The search for reliable inputs in modelling hot working operations: a model describing the flow behavior of metals at high temperature applied to CW602N brass

Finite element modeling allows the optimization of metalworking processes and enhances the quality of the product, in terms of properties and microstructure, as attested by the success of recent finite element modeling codes in simulating the microstructural evolution during hot deformation. Hot working of metals involves several concurring phenomena; in particular, dynamic and static recrystallizations depend on the energy stored in the grains during and after deformation, i.e. on the strain accumulated in the material. As a result, the correct estimation of the accumulated strain plays a crucial role in modelling the final microstructure. A new constitutive model based on the combination of the Garofalo and Hensel-Spittel equations has been thus recently proposed to describe the plastic flow behavior of an aluminum alloys. The new equation was used in the present paper to model the equivalent stress vs. equivalent strain curved obtained by testing in torsion between 550 and 700 degrees C a CW602N (Cu-36% Zn-2% Pb-As) brass. Interpolation of the experimental data using the constitutive model resulted in an excellent description of the flow curves, thus demonstrating that the combined use of the new equation and of torsion testing can be safely adopted in a computer code to simulate forging or extrusion.