Super duplex stainless steel is susceptible to Hydrogen Induced Stress Cracking (HISC) under the
influence of a Cathodic Protection (CP) system. A study has been carried out investigating the influence
of CP potential on mechanical degradation of UNS S32750 Super Duplex umbilical tube using a Slow
Strain Rate Testing (SSRT) technique. The testing, at strain rate of 1x10-6 s-1, was performed on
specimens polarized in the range of -1050 mV to -400 mV at ambient temperature in ASTM artificial
seawater conditioned with and without hydrogen pre-charging. The impact of HISC was evaluated
through an assessment of the ratio of the elongation at fracture in the seawater to that in air.The
influence of CP potential, hydrogen content, and microstructure of the tube were examined. The
ductility and fracture mechanism of the samples were studied by SEM.
Keywords: Super Duplex Stainless Steel tube, Cathodic Protection Potential, HISC, Slow Strain Rate
Testing