回火温度对热轧Ti-Mo-V钢第二相析出行为的影响  

Effect of tempering temperature on the second phase precipitation behavior of hot-rolled Ti-Mo-V steel

作　　者：马凯 杨庚蔚[1] 付至祥 韩汝洋 徐耀文[1] 许德明[1] MA Kai;YANG Gengwei;FU Zhixiang;HAN Ruyang;XU Yaowen;XU Deming(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081

出　　处：《钢铁》2025年第2期84-93,共10页Iron and Steel

基　　金：国家重点研发计划资助项目(2021YFB3702402);国家自然科学基金项目资助(52204398);湖北省自然科学基金资助项目(2023AFA062)。

摘　　要：热轧带钢中微合金元素析出不完全的情况普遍存在,回火处理可以使钢中固溶的微合金元素进一步析出,有助于其力学性能的提升。以热轧Ti-Mo-V微合金化超高强钢为研究对象,利用扫描电子显微镜、透射电子显微镜与维氏硬度计等,系统研究了回火温度对钢中微合金第二相析出行为的影响。研究结果表明,与热轧态相比,当回火温度为550~700℃时,试验钢中铁素体晶粒变化不明显。在热轧阶段未完全析出的微合金元素在回火过程中会逐渐析出,析出相为富V的(Ti,Mo,V)C粒子。同时,随着回火温度升高,析出相与基体之间的错配度下降、比界面能降低,且原子扩散速度明显加快,有利于(Ti,Mo,V)C在基体中析出。试验钢中(Ti,Mo,V)C粒子的体积分数和平均粒径均随着回火温度升高逐渐增大,且(Ti,Mo,V)C粒子中V原子数分数增加,晶格常数减小。当回火温度为700℃时,试验钢中析出的(Ti,Mo,V)C粒子体积分数达到0.609%,平均粒径约为8.39 nm,V原子数分数为51.9%,晶格常数为0.436 nm。另外,试验钢中微合金第二相提供的沉淀强化增量随着回火温度的升高呈现出先增大后减小的变化趋势。当回火温度由550℃上升至650℃时,试验钢中的沉淀强化增量由286.6 MPa升高至327.3 MPa,显微硬度达到峰值,约为282.1HV。当回火温度进一步上升至700℃时,(Ti,Mo,V)C粒子发生明显粗化,其产生的沉淀强化增量减小至282.2 MPa,且基体组织软化进一步加剧,试验钢的显微硬度下降至261.1HV。热轧Ti-Mo-V微合金化超高强钢在650℃下回火1 h后,析出强化得到大幅提升,力学性能显著提升。It is common that microalloying elements have not been completely precipitated in hot-rolled strip steel,and tempering treatment can make the solid-solved microalloying elements in the steel precipitate in the matrix,thus enhancing its mechanical properties.The effect of tempering temperature on precipitation behavior of microalloyed second phase of hot-rolled Ti-Mo-V microalloyed ultra-high-strength steel was studied by scanning electron microscope,transmission electron microscope and Vickers hardness tester.The results show that when tempering temperature is 550-700℃,the ferrite grain changes in the tested steel are not obvious compared with the hot-rolled tested steel.The microalloyed elements that are not completely precipitated in the hot rolling stage are gradually precipitated during the tempering process,and the precipitated phase is V-rich(Ti,Mo,V)C particles.At the same time,with the increase of tempering temperature,the lattice mismatch between the precipitation and the matrix decreases,the specific interfacial energy decreases,and the atomic diffusion rate is significantly accelerated,which favors the precipitation of(Ti,Mo,V)C in the matrix.The volume fraction and the average particle size of(Ti,Mo,V)C particles in the tested steel gradually increase,and the proportion of V atoms in(Ti,Mo,V)C particles increases and the lattice constant decreases.When tempering temperature is 700℃,the precipitation volume fraction of(Ti,Mo,V)C particles in the tested steel reaches 0.609%,the average particle size is about 8.39 nm,the atomic fraction of V is 51.9%,and the lattice constant is 0.436 nm.In addition,precipitation strengthening increment provided by the microalloyed second phase of the tested steel exhibits a tendency of increasing and then decreasing with the increase of tempering temperature.When the tempering temperature increases from 550℃to 650℃,the precipitation strengthening increment in the tested steel increases from 286.6 MPa to 327.3 MPa,and the microhardness reached a peak of about 282.

关 键 词：Ti-Mo-V微合金化 超高强钢 回火温度 析出行为 沉淀强化 第二相 力学性能 热轧 控轧控冷 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.5[金属学及工艺—金属材料]