摘要
通过热模拟试验研究了冷却速率和控冷终止温度对V-N微合金化600 MPa高强钢筋组织和性能的影响。由动态CCT（Continuous Cooling Transformation）曲线和组织分析可知,实验钢筋在冷速为0.5~1℃/s时得到的室温组织为块状铁素体和珠光体;当冷速达到3℃/s时有少量的贝氏体（含量为5%）出现;当冷速在8℃/s以上时,实验钢筋的显微组织为少量的晶界铁素体＋贝氏体＋马氏体。因此,为了得到具有高强度和良好塑性的显微组织,轧后冷却速率应控制在0.5~3℃/s。此外,控冷终止温度应控制在600~625℃,显微组织为细小的块状铁素体＋珠光体＋少量的贝氏体（含量为0~8%）,铁素体的晶粒尺寸为4.5~5.2μm,试样维氏硬度为263~274 HV,其对应的抗拉强度为875~908 MPa,有足够的强度余量。
Effect of cooling rate（ CR） and finish cooling temperature（ FCT） on microstructure and mechanical properties of a V-N microalloyed 600 MPa high strength rebar steel was investigated by thermal simulation tests. From the dynamic continuous cooling transformation（ CCT） diagram and the microstructure analysis,it is found that the microstructure is composed of polygonal ferrite and pearlite when the cooling rate is in the range of 0. 5-1 ℃ / s; the bainite（ the volume fraction is about 5%） is observed at the cooling rate of 3 ℃ / s; the microstructure consists of grain boundary ferrite,bainite and martensite when the cooling rate is above 8 ℃ / s. Based on the experimental results,the appropriate cooling rate of 0. 5-3 ℃ / s is recommended to obtain a good combination of strength and ductility,and the finish cooling temperature should be controlled in the range of 600-625 ℃,in which the microstructure is composed of refined ferrite grain,pearlite and bainite（ the volume fraction is about 0-8%） and the size of ferrite grain is about 4. 5-5. 2 μm. Under the processing conditions,the hardness of the experimental steel is in the range of 263-274 HV and the corresponding tensile strength is875-908 MPa.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2016年第1期93-98,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51374018
51174020)
关键词
高强钢筋
冷却速率
控冷终止温度
显微组织
力学性能
grade high strength rebar
cooling rate
finish cooling temperature
microstructure
mechanical property
