空冷弛豫对铌微合金化热轧TRIP钢组织性能的影响  

Effect of air-cooling relaxation on microstructure and mechanical properties of hot-rolled Nb microalloyed TRIP steel

作　　者：郑东升[1] 朱伏先[1] 李艳梅[1] 张明亚[1] 

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《材料热处理学报》2011年第3期73-78,共6页Transactions of Materials and Heat Treatment

基　　金：国家"十一五"科技支撑计划项目(2006BAE03A08)

摘　　要：通过热轧试验研究了轧后空冷弛豫时间对铌微合金化热轧TRIP中厚板组织和力学性能的影响,结合光学显微镜、扫描电镜、透射电镜及XRD分析了弛豫过程各组成相的尺寸、含量变化以及铁素体基体上的位错组态和微合金碳氮化物的析出行为。结果表明,采用820℃终轧并弛豫80～120 s后超快冷的工艺可以得到含有铁素体、贝氏体和残留奥氏体的多相组织,弛豫时间显著影响铁素体晶粒尺寸、铁素体量以及铁素体基体上的位错密度和沉淀析出量。随着弛豫时间的延长,试验钢的屈服强度和抗拉强度呈降低趋势。空冷弛豫80 s时,试验钢的抗拉强度、伸长率和强塑积分别达到820 MPa,37.5%和30750 MPa.%的最大值。Effect of air-cooling relaxation time after finish rolling on microstructure and mechanical properties of hot-rolled Nb microalloyed TRIP steel plate was investigated.The size and content of microconstituent in the steel as well as dislocation configuration and precipitation behavior of microalloying carbonitride in ferrite matrix were analyzed by optical microscopy,SEM,TEM and XRD.The results show that the multiphase microstructure which consists of ferrite,bainite and retained austenite is obtained when the finish rolling temperature of 820 ℃,relaxation time of 80-120 s and subsequent ultra-fast cooling are adopted,and that the relaxation time significantly influences the ferrite grain size,ferrite amount,dislocation density and precipitation amount in the ferrite matrix.The yield and tensile strength decrease with the increase of relaxation time.When the relaxation time is 80 s,tensile strength,total elongation and product of tensile strength and ductility of the steel reach the maximum values,i.e.,820 MPa,37.5% and 30750 MPa.%,respectively.

关 键 词：铌微合金钢 热轧TRIP钢 弛豫 显微组织 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]