A modified Remote Crevice Assembly (RCA) test was developed to permit crevice corrosion initiation and propagation evaluation of tubular products under dynamic flow conditions. Testing was conducted on alloy N06625 pipe specimens in flowing natural and chlorinated seawater environments. This was accomplished with electrically coupled pipe specimens appropriately masked with epoxy to create separate anode and cathode members. Crevices were formed on the pipe outside diameter by application of vinyl sleeves. Corrosion potentials and currents of electrically coupled and uncoupled assemblies were monitored and the effect of cathode to anode area ratio was investigated. Calculated crevice corrosion propagation rates are compared to actual depth of attack measurements on the specimens.

Propagation rates were higher in natural seawater than nominally 1 mg/L chlorinated seawater. Increased cathode area did not produce a significant change in propagation rates in natural seawater but did increase corrosion propagation in chlorinated seawater.

Subject
Cathodes, Piping, Corrosion currents, Chlorinated seawater, Natural seawater, Seawater, Crevices, Corrosion attacks, Corrosion propagation, Crevice corrosion, Alloys, Corrosion potential, Anodes
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1990
Association for Materials Protection and Performance (AMPP)
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