Distribution Characteristics and Thermal Stability of Primary Carbide in Cast Ce-H13 Steel

Abstract

The primary carbide precipitated during the solidification process will act as the crack source to reduce the performance of H13 steel. It is necessary to obtain the nature of the primary carbide in H13 steel to reduce its detriment. Therefore, the distribution characteristics and thermal stability of the primary carbide in cast Ce-H13 steel were analyzed in this paper. There is a huge difference in the shape of the primary carbide between the 2D observation and the 3D observation. The shape of the primary carbide is a dendritic structure, and the branch is rich-V carbide and the trunk is rich-Ti-V carbide. The primary carbide size in the 3D observation increases gradually from the margin of the Ce-H13 ingot to the center. The rapid growth of the branch leads to an increase in size, and the decrease in the cooling rate is the main reason for the increase in size. When the heating temperature is 1150°C, the rich-V carbide starts to dissolve and dissolved completely at 1250°C. However, the rich-Ti-V carbide just starts to dissolve when the heating temperature is 1250°C. The number density and size of primary carbide decrease gradually with the increase of the heating temperature. Elemental Ce can effectively decrease the size of the primary carbide, but not for the number density. The calculated results are in keeping with the experimental observations. High-temperature heating can effectively reduce the primary carbide size, but cannot eliminate it.