Modeling the constitutive relationship of Cr20Ni25Mo4Cu superaustenitic stainless steel during elevated temperature

Isothermal compression tests at temperatures of 1273–1473 K and strain rates ranging from 0.01 to 10 s−1 were preformed on Cr20Ni25Mo4Cu superaustenitic stainless steel to reveal the hot deformation characteristics. In order to give a precise prediction of flow behavior, the obtained experimental data was employed to derive the constitutive relationship incorporating the effect of strain. It is found that the effect of temperature and strain rate on flow stress is significant and their relationship can be represented by the Zener–Hollomon parameter including Arrheuins term. The material constant in the model, such as α, n, Q and ln A functioned by the strain is identified using sixth order polynomial. The flow stresses calculated by the developed model are reasonable agreement with the experimental ones, which indicates that the constitutive relationship can effectively describe the high temperature flow behavior of Cr20Ni25Mo4Cu superaustenitic stainless steel and can be used to numerically analyze the hot deformation process of the present material.

► Compression tests for Cr20Ni25Mo4Cu alloy were conducted in a wide range of temperature and strain rate.
► The relations among stress, strain rate and temperature could be represented by Z-parameter including Arrheuins term.
► A constitutive model incorporating the effect of strain was developed.
► The material constants functioned by the strain were identified using sixth order polynomial.
► The prediction results by the proposed model were reliable and the correlation coefficient was 0.988.