Determination of flow stress and the critical strain for the onset of dynamic recrystallization using a hyperbolic tangent function

• Flow stress curves at high temperatures are modeled with a new equation.
• The new model is based on hyperbolic tangent with an additional parameter.
• An equation is derived to predict the onset of dynamic recrystallization.

A new model has been developed to estimate the flow stress under hot deformation conditions up to the peak of the stress–strain curves. This model is derived from the general form of hyperbolic function by introducing an additional parameter to bring the results to a more acceptable level. Stress–strain curves and the critical strain of a ‘304 austenitic stainless steel’ are determined with an average percentage error of 1.24. The model is also used to obtain an equation which has the ability of predicting the critical strain for the onset of dynamic recrystallization.