Use of REM-based modifying agents for improving the structure and properties of cast tungsten-molybdenum high-speed steels

Special features of the structure and properties of cast high-speed steels R6M5K5 and R6M5 modified by REM-based additives, i.e., ferrocerium in a design amount of 0.1, 0.3, 0.6, and 1.2% and silicomishmetal and alumoyttrium in a design amount of 0.1, 0.3, and 0.6% are studied. Results of metallographic, x-ray diffraction, fracture surface, and microscopic x-ray spectral analyses of the steels after casting, annealing, hardening, and tempering are discussed. It is shown that the modifying changes the chemical composition, morphology, and distribution of the carbide component in the steels. Relation between the structural parameters and the characteristics of mechanical properties is determined.