轧制工艺对V-Nb微合金化HRB600E钢筋组织及性能的影响

采用了高温共聚焦显微镜、高分辨透射电镜和光学显微镜等系统研究了轧制工艺对V-Nb微合金化HRB600E钢筋的组织、力学性能及析出行为的影响。结果表明,试验钢奥氏体晶粒尺寸随加热温度升高、保温时间延长而增大。轧制温度提升60 ℃后,试验钢组织中珠光体团比例及尺寸分别增加10.9%和5.1 μm,导致抗拉强度增加30~40 MPa,断后伸长率降低3%~5%;同时,试验钢中V(C, N)析出数量减少而VNb(C, N)数量增加,整体析出粒子数量减少但其等效圆直径增大。不同轧制工艺析出强化效果差别不大,整体中的相变强化效果大于析出强化。

Effect of rolling process on microstructure and properties of V-Nb micro-alloyed HRB600 E steel rebar

Effect of rolling process on microstructure, mechanical properties and precipitation of V-Nb micro-alloyed HRB600E steel rebar was researched by means of confocal laser scanning high-temperature microscope, HR-TEM and OM systematically. The results show that with the increase of heating temperature and holding time, austenite grain size of the tested steel rebar increases. When the rolling temperature increases 60 ℃, the proportion and size of pearlite colony in the tested steel rebar increase 10.9% and 5.1 μm respectively, and the tensile strength increases 30-40 MPa, while the elongation decreases 3%-5%. Meanwhile, the precipitation amount of V(C, N) decreases while the amount of VNb(C, N) increases, the precipitation amount of the whole precipitated particles decreases but their equivalent circular diameter increases. The precipitation strengthening effect of various rolling processes has little difference, the strengthening effect of phase transition in the tested steel rebar is superior to the precipitation in the whole.