A FE based machining simulation methodology accounting for cast iron microstructure

• A FE based machining simulation methodology accounting for cast iron microstructure.
• Assessment of cast iron machinability at orthogonal cutting.
• A parametric study is carried out based on micrographs of cast iron with varying nodularity.
• FE-simulated and experimental cutting forces and chip formations compare fairly well.

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 (CGI) material in a related paper. It turns out that the FE-simulated and experimentally observed cutting force and chip formation compare fairly well.