Research on the stress corrosion and cathodic protection of API X80 steel under AC stray current interference
Anti-Corrosion Methods and Materials
ISSN: 0003-5599
Article publication date: 7 August 2021
Issue publication date: 19 August 2021
Abstract
Purpose
The corrosion of buried steel pipelines is becoming more serious because of stress corrosion, stray current corrosion and other reasons. This paper aims to study the various alternating current (AC) interference densities on the stress corrosion cracking behaviors of X80 steel samples under cathodic protection (CP) in the simulated soil electrolyte environment by using an electrochemical method.
Design/methodology/approach
The change of corrosion rate and surface morphology of the X80 steel samples at various AC current densities from 0 to 150 A/m2 or CP potential between −750 and −1,200 mV in the soil-simulating environment was revealed by the electrochemical methods and slow strain rate testing methods.
Findings
The results revealed that with the increase of interference density, the corrosion potential of the X80 steel samples shifted to the negative side, and the corrosion pitting was observed on the surface of the sample, this may cause a danger of energy leak. Moreover, the corrosion rate was found to follow a corresponding change with the stress–strain curve. Besides, with the introduction of the CP system, the corrosion rate of the X80 steel working electrode decreased at a low cathodic potential, while showed an opposite behavior at high cathodic potential. In this study, the correlation between AC stray current, cathodic potential and stress was established, which is beneficial to the protection of oil and gas pipeline.
Originality/value
Investigation results are of benefit to provide a new CP strategy under the interference of AC stray current corrosion and stress corrosion to reduce the corrosion rate of buried pipelines and improve the safety of pipeline transportation.
Keywords
Acknowledgements
This work is sponsored by the National Key Research and Development Program of China (No. 2018YFC0809004) and the Science Foundation of China University of Petroleum, Beijing (No. 2462020XKJS01).
Citation
Guo, Y., Liu, Z., Huang, H., Wang, D. and He, R. (2021), "Research on the stress corrosion and cathodic protection of API X80 steel under AC stray current interference", Anti-Corrosion Methods and Materials, Vol. 68 No. 4, pp. 346-353. https://doi.org/10.1108/ACMM-03-2021-2463
Publisher
:Emerald Publishing Limited
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