Prediction of creep crack growth behaviour in 316H stainless steel for a range of specimen geometries

• The CCG behaviour in different geometries has been predicted by FE simulations.
• A stress dependent creep ductility model is employed in damage calculations.
• Higher CCG trends in the low C* region observed in tests are numerically predicted.
• Lower CCG trends are found in M(T) geometry indicating low constraint level.
• Similar CCG rates are predicted for AR and PC materials in the high/low C* regions.

The specimen geometry and constraint effects on the creep crack growth behaviour of Type 316H stainless steel at 550 °C have been examined over a wide range of load levels using finite element simulations. Creep crack growth predictions are performed on a range of specimen geometries by employing stress dependent creep ductility and strain rate trends in creep damage calculations. The predicted creep crack growth rates are characterised using the C* fracture mechanics parameter and validated through comparison with the existing experimental data. Comparisons have been made between the predicted short term and long term creep crack growth behaviour in different specimens and the results are discussed in terms of the specimen constraint effects on the crack growth behaviour of the material. Two material states including as-received and pre-compressed conditions have been considered and their predicted creep crack growth results are compared in each of the specimen geometries examined.