FIELD: manufacture of rotors for layer-size gas turbines. SUBSTANCE: iron-nickel superalloy-comprises wt %: carbon, not higher than 0.002; silicon not higher than 0.10; manganese, not higher than 0.20; sulfur, not higher than 0.002; phosphorus, not higher than 0.015; chromium, 15-18; nickel, 40-43; aluminum, 0.1-0.3; cobalt, not higher than 0.30; titanium, 1.5-1.8; copper, not higher than 0.30; niobium 12.8- 3.2; boron, 0.02-0.3; and/or hafnium, 0.05-1.5; and iron, the balance. Method of preparing highly heat resistant material from said alloy comprises diffusion annealing of initial semiproduct in furnace at temperatures from 900 to 1000 and subsequently thermally strengthening at temperatures from 600 to 65O C in second stage. EFFECT: higher heat resistance of the alloy, improved forgeability and greater fatigue resistance thereof. 8 cl, 1 ex, 2 tbl
