采用Nb微合金化和控冷工艺开发HRB500抗震钢筋，通过金相显微镜、扫描电镜、透射电镜、X线衍射仪及拉力试验机对钢筋取样金相显微组织、析出相、力学性能及强韧化机理进行分析研究。研究结果表明：采用Nb微合金化和控轧控冷工艺生产HRB500抗震钢筋，最主要的强化机制为细晶强化，其对强度贡献超过40％；采用该工艺，钢筋铁素体晶粒度达11.0级以上，晶粒细化效果明显;铁素体基体、晶界及位错线上形成和分布着尺寸为10～20 nm的大量细小弥散的Nb(CN)析出相，起到了较好的沉淀强化及细化晶粒作用；晶粒细化使冲击转折温度下降150℃，使钢筋在获得较高强度的同时，仍具有较好的塑韧性。%Development of HRB500 anti-seismic rebars by Nb microalloyed and controlled cooling process was introduced. The microstructure, educt, mechanical properties, strengthening and toughening mechanism were researched and analyzed by means of metallographic microscopy, scanning electron microcopy, transmission electron microscopy, X-ray diffraction apparatus and tensile testing machine. The results show that fine-grain strengthening is the primary mechanism of strengthening and toughening for HRBSOO rebars produced by Nb microalloyed and controlled cooling process, contribution of its strength is more than 40% of total strength; ferrite grain grade of rebars is more than 11.0, obvious effect of grain refinement is obtained. A large number of small and diffuse of Nb(CN) educts sized 10-20 nm are formed and distributed on ferrite matrix, grain boundary and dislocation lines, good effect of precipitation strengthening and grain refinement are received; impact transition of temperature reduces by 150 ℃ by grain refinement, and higher strength for rebars is acquired. Meanwhile, rebars still have good plasticity and toughness.
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