Long-term creep data prediction for type 316H stainless steel

Impressive data sets have been produced for 316H stainless steel (18Cr–12Ni–Mo with up to 0.08C) by the National Institute for Materials Science (NIMS), Japan, to reveal the dependencies on stress and temperature of the high-temperature creep and creep fracture behavior of nine batches of tube, six of bar and two of plate. Using these long-term property values, the stresses to produce failure in 100,000 h at various plant exposure temperatures have been determined using the Manson–Haferd parameter. However, by incorporating the 0.2% proof stresses and ultimate tensile strengths of each batch of material at the creep temperatures, new relationships allow accurate prediction of the allowable tensile creep stresses using data from tests lasting only up to 5000 h. Moreover, all of these results can be interpreted straightforwardly in terms of the dislocation processes controlling creep strain accumulation and the cavitation damage causing creep failure.