In this work, the effectiveness of cathodic protection (CP) at corrosion defects on an UNS T30102† steel pipeline was investigated both experimentally and numerically. A finite element model was developed to simulate distribution of local potential inside the defect. Results demonstrated that there is a non-uniform potential distribution at corrosion defects. The CP is shielded, at least partially, at the defect, especially at its bottom. This effect is enhanced with increasing depth and decreasing width of the defect. Empirical equations are derived to enable calculation of CP effectiveness at corrosion defects, providing industry recommendations for accurate assessment of further corrosion allowance and remaining life of pipelines in the field.

Subject
Steel surfaces, Surface defects, Modeling, Geometry, Cathodic potential, Microprobes, Pipelines, Steel electrodes, Negative potentials, Defects, Steel, Corrosion potential, Electrode potential
Keywords:
Pipelines, Corrosion defects, Cathodic protection, Numerical assessment
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2014
Association for Materials Protection and Performance (AMPP)
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