Investigation of Statistical Relationships between Heat Treatment Modes, Grain Sizes, and Mechanical Properties of EP718-ID Alloy Rings

Statistical dependences of grain size and mechanical properties on the conditions of hardening of rings of industrial production from the heat-resistant alloy EP718-ID have been established. The heating temperatures for quenching (1080–1100°C) and grain sizes (~85–95 μm) providing the optimal set of mechanical properties of the rings are substantiated: σ 0.2 = 710 MPa, σ t = 1200 MPa, δ = 29%, ψ = 40% (at room temperature); time to failure τ f = 110–115 h (at 600°C, 785 MPa). Regression models have been obtained that make it possible to estimate the average statistical values of mechanical properties of rings made of the EP718-ID alloy depending on the heating temperature for quenching (after double aging).