Validation of Deformation in Crystal Plasticity When Modelling 316H Stainless Steel for Use in Pressure Vessels

Abstract

Abstract The safety critical nature of high temperature/pressure power plants means that understanding the mechanical behaviour of materials used remains a priority. Current design and assessment codes are conservative due to the macroscale estimates used in their construction so to improve these standards the mesoscale should be taken into account. A commonly used method to simulate this lengthscale is crystal plasticity finite element (CPFE) which allows for efficient simulation of mesoscale phenomena. This paper presents and validates key components of a crystal plasticity model used to predict the deformation seen within 316-H stainless steel at elevated temperature. This validation is done by capturing intra-granular (type-III) stress profiles obtained using cross correlation of high resolution electron backscatter diffraction patterns (HR-EBSD) at different stages during loading to 3% plastic strain. Two exercises were performed to investigate the model’s ability to predict the correct active slip systems and slip transmission across boundaries. The model was found to be able to correctly predict the most active slip system seen experimentally in 90% of grains. In addition to this the stress gradients observed near boundaries showed larger magnitudes at higher grain boundary misorientations in both the model and the experiment. The stress distributions explored matched between model and experiment for some boundaries but not all types. This may be due to the over simplification of the simulation geometry.