新型压力容器用钢25CrMo3NiTiVNbZr的析出相特征和强化机制  

Characteristics and strengthening mechanism of precipitated phase of a new type of pressure vessel steel 25CrMo3NiTiVNbZr

作　　者：李若浩 王中成 梁恩溥 何肖飞[1] 徐乐[1] LI Ruo-hao;WANG Zhong-cheng;LIANG En-pu;HE Xiao-fei;XU Le(Research Institute of Special Steels,Central Iron and Steel Research Institute Co Ltd,Beijing 100081,China;Inner Mongolia North Heavy Industries Group,Baotou 014010,China)

机构地区：[1]钢铁研究总院有限公司特殊钢研究院,北京100081 [2]内蒙古北方重工业集团有限公司,内蒙古包头014010

出　　处：《材料热处理学报》2024年第2期129-138,共10页Transactions of Materials and Heat Treatment

摘　　要：为了进一步提高25Cr3Mo3NiNbZr钢的室温力学性能,对其进行成分优化,设计制备了25CrMo3NiTiVNbZr钢。利用场发射扫描电镜(SEM)、透射电镜(TEM)、电子背散射衍射(EBSD)技术以及拉伸试验机等研究了两种试验钢经1050℃淬火及640℃回火2 h后的室温力学性能、析出相特征和强化机理。结果表明:25Cr3Mo3NiNbZr钢主要析出相为纺锤状富Mo的M_(2)C相,其平均直径为18 nm,25CrMo3NiTiVNbZr钢中析出了更加细小的M_(2)C和MC碳化物,其平均直径为7.93 nm。25CrMo3NiTiVNbZr钢的室温抗拉强度达到1412 MPa,屈服强度达到1279 MPa,相比25Cr3Mo3NiNbZr钢分别提高了283和336 MPa。通过理论计算,两种试验钢室温下的强化机制均以析出强化、细晶强化和位错强化为主,其中25CrMo3NiTiVNbZr钢的位错强化增量和析出强化增量较25Cr3Mo3NiNbZr钢明显增加,分别增加了174和205 MPa。In order to further improve the room temperature mechanical properties of 25Cr3Mo3NiNbZr steel,composition optimization was carried out for it,and 25CrMo3NiTiVNbZr steel was designed and prepared.The room temperature mechanical properties,precipitated phase characteristics and strengthening mechanisms of the two experimental steels quenched at 1050 ℃ and tempered at 640 ℃ for 2 h were studied by means of field emission scanning electron microscopy(SEM),transmission electron microscopy(TEM),electron backscatter diffraction(EBSD) technique and tensile testing machines.The results show that the main precipitated phase in the 25Cr3Mo3NiNbZr steel is spindle-shaped Mo-rich M_(2)C phase,with an average diameter of 18 nm.Finer M_(2)C and MC carbides are precipitated in the 25CrMo3NiTiVNbZr steel,with an average diameter of 7.93 nm.The room temperature tensile strength of the 25CrMo3NiTiVNbZr steel reaches 1412 MPa,and the yield strength reaches 1279 MPa,which is 283 and 336 MPa higher than the 25Cr3Mo3NiNbZr steel,respectively.Through theoretical calculations,the strengthening mechanisms of the both experimental steels at room temperature are mainly precipitation strengthening,grain refinement strengthening and dislocation strengthening.Among them,the dislocation strengthening increment and precipitation strengthening increment of the 25CrMo3NiTiVNbZr steel are significantly increased compared to the 25Cr3Mo3NiNbZr steel,with an increase of 174 and 205 MPa,respectively.

关 键 词：25CrMo3NiTiVNbZr钢 成分优化 强化机制 纳米析出相 

分 类 号：TG142.3[一般工业技术—材料科学与工程]