METHOD OF PRODUCTION OF CARBON-FREE CASTING HEAT- RESISTANT NICKEL-BASED ALLOYS Russian patent published in 2004 - IPC

FIELD: metallurgy; production of nickel-based heat-resistant alloys; melting carbon-free heat- resistant alloys for casting turbine blades of gas-turbine engines and other parts with mono-crystal structure. SUBSTANCE: proposed method includes melting charge materials in vacuum; two-stage decarburization refining at introduction of oxidant in inert gas atmosphere at pressure of 20-150 mm Hg followed by introduction of rare-earth metals. Chromium and active alloying elements in vacuum; after introduction of active alloying elements into melt, calcium is introduced in the amount of 0.02- 0.20% of mass of at pressure of inert gas of 20-130 mm Hg, after which vacuum is formed and lanthanum is introduced in the amount of 0.01- 0.30% of mass of melt in vacuum of 10^-2-5•10^-4 mm Hg. Proposed method makes it possible to reduce content of sulfur in melt below 0.001%. EFFECT: improved heat-resistant properties of alloy at retained low content of carbon. 3 cl, 1 tbl, 1 ex