Using an Inverse Cutting Simulation-Based Method to Determine the Johnson-Cook Material Constants of Heat-Treated Steel

Abstract

The Johnson-Cook approach is a common model used for machining simulations which represents the material behavior by taking 5 material constants into consideration. Johnson-Cook constants are available for a large number of materials, in the majority for such with a widespread application or which are in the focus of research activities. Material models for e.g. heat-treated steels are hardly to find. The material constants can be determined by means of material tests with the objective to get information about the thermo-mechanical material characteristics. To consider the complex cutting conditions with their large temperature and time gradients in the contact zone, expensive technical equipment is a perquisite. An alternative to this practice is the determination of material constants by means of inverse simulation based methods. Therefore experimental designs with varied material constants are being prepared within predefined value ranges by means of DoE approaches. In addition cutting tests are performed to get relevant comparison criteria e.g. forces or chip shape characteristics with the objective to fit and validate the simulation results regarding to realistic material constants. This article deals with the inverse procedure to determine the Johnson-Cook material constants of the heat treatable steel SAE 4142 with the hardness 42 HRC. It describes simulation and experimental techniques regarding to orthogonal cutting in groove turning and the valuation of using the gained material constants in material models for cutting simulations.