Structure and phase composition of high-speed steels

Abstract

This work is devoted to the study of the structure and phase composition of high-speed steels R6M5, R9 and R18. High service properties of high-speed steel tools are achieved by heat treatment. Therefore, the sample blanks for the study were cut from cutting tools from R6M5, R9 and R18steels, which were subjected to
the usual standard heat treatment for these steels. Installed that the structure of high-speed steels R6M5, R9 and R18 in the initial state, i.e. after standard heat treatment, consists of martensite and special carbides. The carbide particles are evenly distributed in the matrix and are close to the correct spherical shape. Thus in the structure of steels R6M5 and R9 are carbides of type М₆С, MC, and in the structure of steel R18 only carbides of the type М6С. EBSD analysis showed that M₆C carbides are most optimally combined with the Fe₃W₃C cubic phase, and the MS type carbide corresponds to the VC phase. Electron microscopic analysis showed that in addition to M₆C and MС carbides, high-speed steel contains small amounts of «cementite» type М₃С carbides.