Investigating the mechanical properties of case carburised steels

The objective of this study is to measure the material properties of the case section in case carburised steels. This data is to be used for the validation of a material model that can be applied at the design stage for heat treated components. Material properties are acquired through tensile testing of heat treated steel specimens. Tensile test specimens were uniformly heat treated prior to testing. A standard tensile test was conducted on these samples. Following this a grinding operation was used to remove equal amounts of the case from each side, and the same tensile test repeated. Specimens were tested with varying amounts of the case removed, including a specimen where the entire hardened layer was ground away. Data was acquired through the Zwick Z100 test machine, extensometer and an Imetrum Video Strain Gauge (VSG) system to monitor displacements and strain within the specimens. The data was then compared with a theoretical material model and used to validate a Finite Element (FE) model that incorporates a user defined Functionally Graded Material (FGM) parameter to apply the material properties as a function of depth within the case