性能。更多还原

【Abstract】 The transformation rule during the continuous cooling of Nb-Ti tested steels deformed experiment in Gleeble-1500 thermal simulator were carried out. The effect of cooling rate on the ferrite transformation of tested steel was analyzed. Based on the result of controlled rolling and controlled cooling thermal simulator,the microstructure was observed by the scanning electron microscope(SEM) and the mechanical property of tested steel plate was measured. The effect of microstructure and morphology of ferrite on mechanical property was analyzed. The result of the experiment shows that the ferrite form of microalloy high-strength steel change from the polygon ferrite to the acicular ferrite, as the cooling rate increases. In high cooling rate conditions, acicular ferrite transformation mainly happened. The acicular ferrite is benefit to improve the yield strength. When cooling rate improved from 25~35℃/s to 60~70℃/s, yield strength increased 82 MPa and tensile strength increased 77 MPa. The compound tissue of polygon ferrite +little tiny dispersion bainite translate into the compound tissue of acicular ferrite + bainite + little M/A. The compound tissue has a high strength, high yield strength, good elongation rate and low YS/TS ratio. The steel had good tenacity comprehensive mechanical properties.更多还原