Chemical composition and structural identification of primary carbides in as-cast H13 steel

作     者：Ming-tao Mao Han-jie Guo Fei Wang Xiao-lin Sun 

作者机构：School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing 100083 China Central Iron & Steel Research Institute Beijing 100081 China 

出 版 物：《International Journal of Minerals,Metallurgy and Materials》 (矿物冶金与材料学报（英文版）)

年 卷 期：2019年第26卷第7期

页      面：839-848页

核心收录：

学科分类：0806[工学-冶金工程] 08[工学] 

基　　金：financially supported by the National Natural Science Foundation of China (Nos. U1560203 and 51274031) the Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials at School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, China 

主　　题：primary carbide phase identification H13 steel precipitation thermodynamic 

摘      要：The aim of this study was to characterize the primary carbides formed in as-cast H13 steel. The composition, morphology, type, and size of primary carbides in as-cast H13 steel were investigated by optical microscope (OM), field emission scanning electron microscopy (FE-SEM), electron back-scattered diffraction (EBSD), and X-ray diffraction (XRD) analysis. The number of primary carbides was investigated by ASPEX automated inclusion analysis system. The results indicated that primary carbides in as-cast H13 steel are mainly composed of Cr, Mo, V, and Ti, and there exist four kinds of primary carbides in the interdendritic zones of H13 steel, which are stripy Mo–Cr-rich M2C, eutectic Mo–Cr-rich M2C, V-rich MC, and V-rich MC with Ti and N. Thermodynamic calculation indicated that M2C precipitates in liquid phase at solid fractions larger than 0.99, while MC precipitates in liquid phase at solid fractions larger than 0.96. Statistical results indicated that the number of M2C is much greater than the number of other kinds of primary carbides. Most primary carbides are blocky, with lengths of no more than 10 μm and a length/width ratio of no more than 3. The large primary carbides in as-cast H13 steel are mainly M2C.