Effects of pre-corrosion and cathodic protection in artificial seawater on S-N fatigue behavior of X80 steel

The effects of pre-corrosion and applied potentials in artificial seawater on the S-N fatigue behavior of X80 steel were examined. The X80 specimens were pre-corroded in a FeCl3 solution for varying immersion times ranging from 0 to 96 h and subsequently S-N fatigued in air. It was found that the resistance to S-N fatigue decreased abruptly with 1 h immersion, while it became saturated with a further increase in immersion time. The trend observed in this study was relatively well explained by the stress concentration effect from the presence of corrosion damage on the surface. The in-situ S-N fatigue tests were also conducted on X80 steel in artificial seawater under applied potentials of -600, -850 and -1,050 mV (SCE). The fractographic and micrographic analyses were conducted on the fatigue specimens to identify the optimum cathodic protection conditions.