Dissolution of Large‐Sized Primary Carbides in 6Cr13 Continuous Casting Slabs during High‐Temperature Homogenization

Abstract

The morphology of carbides, the distribution of alloying elements, and the dissolution of primary carbides in 6Cr13 continuous casting slabs during the high‐temperature homogenization process are studied herein. The results show that severe segregation of alloying elements exists at the center of the cast slabs, accompanied by large, interconnected primary carbides in the form of a network. Large‐sized reticulated primary carbides are difficult to completely dissolve and eliminate during homogenization treatments. Large‐sized primary carbides will dissolve along the contours and the joints between the carbides when the temperature of high‐temperature homogenization does not exceed 1250 °C and the time does not exceed 1 h. The carbides that had broken off will precipitate again along the original contour in the form of large‐sized brain‐like carbides beyond this temperature and time. In situ observation of the high‐temperature homogenization process reveals that when the slab is heated to 1200 °C, the local liquid phase starts to be generated around the carbide. Cr atoms diffuse into the matrix through the liquid–matrix interface; it will accelerate the high‐temperature homogenization process and improve the segregation of alloying elements around carbides.