Hu, J.; Lin, G.; Deng, P.; Li, Z.; Tian, Y. Galvanic Corrosion of E690 Offshore Platform Steel in a Simulated Marine Thermocline. Metals2024, 14, 287.
Hu, J.; Lin, G.; Deng, P.; Li, Z.; Tian, Y. Galvanic Corrosion of E690 Offshore Platform Steel in a Simulated Marine Thermocline. Metals 2024, 14, 287.
Hu, J.; Lin, G.; Deng, P.; Li, Z.; Tian, Y. Galvanic Corrosion of E690 Offshore Platform Steel in a Simulated Marine Thermocline. Metals2024, 14, 287.
Hu, J.; Lin, G.; Deng, P.; Li, Z.; Tian, Y. Galvanic Corrosion of E690 Offshore Platform Steel in a Simulated Marine Thermocline. Metals 2024, 14, 287.
Abstract
Marked changes in temperature, pH, dissolved oxygen (DO) content, and nutrient content typically occur in marine thermoclines, which are key factors that affect the corrosion of metals. Offshore platforms have required marine metals to be exposed to deep-sea environments and have thus increased their penetration into the marine thermocline. This study investigates the galvanic corrosion of E690 steel in a marine thermocline using a simulated marine thermocline (SMT). Specifically, the corrosion of E690 steel was analyzed using the wire beam electrode (WBE) technique, linear polarization (LP), corrosion morphology, and weight loss measurement. Results indicated that the SMT had a stable multilayer structure, and the variations of temperature, DO, pH and nutrient concentration in the SMT were similar to those in the natural marine thermocline. Galvanic corrosion occurred after the intrusion of E690 steel into the marine thermocline. The driver of galvanic corrosion was the of E690 steel at various depths of the marine thermocline. The Ecorr of E690 steel was influenced by the temperature, pH and DO of seawater, and the order was DO >> T > pH. The continuous reduction of Ecorr with depth contributed to the large-scale galvanic corrosion, and the oscillation variation of Ecorr with depth was the reason for small-scale galvanic corrosion. The primary anodic regions of galvanic corrosion were located in the area with the fastest temperature variation in the thermocline. The proportion of galvanic corrosion in the average corrosion rate could increase up to approximately 80% in the stable anodic region. There were many deep corrosion pits in the long-term and stable anodic region of galvanic corrosion.
Copyright:
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