Hot deformation behavior and processing maps of Cr20Ni80 electrothermal alloy

Abstract

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.

Keywords

• electrothermal alloys
• chromium nickel alloys
• hot compression
• hot deformation
• processing maps