Ti-V-Mo微合金化22MnB5钢中析出相及其强化作用  

Precipitates and their strengthening in Ti-V-Mo microalloyed 22MnB5 steel

作　　者：韩荣 刘洪喜[1] 尉文超 王毛球[2] 时捷[2] HAN Rong;LIU Hong-xi;YU Wen-chao;WANG Mao-qiu;SHI Jie(Faculty of Material Science and Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Institute for Special Steels,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]钢铁研究总院特殊钢研究所,北京100081

出　　处：《钢铁》2022年第2期127-138,共12页Iron and Steel

摘　　要：使用温成形替代热成形可以避免热成形过程中表面氧化等问题,但热成形常用22MnB5钢在高温回火后出现明显的软化现象。而通过向钢中添加Ti、V、Mo等微合金元素可以在钢中形成细小的析出相以及细化晶粒,起到提高强度的作用,从而可以解决该问题。因此,通过在22MnB5钢中添加Ti、V、Mo微合金元素,利用OM(光学显微镜)、FE-SEM(场发射扫描电子显微镜)、EBSD(电子背散射衍射)、TEM(透射电子显微镜)、XRD(X射线衍射分析)、EDS(能谱仪)及物理化学相分析法等,研究试验钢中析出相特征及其强化作用。试验结果表明,22MnB5钢与Ti-V-Mo微合金钢淬火后的显微组织均为典型的板条马氏体,而两者的析出相除渗碳体外,Ti-V-Mo微合金试验钢中还析出了TiC以及少量的(V,Mo)C,经试验测量,抗拉强度比22MnB5钢提高90 MPa以上。600℃回火1 h后,Ti-V-Mo微合金试验钢中析出大量尺寸为20 nm以下的纳米级MC(M=Ti+V+Mo)型析出相,使得马氏体钢有效晶粒尺寸细化到约1.3μm。通过理论分析发现,其析出强化作用可达500 MPa以上,同时,由于(Ti,V,Mo)C析出相钉扎晶界使得晶粒细化而产生的细晶强化效果为70 MPa以上,在析出强化和细晶强化综合作用下,Ti-V-Mo微合金试验钢比22MnB5钢的强度提高600 MPa以上。因此,根据本研究的结果,Ti-V-Mo微合金试验钢在一定程度上改善了钢板材料在中温成形时出现的软化现象。Using warm forming instead of hot forming can avoid the problems of surface oxidation in the process of hot forming,but 22 MnB5 steel is commonly used in hot forming,and obvious softening occurs after high temperature tempering.By adding microalloyed elements such as Ti,V and Mo to the steel,fine precipitates and fine grains can be formed in the steel to improve the strength,so this problem can be solved.Therefore,by adding Ti,V and Mo microalloyed elements to 22 MnB5 steel,the characteristics and strengthening effect of precipitates in the experimental steel were studied by OM(optical microscope),FE-SEM(field emission scanning electron microscope),EBSD(electron backscattering diffraction),TEM(transmission electron microscope),XRD(X-ray diffraction analysis),EDS(energy dispersive spectrometer)and physicochemical phase analysis.The experimental results show that the microstructure of 22 MnB5 steel and Ti-V-Mo microalloyed steel after quenching is typical lath martensite.In addition to carburizing,TiC and a small amount of(V,Mo)C are also precipitated in Ti-V-Mo microalloyed experimental steel.The experimental measurement shows that the tensile strength is more than 90 MPa higher than that of 22 MnB5 steel.After tempering at 600℃for 1 h,a large number of nano MC(M=Ti+V+Mo)precipitates with a size of less than 20 nm precipitated in Ti-V-Mo microalloy experimental steel,which refined the effective grain size of martensitic steel to about 1.3μm.Through theoretical analysis,it is found that the precipitation strengthening effect can reach more than 500 MPa.At the same time,the fine grain strengthening effect caused by grain refinement due to the pinning of(Ti,V,Mo)C precipitates at the grain boundary is more than 70 MPa.Under the combined action of precipitation strengthening and fine grain strengthening,the strength of Ti-V-Mo microalloy experimental steel is more than 600 MPa higher than that of 22 MnB5 steel.Therefore,according to the results of this study,Ti-V-Mo microalloy experimental steel improves the soften

关 键 词：马氏体钢 Ti-V-Mo微合金化 强化作用 纳米级碳化物 析出相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]