Laboratory coating evaluation and its relationship with the selection to protect pipeline against external corrosion
- INTEVEP, S.A., Caracas (Venezuela). Material Technology Dept.
There are several pipeline external coatings classified into different types, among them are extruded and tape polyethylene, fusion bonded epoxy (FBE), coal tar enamel, coal tar epoxy, polyurethane, wax, cementitious epoxy and multilayer systems. These coatings are assumed to protect the pipeline for a certain period of time. In order to select the most appropriate coating, several accelerated laboratory tests need to be carried out to obtain their properties and correlate them with the performance in the field. Cathodic disbonding tests at different temperatures and voltages, adhesion at different temperatures, impact resistance, loss of adhesion against time under water immersion conditions, differential scanning calorimetry analysis and water uptake are the most important tests to carry out in this study. The results indicate that coatings perform differently in each test. For this reason the selection must be done according to the soil characteristics, considering the results obtained in laboratory. This paper will provide a guideline to select a coating for a specific environment and the results that should be expected in the field. For example, the multilayer system presented the best performance like low cathodic disbonding, excellent adhesion, high impact resistance, excellent behavior under hot water immersion and high temperature resistance. This system can be used in all types of soil with high life time expectancy in protecting the pipeline. On the other hand, the polyurethane coating presented high impact resistance but very low adhesion and high cathodic disbonding that limits its use in corrosive soil.
- OSTI ID:
- 352637
- Report Number(s):
- CONF-980316-; TRN: IM9928%%231
- Resource Relation:
- Conference: Corrosion `98, San Diego, CA (United States), 22-27 Mar 1998; Other Information: PBD: 1998; Related Information: Is Part Of Corrosion `98: 53. annual conference and exposition, proceedings; PB: [6600] p.
- Country of Publication:
- United States
- Language:
- English
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