Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Autor: V. I. Eremenko, N. M. Semenova, D. D. Vaulin, O. Kh. Fatkullin, S. N. Petrova, O. N. Vlasova, N. N. Korneeva
Rok vydání: 1991
Předmět:
Zdroj: Metal Science and Heat Treatment. 33:924-931
ISSN: 1573-8973
0026-0673
Popis: To provide a high level of mechanical properties in wrought blanks of cast EP741NP and EP962 alloys it is necessary to form controlled structures. A “necklace”-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (γ+γ′)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment. To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.
Databáze: OpenAIRE
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