The R5 procedure uses a ductility exhaustion approach to calculate the creep damage observed in the heat affected zone (HAZ) of thick section 316H austenitic stainless steel weldments. The present work considers the influence of thermo-mechanical history on the creep ductility and creep damage accumulation under a condition of multiaxial stress state. A systematically designed pre-treatment procedure was used to introduce a range of microstructures, representative of those observed in the HAZ of these weldments. Double notched bar creep specimens were manufactured and used to investigate creep behaviour of 316H stainless steel at a temperature of 550°C. The rate of creep strain accumulation is shown to be a function of the thermo-mechanical pre-treatment. The accumulation of creep damage is correlated with the microstructure and stress state. Finally, the results are discussed with respect to the sensitivity of the currently used ductility exhaustion model to the key material inputs, in terms of the uniaxial creep ductility, multiaxial stress state and stress relaxation rate.
|Translated title of the contribution||Effect of multiaxial stress state and microstructure on creep properties of austenitic stainless steel|
|Title of host publication||International Conference on Engineering Structural Integrity Assessment, Manchester|
|Publication status||Published - 2011|