Effect of severe cold work on the microstructure and SSC resistance of superduplex stainless steel downhole tubulars

Cold worked superduplex stainless steels have been used as downhole tubulars for many years. However, problems during manufacture may result in areas of the tubulars exhibiting additional localised cold work. The effects of such damage on the SSC and SCC performance of tubulars has not been documented. To address these concerns, a programme of work was conducted to characterise the microstructure developed in cold-worked superduplex stainless steel downhole tubulars as a result of damage during manufacture. Samples of material exhibiting different degrees of microstructual refinement as a result of the additional cold work were subjected to SSC testing. Test results and recommendations are presented.