Constitutive description of high temperature flow behavior of Sanicro-28 super-austenitic stainless steel

The flow stress behavior of a super-austenitic stainless steel (Sanicro-28) was predicted through developing constitutive equations. These were established through utilizing the hot compression tests results acquired in the temperature range of 800-1100 °C under the strain rates of 0.001-0.1 s−1. The effects of the temperature and strain rate on hot deformation behavior were expressed in terms of an exponent-type Zener-Hollomon equation. The influence of strain was considered in the sine hyperbolic constitutive analysis by taking the related material constants into account as the functions of true strain. It was found that the deformation activation energy (Q) and the material constants in the model (i.e., α, β, n, and ln A) were polynomial functions of true strain. The Q-values were found to be in the range of 495-660 kJ/mol for different amounts of strain. The accuracy of the proposed constitutive equations was assessed using standard statistical parameters such as correlation coefficient and average absolute relative error. The results confirm that the developed constitutive equations may well predict the high temperature flow behavior of the examined super-austenitic stainless steel under the experimental deformation conditions.