Flow behaviour and constitutive modeling for hot deformation of austenitic stainless steel

The flow behavior of 316H austenitic stainless steel is investigated using hot compression tests. The modified Johnson-Cook and Zerilli-Armstrong models are developed, and modified Arrhenius-type model is established using an approach by dividing low and high stress region for determining key material constant and an uncomplicated approach for compensating strain in which the activation energy is determined from peak stress and only other material constants are considered as strain-dependent constants. The performance of all developed constitutive models is comparatively analyzed. It is indicated that the significant sensitivity of flow stress to temperature and strain rate is exhibited, and at 900 and 950 degrees C, strain rate sensitivity is closely related to temperature and strain rate, which can be explained by low stacking fault energy for 316H austenitic stainless steel. The modified Arrhenius type model has a noticeably higher accuracy in predicting flow behaviour than other two developed models in spite of a good performance of all developed models according to visual examination and statistical analyses.