Compact tension 316H austenitic steel specimens, extracted from an as-received ex-service pressure vessel header, have been pre-compressed to different load levels in order to introduce a residual stress field. Finite element (FE) analysis has been performed to predict the load level required to obtain a high magnitude tensile stress field over a significant distance ahead of the notch while preventing a large plastic zone in the specimen. The predicted residual stress profiles along the crack path are compared with those measured using neutron diffraction (ND). Comparisons have also been provided between the ND results of this work with recent work carried out on 316H and 347 stainless steels under different loading levels. The creep relaxation behaviour of the steel has been studied numerically. A proposed method to estimate the steady state creep crack tip parameter, C*, has been examined using the obtained displacement rates for the case of combined loading. Creep relaxation data for combined stresses are compared with the earlier studies.

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