MODIFYING CAST TUNGSTEN-MOLYBDENUM HIGH-SPEED STEELS WITH NIOBIUM, ZIRCONIUM, AND TITANIUM

摘要

The influence of modifying additives of niobium, zirconium, and titanium on the structure and properties of cast tungsten-molybdenum high-speed steels R6M5 and R6M5K5 is studied. Results of metallographic and x-ray diffraction analyses and of studies of fracture surfaces of the steels after casting, annealing, hardening, and tempering are discussed. The relationship between structural parameters, the degree of contamination of the metal by nonmetallic inclusions, and mechanical properties is established. It is shown that modifying with the mentioned elements in optimum amounts primarily promotes an increase in the impact toughness and wear resistance of the metal.