OPTIMIZATION OF THE HEAT TREATMENT CYCLES OF WROUGHT SEMIFINISHED PRODUCTS OF MEDIUM-ALLOY HIGH-TEMPERATURE STRENGTH NICKEL ALLOYS

1. Use of the proposed low-temperature treatment in place of the standard one provides an increase in and stabilization of the mechanical properties and low-cycle fatigue resistance (by 10%) of KhN73MBTYu and KhN77TYuR alloy forgings as the result of formation of a uniform fine-grained recrystallized structure, more intense precipitation of carbides at the grain boundaries, and formation of uniform γ′-phase particles. 2. With use of the standard heat treatment of KhN73MBTYu alloy correction of the second solution treatment temperature is recommended taking into consideration the temperature of full solution of γ′-phase of the specific heat. With this a stable level of mechanical properties of the alloy is obtained.