Towards a physical FE modelling of a dry cutting operation: influence of dynamic recrystallization when machining AISI 1045

Whether analytical or numerical, models of a machining operation require important input data such as friction laws or material constitutive models to reach accurate results. Recent experimental studies provided a better fundamental understanding of the cutting process especially regarding the thermo-mechanical conditions associated to the chip formation. However, in most of the numerical works, the deformation behaviour of materials is still represented by a simple empirical equation. This contribution therefore aims at improving the physical meaning of a FE cutting model by the use of an advanced constitutive equation. After an emphasis on the microstructural evolutions occurring in cutting, a dynamic compression test campaign is conducted to assess the material behaviour at high strains. A "metallurgy based" constitutive model, taking into account a dynamic recrystallization process, is identified. It clearly leads to a better description of the thermo-mechanical behaviour than the commonly used Johnson & Cook's model, also identified based on these experiments. Finally, the latter are implemented in a FE code (Abaqus/Explicit (c)) via a VUMAT (c) subroutine. An ALE 2D orthogonal cutting model is then involved to assess their performance as well as the effect of the dynamic recrystallization in machining. Numerical results are compared to experimental data in orthogonal cutting conditions as well as identifications of Johnson & Cook's model conducted in the literature. (C) 2013 The Authors. Published by Elsevier B.V.