30NiCrMoV12高铁车轴钢连续冷却相变组织  

Continuous cooling phase transformation microstructure of 30NiCrMoV12 steel for high-speed railway axle

作　　者：黄军波 何毅 霍洁 陈楚 HUANG Jun-bo;HE Yi;HUO Jie;CHEN Chu(Natinal-local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die&Mould,Tianjin University of Technology and Education,Tianjin 300222,China;Research Institute of Shandong Iron&Steel Group Company Limited,Ji’nan 250101,China;Tianjin Heavy Equipment Engineering Research Co Ltd,CFHI,Tianjin 300457,China)

机构地区：[1]汽车模具智能制造技术国家地方联合工程实验室,天津职业技术师范大学,天津300222 [2]山东钢铁集团有限公司研究院,山东济南250101 [3]中国一重天津重型装备工程研究有限公司,天津300457

出　　处：《材料热处理学报》2021年第1期132-139,共8页Transactions of Materials and Heat Treatment

摘　　要：为了确定30NiCrMoV12高铁车轴钢在连续冷却过程中的相变类型,研究了大直径高铁车轴钢淬火时截面上不同冷速下的相变组织。结果表明:在0.01~2℃/s的冷速范围内,实验钢的相变组织主要为贝氏体和马氏体。在0.01~0.5℃/s的冷速区间形成的贝氏体形貌复杂多样。随冷速升高,实验钢的组织依次为粒状贝氏体(GB)、上贝氏体(UB),以及板条束较粗的下贝氏体(LB1)和较细的下贝氏体(LB2)。透射电镜下组织观察表明,在冷速更快、转变温度更低条件下形成的LB2,其贝氏体板条更细小,板条中碳化物更密集细小,位错密度更高,显微硬度亦比LB1高出约30 HV0.05。30NiCrMoV12钢具有良好的淬透性,全尺寸大直径车轴在水淬状态下从表层到心部的微观组织依次是马氏体、下贝氏体LB2、下贝氏体LB2+LB1,基本能够保证截面组织和性能的均匀性,满足高铁车轴的均质化要求。For determining the phase transformation type of 30 NiCrMoV12 high-speed railway axle steel during continuous cooling, the phase transformation microstructure of high-speed railway axle steel with large diameter under different cooling rates was studied. The results show that the transformation microstructure of the experimental steel is mainly bainite and martensite in the cooling rates range of 0.01-2 ℃/s. The morphology of bainite formed in the cooling rate range of 0.01-0.5 ℃/s is complex and diverse. With the increase of cooling rate, the microstructure of the experimental steel is granular bainite(GB), upper bainite(UB), and coarse-lath lower bainite(LB1) and finer-lath lower bainite(LB2). The results of TEM microstructural observation show that the bainitic lath of the LB2 which formed at faster cooling rates and lower transition temperature is smaller, the carbide in the lath is denser and smaller, the dislocation density is higher, and the microhardness is about 30 HV0.05 higher than that of the LB1. The 30 NiCrMoV12 steel has good hardenability, and the microstructure of the full-size large-diameter high-speed railway axle steel from the surface layer to the center after water quenching is martensite, the lower bainite LB2 and the lower bainite LB2 and LB1, which can basically guarantee the uniformity of the section microstructure and properties and meet the requirements of homogenization of the high-speed railway axle.

关 键 词：高铁车轴 相变 显微组织 

分 类 号：TG142.3[一般工业技术—材料科学与工程]