铌微合金对1GPa级热轧双相钢组织及性能影响  

Effect of niobium microalloying on microstructure and properties of 1 GPa hot-rolled dual-phase steel

作　　者：王睿 董思月 付培茂 张永青 于志强 闫志杰 WANG Rui;DONG Siyue;FU Peimao;ZHANG Yongqing;YU Zhiqiang;YAN Zhijie(School of Materials Science and Engineering,Shanxi Key Laboratory of Advanced Metal Materials for Special Environments,North University of China,Taiyuan 030051,Shanxi,China;Technology Center,Shanxi Taigang Stainless Steel Ltd.,Taiyuan 030003,Shanxi,China;CITIC-CBMM Microalloying Technology Center,CITIC Metals Co.,Ltd.,Beijing 100004,China)

机构地区：[1]中北大学材料科学与工程学院,特殊环境先进金属材料山西省重点实验室,山西太原030051 [2]山西太钢不锈钢股份有限公司技术中心,山西太原030003 [3]中信金属有限公司中信微合金化技术中心,北京100004

出　　处：《钢铁研究学报》2024年第4期520-528,共9页Journal of Iron and Steel Research

基　　金：中信金属-CBMM铌技术推广项目(M1530);国家自然科学基金资助项目(51904278);中央引导地方科技发展专项资助项目(YDZJSX2021C007,YDZX20191400004587);山西省重点研发资助项目(20210205020201004,202202050201015);山西省基础研究资助项目(20210302123218)。

摘　　要：为了研究微合金元素铌对热轧双相钢组织和性能的影响,采用相同的工艺制备了含铌和不含铌2种热轧双相钢。通过光学显微镜(OM)、透射电镜(TEM)、X射线衍射仪(XRD)及电子背散射衍射(EBSD)等方法表征了组织变化规律,并分析了铌对双相钢力学性能影响及试验钢的强化机制。结果表明:2种双相钢显微组织均为铁素体和马氏体,铌钢中马氏体体积分数更高;由于铌抑制动态再结晶,无铌钢晶粒以等轴状为主,而铌钢晶粒更细,晶粒呈长条状。铌钢的抗拉强度为1306 MPa,屈服强度为1269 MPa,硬度为40HRC,冲击功为66.5 J,伸长率为12%。位错强化是试验钢的主要强化机制,占总强度40%以上,铌微合金使得试验钢析出强化增量从69 MPa(7%)增加到277 MPa(22%)、位错强化增量从480 MPa(51%)增加到539 MPa(42%)和细晶强化增量从143 MPa(15%)增加到219 MPa(17%),从而导致铌钢强度增高。To investigate the effect of microalloying element niobium on the microstructure and properties of hot-rolled dual-phase steel,two types of hot-rolled dual-phase steels with and without niobium were prepared by the same process.The microstructures of the DP steel were characterized by OM,TEM,XRD and EBSD,and the strengthening mechanisms were analyzed according to the effect of niobium on the mechanical properties of the DP steels.The results show that the microstructures in the two steels are composed of ferrite and martensite,with a higher volume fraction of martensite in niobium steel;the grains in niobium-free steel are mainly equiaxed,while niobium steel has finer and elongated grains,which is attributed to the inhibition of dynamic recrystallization by niobium.In addition,the niobium steel exhibits a tensile strength of 1306 MPa,a yield strength of 1269 MPa,an elongation of 12%,an impact energy of 66.5 J,and a hardness of 40HRC.Dislocation strengthening is the main strengthening mechanism of test steel,accounting for more than 40%of the total strength.Niobium microalloying increased the precipitation strengthening increment from 69 MPa(7%)to 277 MPa(22%),the dislocation strengthening increment from 480 MPa(51%)to 539 MPa(42%)and the grain refinement strengthening increment from 143 MPa(15%)to 219 MPa(17%).Thus,a higher strength is obtained in niobium steel.

关 键 词：热轧双相钢 铌微合金 控轧控冷 位错密度 强化机制 

分 类 号：TG142.1[一般工业技术—材料科学与工程]