The influence of two variants of initial soaking at 1120 °C / 2 h and 1180 °C / 2 h and parameters of hot plastic working on the deformability of an IN 718 type superalloy have been presented. The hot deformation characteristics of alloy were investigated by hot torsion tests. The tests were executed at constant strain rates of 0.1 s-1 and 1.0 s-1, and testing temperature in the range of 900 °C to 1150 °C. Plastic properties of the alloy were characterized by worked out flow curves and the temperature relationships of maximum flow stress (σpp) and strain limit (εf). The relationship between the maximum flow stress and the Zener-Hollomon parameter (Z) was described by σpp = A · Zn power function. Activation energy for hot working (Q) was assessed for the alloy after two variants of initial soaking, i.e. 1120 °C / 2 h and 1180 °C / 2 h and amounted - respectively - 478 kJ/mol and 628 kJ/mol.Keywords: IN 718 superalloy, hot deformation, plastic properties, Zener-Holomon parameter, activation energy for hot working
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