Hardness-based flow stress and fracture models for numerical simulation of hard machining AISI 52100 bearing steel

The phenomenological models of flow stress and fracture typically used in the computer simulation of machining processes do not adequately represent the constitutive behavior in hard machining, where the workpiece is heat treated to 52–64 HRC prior to machining. This paper proposes the hardness-based flow stress and fracture models for numerical simulation of hard machining. These models are based on the well known Johnson–Cook flow stress model and the Brozzo’s facture criteria. The paper includes the development of the hardness-based flow stress model for the AISI 52100 bearing steel, the development of the hardness-hydrostatic stress based fracture criteria, the implementation of these models in a non-isothermal viscoplastic numerical model of machining, and the simulation of machining for various hardness values and machining parameters. Predicted results are validated by comparing them with experimental results from literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the hardness values change.