METHOD OF PRODUCTION OF CARBON-FREE FOUNDRY HEAT RESISTING NICKEL-BASED ALLOYS Russian patent published in 2015 - IPC C22C1/02 C22C19/03 

FIELD: metallurgy.

SUBSTANCE: method of production of carbon-free foundry heat resisting nickel-based alloys is offered. The method includes the melting in vacuum of charge materials, decarbonising refinement in two stages. At the first stage the oxidiser is added in volume exceeding the volume necessary for oxidation of carbon to its dioxide 2.0-8.5 times in the atmosphere of inert gas at the pressure 20-150 hg mm, deacidification is performed and gas is removed. At the second stage the refinement is performed by adding of rare-earth metals the quantity of which 2.0-20.0 times exceeds the amount of carbon which remained in the molten metal after the first stage of refinement. Then before adding of active alloying elements chrome is added to molten metal. The oxidiser is added at least in two steps and after adding of each portion of oxidiser is held during the time τ, then deacidification is performed. The deoxidant is nickel-based ligatures containing alkaline-earth metals.

EFFECT: improvement of quality of the obtained work pieces without decrease of steadiness of crucibles.

4 cl, 1 tbl, 2 ex