MODELLING OF MATERIAL FLOW STRESS IN CHIP FORMATION PROCESS FROM ORTHOGONAL MILLING AND SPLIT HOPKINSON BAR TESTS

ABSTRACT Estimation of flow stress of the work material is central to both analytical and numerical modelling of the machining process. Results from split Hopkinson's pressure bar (SHPB) testing were used as a starting point for the estimation of flow stress. Subsequently material flow stress valid in the context of chip formation was computed from analytical model based on results from orthogonal milling tests. The milling operation involving cyclic variation of thickness of cut was carried out for a range of cutting speeds, generating information about flow stress over a wide range of strain, strain rate, and temperatures. Two work materials differing in phase content, namely pure ferritic (REMKO) and pure austenitic (AISI 316L) were the reference materials evaluated in this study.