控冷温度对钒铌微合金高强钢筋组织和性能的影响  

Effects of controlled cooling temperature on microstructure and peformance of V-Nb microalloyed high-strength rebars

作　　者：陈伟[1,2] 施哲[1] 陈红[2] 曹建春[3] 赵宇[2] 

机构地区：[1]昆明理工大学冶金与能源工程学院,云南昆明650093 [2]武钢集团昆明钢铁股份有限公司,云南昆明650302 [3]昆明理工大学材料科学与工程学院,云南昆明650093

出　　处：《材料热处理学报》2013年第10期55-61,共7页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51261009);云南省科技计划项目(2009BA008)

摘　　要：针对富氮钒铌微合金化控冷工艺生产的500MPa高强钢筋，利用热模拟试验，通过SEM、硬度试验、TEM及XRD研究了精轧后采用不同控冷温度对钢筋显微组织、晶粒度、硬度及析出相的影响。结果表明，控冷终止温度控制在720～740℃，显微组织为细小块状铁素体＋珠光体＋少量贝氏体（含量6％～15％），组织配比及形态较好，有利于钢筋强度提高和塑韧性的改善；铁素体晶粒度为10．5—11．0级，细晶强化及抗震性能较好；试样维氏硬度为208～213HV，其对应的抗拉强度Rm为700—720MPa，强度富余量适中；铁素体基体、晶界及位错线上形成和分布着尺寸为5～30nm的大量细小弥散的V（CN）、Nb（CN）析出相，析出相的体积分数70％，起到了较好的沉淀强化及细化晶粒作用。In view of 500 MPa grade high-strength rebars V-Nb microalloyed by controlled cooling process in domestic steel plant, the effects of controlled cooling temperature after finishing rolling on microstructure, grain size, hardness and precipitates of the rebars were investigated by thermal simulation, SEM, hardness test, TEM and XRD. The results show that, when controlled cooling temperature is controlled in the range of 720 - 740℃, microstructure of the tested steel consists of ferrite, pearlite and a small amount of bainite （6% - 15% mass factron） , ratio and shape of phases in the microstructure is better, is favorable for improvement of strength, toughness and ductility of the rebars, the size grade of ferrite grain is in the range of 10.5 - 11.0, obvious effect of fine grain strengthening and anti- seismic performance are obtained; Vickers hardness of the tested steel is 208 -213 HV, the corresponding tensile strength（Rm ） increases from 700 MPa to 720 MPa. The size of a lot of small V（CN） and Nb （CN） precipitates is in the range of 5 - 30 nm, which distributes on grain boundary dislocation lines and within ferrite matrix, and the precipitate fraction is 70%. The excellent effect of precipitation strengthening and grain refinement are obtained for the steel by the controlled cooling process.

关 键 词：500MPa高强钢筋 控冷温度 显微组织 硬度 析出相 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TF762[金属学及工艺—金属材料]