A FE based machining simulation methodology accounting for cast iron microstructure

Artikel i vetenskaplig tidskrift, 2014

In the present paper the effect of graphite nodularity in the microstructure of cast iron is assessed with respect to its machinability at orthogonal cutting. A micro-structure based model of the cast iron material has been developed based on analyses of micro-graph images. The image analysis combines pearlitic grains with graphite nodules to produce the micro-structures. Continuous deformation behavior of pearlite and graphite phases is described using the Johnson-Cook (JC) viscoplasticty model including temperature dependence. Of particular concern is the modeling of the chip formation, induced by the micro-structure morphology and the mechanical behavior of the work piece material in the vicinity of the insert. This is described by the element deletion methodology along with the Johnson-Cook failure criterion to realize the fracture kinematics. A parametric study is carried out by varying the nodularity of the graphite. To validate the model, the finite element results are compared to machining test results carried out on a Compacted Graphite Iron (CGl) material in a related paper It turns out that the FE-simulated and experimentally observed cutting force and chip formation compare fairly well.