THE EFFECT OF CATHODIC PROTECTION POTENTIAL ON CORROSION FATIGUE CRACK GROWTH RATE OF AN OFFSHORE STRUCTURAL STEEL |
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| Authors: | J Yu R Brook I Cole D Morabito G Demofonti |
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| Affiliation: | School of Engineering, Sheffield Hallam University, S1 1WB, UK;Department of Engineering Materials, University of Sheffield, S1 4DU, UK;CSIRO, Melbourne, Australia;Centro Sviluppo Materiali, Rome, Italy |
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| Abstract: | Abstract— Duplicate tests have been performed to determine the effect of cathodic protection potential on corrosion fatigue crack growth rate of a modern offshore structural steel, produced by thermo-mechanically controlled processes. The experiments were carried out using compact tension specimens exposed to artificial seawater at 10°C and subjected to constant amplitude loading at 0.35 Hz. Reproducible results showed that the merits of cathodic protection potentials are strongly dependent on stress intensity ratio R and stress intensity range Δ K . It appears that a specific value of cathodic potential may not give comprehensive protection against corrosion fatigue within the spectrum of variable amplitude loading experienced in service. Fractography showed the initiation of secondary cracks on the fracture surface to be associated with the dissolution of calcium sulphide inclusions, regardless of imposed cathodic potential. |
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| Keywords: | Offshore structural steel Cathodic protection Corrosion fatigue Stress ratio effect |
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