Hot deformation behaviors and flow stress model of GCr15 bearing steel

Abstract

The hot deformation behaviors of GCr15 bearing steel were investigated by isothermal compression tests, performed on a Gleeble-3800 thermal-mechanical simulator at temperatures between 950 ℃ and 1 150 ℃ and strain rates between 0.1 and 10 s −1 . The peak stress and peak strain as functions of processing parameters were obtained. The dependence of peak stress on strain rate and temperature obeys a hyperbolic sine equation with a Zener-Hollomon parameter. By regression analysis, in the temperature range of 950−1 150 ℃ and strain rate range of 0.1−10 s −1 , the mean activation energy and the stress exponent were determined to be 351 kJ/mol and 4.728, respectively. Meanwhile, models of flow stress and dynamic recrystallization (DRX) grain size were also established. The model predictions show good agreement with experimental results.

Modeling of flow stress for magnesium alloy during hot deformation

“…Based on experimental data and literature [30][31], it can be found that the critical strain ε c and ε 0.5 are function of initial grain size d 0 , deformation temperature T and strain rateε, and both of them can be described by equations which have the form similar to Eq. (7).…”

FLOW BEHAVIOUR AND MICROSTRUCTURAL EVOLUTION OF TITANIUM Ti-10V-2Fe-3Al ALLOY DURING HOT COMPRESSION TEST

“…The hyperbolic-sine law is applicable for a wide range of stresses. It is now well accepted that the influence of strain rate and temperature on flow stress during hot deformation could be satisfactorily expressed with the equation proposed by Sellars and Tegart which takes hyperbolic form [11], as is shown in equation [3]:…”

“…By combining equation [3] and equation [4], we can relate the strain rate, temperature and the flow stress to Zener-Holloman parameter (Z):…”

“…Flow behaviour during hot deformation processing is often considered to be complicated due to the occurrence of both hardening and softening during processing. The characteristics of flow curves are generally a direct consequence of microstructural changes during processing involving work hardening, dynamic recrystallization and dynamic recovery [3].…”

Dynamic Recrystallization of 18Ni(1700MPa) Maraging Steel During Hot Deformation

“…The understanding of metals and alloys behavior under hot deformation condition has a great importance to designers of metal forming processes because it can affect the required energy as well as the microstructure changes of deformed metal through work hardening, dynamic recovery (DRV) and DRX [1][2][3][4]. Constitutive equation, which relates to the stress, strain, strain rate and deformation temperature, is a powerful tool to describe material behavior during hot working.…”