Hardness-based flow stress for numerical simulation of hard machining AISI H13 tool steel

The phenomenological models for material flow stress and fracture typically used in the finite element simulations of hard machining processes do not adequately represent the constitutive behavior of the workpiece that is usually heat treated to hardness levels ranging from 50 to 62 HRC. Thus, new flow stress models which include also the hardness effect should be developed and used accordingly in computer simulation of hard machining. This paper describes the development of a hardness-based flow stress and fracture models for machining AISI H13 tool steel, which can be applied for a wide range of work material hardness. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the influence of work material hardness on the chip formation process. Predicted results are validated by comparing them with experimental results from literature. They are found to predict well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the hardness values change.