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采用拉力试验机、金相显微镜、透射电镜、X射线衍射仪、扫描电镜和冲击试验机对富氮钒铌微合金化控冷工艺制备的600MPa级抗震钢筋的力学性能、显微组织、析出相、断口形貌、冲击韧性及时效性进行了研究。结果表明:该钢筋具有良好的强韧性、抗震性及低应变时效性,力学性能优异。该钢的显微组织为铁素体+珠光体+少量细小贝氏体(含量5%~10%),组织配比及形态较好。该钢的铁素体基体、晶界及位错线上析出了大量尺寸2~20nm的细小弥散的V(CN)、Nb(CN)析出相,其析出相数量分别占总钒、总铌量的65%以上,起到了较好的沉淀强化及细化晶粒作用。该钢筋拉伸断口呈韧窝状,韧脆转变温度低于-30℃,具有较好的塑韧性和低温冲击韧性。
The mechanical properties, microstructure and precipitated phase of 600MPa anti-seismic reinforced bar prepared by controlled micro-alloying of vanadium-niobium-niobium with cold tensile testing machine, metallographic microscope, transmission electron microscope, X-ray diffraction, scanning electron microscopy and impact testing machine , Fracture morphology, impact toughness and timeliness were studied. The results show that the rebar has good toughness, shock resistance and low strain timeliness, and has excellent mechanical properties. The microstructure of the steel ferrite + pearlite + a small amount of fine bainite (content of 5% to 10%), the ratio of the tissue and the morphology is better. A large number of V (CN) and Nb (CN) precipitates with a size of 2 ~ 20nm were precipitated on the ferrite matrix, grain boundary and dislocation lines. The amount of precipitated phases accounted for total vanadium and total niobium Of the 65%, played a better precipitation strengthening and grain refinement. The tensile fracture of the reinforced rebar is ductile, the ductile-brittle transition temperature is lower than -30 ° C, and the plastic ductile toughness and the low-temperature impact toughness are good.