Hot deformation behavior and processing maps of Cr₂₀Ni₈₀ electrothermal alloy

To solve the problem of forging cracks,the hot deformation behavior of Cr₂₀Ni₈₀ electrothermal alloy was investigated by compression tests on a Gleeble-1500 D thermal simulation machine in a temperature range of 900 to 1220℃ and a strain rate of 0.001 to 10 s^-1. The hot processing map of the alloy was established according to the dynamic materials model(DMM). It is found that the true stress-true strain curves have steady-state flow characteristics. The peak stress increases with decreasing deformation temperature or increasing strain rate. The flow behavior is described by a hyperbolic sine constitutive equation,and the activation energy of the alloy is about 371.29 kJ·mol^-1. Based on the processing map,the process of hot deformation in the temperature range at different strain rates can be attained,of which the optimum hot deformation temperature ranges in 1050-1200℃ and the strain rate is 0.03-0.08 s^-1,and the instability zones of flow behavior can also be recognized. The optimal hot-working technology is validated to be successful in production.