NOWAK Jarosław

Spoluautoři SVYETLICHNYY Dmytro S., PIDVYSOTS’KYY Valeriy

In the paper a flow stress model based on internal variables is shortly presented. The model is multiplicative; it considers three factors. The first one is so called “master” curve, which is a modified model base on the Taylor’s dislocation theory. It strongly depends on strain and very weakly on temperature and strain rate. The second factor introduces the deformation conditions: temperature and strain rate. Its main feature is the consideration of varying deformation conditions. Changes of flow stress, as shown by experimental tests, occur not simultaneously with the change of deformation conditions, but it requires specific strain. The third factor considers influence of recrystallization. An essential feature of the recrystallization model based on the Kolmogorov-Johnson-Mehl-Avrami (KJMA) theory is the accounting of the effect of recovery on the kinetics of static recrystallization. Model parameters were identified on the data obtained in the experimental tests carried out on the physical simulator GLEEBLE-3800. One-staged deformation tests were fulfilled at constant and varying conditions. Relaxation tests are succeeded as well. Three-staged deformation process was chosen for verification. Two variants with different initial temperature are performed. Results of comparison of theoretical calculations by the proposed model with experimental data are presented in the paper. The results confirmed the high accuracy and the efficiency of the model.