Prediction of flow stress of alloyed steel in hot forming by applying different mathematical models and design of experiment

Abstract

In the past decades, a great number of mathematical models have been developed to describe the rheological behaviour of metals and alloys in hot forming conditions. Many different approaches have been used for determining the constitutive equation, i. e. the complex and non-linear relationship between flow stress and various forming process factors. In this paper some relatively simple mathematical models for predicting the flow stress of alloyed steel during the hot forming process were investigated. In order to model the constitutive response of the material, the flow stress was determined as a function of main factors, such as strain, strain rate and temperature. After analyzing the results of calculation, the constitutive low was selected that represents the best-fit flow curve model. The absolute percentage errors and correlation coefficient indicate that the proposed flow curve could predict the flow stress in real forming conditions with good correlation and generalization. Also, this flow curve can easily be utilized in engineering calculations and numerical simulations