HIGH SPEED STEEL TURNINGS REMELTING IN PLASMA-INDUCTION FURNACE BY ARGON-NITROGEN PLASMA

A high-efficiency technology for high speed steel turnings remelting in plasma-induction furnace with inert gas blowing through bottom electrode-anode is developed. Possibilities for nitrogen gas alloying, using argon-nitrogen plasma, is the main subject of this work. The study includes: investigation on electric regime of induction furnace and plasma torch working parameters during the melting process; determination of alloying elements oxidation; investigation on influence of nitrogen blowing through bottom electrode - anode on temperature and chemical composition homogeneity as well as nitrogen content in metal. The advantages of this technology are: using cheap scrap; reduced ferroalloys consumption; alloying steel with nitrogen instead of expensive nitrided ferroalloys; improved quality of final products due to better homogeneity of chemical composition and structure.