Investigation of static relations between heat treatment conditions, grain sizes and mechanical properties of ep718-id alloy rings

Statistical relationships of a grain size and mechanical properties depending on conditions of tempering EP718-ID heat-resistant alloy rings have been determined. Temperatures of hardening heat (1080-1100 °С) and grain sizes (~85-95 mc) were substantiated, ensuring the optimal complex of mechanical properties of the rings: σ0,2 = 710 MPa; σв = 1200 MPa; δ = 29%; ψ = 40% (at room temperature); time to failure τf = 110-115 h (at 600 °С, 785 MPa). Regression models were obtained, which allow us to estimate average values of the rings’ mechanical properties depending on temperature of hardening heat (after double aging).