New numerical method for the fit of Garofalo equation and its application for predicting hot workability of a (V–N) microalloyed steel

Abstract

A new method, Rieiro, Carsí, Ruano (RCR), for solving the Garofalo equation is developed. This method is based on an integrated algorithm that allows determination of the equation parameters for any given material and does not need initial values. The RCR method is used to analyse the Garofalo equation best fit applied to torsion data at various temperatures and strain rates from a (V–N) microalloyed steel. The predictive capability of the RCR method on experimental results is ∼6% in stress and the magnitude of the predicted errors is of the same order as the interpolation errors. On the other hand, the n value is slightly lower and the Q value slightly higher than those expected for a slip creep mechanism controlled by lattice diffusion. However, the obtained values agree with those found in the literature for microalloyed steels. These differences can be attributed to microstructure changes during deformation.

Keywords:

• MICROALLOYED STEEL
• NUMERICAL METHODS
• GAROFALO EQUATION
• TORSION TESTS