Chemically-bonded enamel-coated steel pipelines for corrosion protection and flow efficiency

"This study is to explore and develop chemically-bonded enamel coating (200-300 um) on steel pipes, when subjected to soil and thermal environments, in order to improve the corrosion protection and safety of hazardous liquid and natural gas pipelines while reducing pressure loss. Out of five types of enamels and their various mixtures, Tomatec slurry and GP2118 powder were selected for steel pipeline applications. They were applied at approximately 810 °C to the inside surface of steel pipes in wet and electrostatic processes, respectively. The thickness and surface roughness of the enamel coating were measured using a gauge and an optical microscope, respectively. The microstructure and porosity of the coating, and coating-steel bond strength were characterized using scanning electron microscopy and PosiTest, respectively. The corrosion resistance of enamel-coated pipelines, with and without cathodic protection (CP), is evaluated using salt spray and electrochemical tests. The stress distribution of enamel-coated pipes and their susceptibility to stress corrosion cracking (SCC) were studied with finite element analyses and slow strain rate tests, respectively. The surface roughness of the two coatings were ~ 1 μm and quite desirable in oil and gas transmission. Small Fe protrusions grew into each coating to form anchor points with a bond strength of 17 MPa between the enamel and its steel substrate. The residual thermal stress remained at the coating-steel interface is 2.5 MPa and thus negligible. Both enamel coatings increased the corrosion resistance of steel pipes in NaCl solution by three orders of magnitude. CP neither caused debonding at the coating-steel interface nor accelerated degradation process of the coating. The more negative the applied CP potential, the more susceptible to SCC the enamel-coated stee"--Abstract, page iii.

Name thesis:degree_name

Ph. D. in Civil Engineering

Grantor

Missouri University of Science and Technology

Author dc:creator

• Fan, Liang

• Corrosion protection
• Enamel coating
• Flow efficiency
• Steel pipeline
• Civil Engineering
• Materials Science and Engineering

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2775

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3780