Corrosion of tensile wires covered with PA11 layers in simulated annulus environments at low CO2 pressure

Abstract

AbstractHigh‐strength carbon steel wires covered with polymer layers were exposed to different test environments simulating the conditions in the annulus of flexible pipes at low CO2 pressure and flooded with seawater. The polymer layers mimicked the antiwear tapes which are placed in between the steel layers of the tensile armor of the pipes. Specimens without the polymer layer were exposed to the same test environments for comparison and allowed identifying how the presence of the polymer layer influenced the corrosion mechanism. In some of the experiments, oxygen was introduced into the gas mixture to simulate fresh seawater entering the annulus after a breach in the outer sheath. Surface analysis of the corroded specimens after removal of corrosion scales was carried out by scanning electron microscopy, optical profilometry, and confocal microscopy. The polymer layers were observed to have a considerable effect on the corrosion morphology.