Corrosion Fatigue Performance of Super 13 Cr, Duplex 2205 and 2507 for Riser Applications

Corrosion fatigue performance of Super 13Cr, 2205, 2507 for use as riser materials in environments containing high partial pressures of carbon dioxide (50 - 100 bar) and limited quantity of hydrogen sulfide (0 - 0.12 bar) will be presented.  The procedures developed for controlling oxygen and Fe²⁺ contamination as well as methods to evaluate the concentration of H₂S in the autoclave will also be discussed.  S-N curve data as well as fatigue crack growth rate data for these materials will be presented along with procedures to minimize misalignment will be presented.  The crack growth rates and DK_th for these materials in the pressure environments will be discussed along with procedures to obtain DK_th, when they are below 5ksiÖin and low crack growth rates in the range of 1e-8 in/cycle will be presented.