Effects of plastic pre-straining level on the creep deformation, crack initiation and growth behaviour of 316H stainless steel

• The rupture time and creep ductility found to decrease by increasing the percentage of pre-straining.
• The average and minimum creep strain rates found relatively insensitive to pre-compression.
• The creep ductility of the 4%, 8% and 12% PC materials followed the estimated trend for the AR material.
• Similar CCG behaviour was observed in the 4% and 8% PC specimens.
• 12% PC data provided a conservative estimate of the long term CCG behaviour in the AR material.

The effects of the material pre-straining level, in the form of plastic pre-compression at room temperature, on the tensile, creep deformation, creep crack initiation and growth behaviour of 316H stainless steel have been examined at 550 °C. Experiments have been performed on the 4%, 8% and 12% pre-compressed specimens and the results are compared with existing data on the pre-compressed material to investigate the change in mechanical response, creep failure, creep crack initiation and growth behaviour of 316H over a range of plastic pre-straining levels. Comparisons are also made to short term and long term test data on the as-received material. It has been found that creep ductility and rupture times decreased with an increase in pre-strain levels considered. The test results obtained from different material states are discussed in terms of the influence of material pre-straining level on the microstructural deformation, mechanical response, creep deformation and crack growth behaviour of the material.