Corrosion behaviors of X70 steel under direct current interference
Anti-Corrosion Methods and Materials
ISSN: 0003-5599
Article publication date: 15 January 2019
Issue publication date: 25 April 2019
Abstract
Purpose
The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution.
Design/methodology/approach
The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy.
Findings
The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution.
Originality/value
All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.
Keywords
Citation
Wang, J., Li, Z., Cui, G., Liu, J., Kong, C., Wang, L., Gao, G. and Guo, J. (2019), "Corrosion behaviors of X70 steel under direct current interference", Anti-Corrosion Methods and Materials, Vol. 66 No. 3, pp. 307-316. https://doi.org/10.1108/ACMM-08-2018-1992
Publisher
:Emerald Publishing Limited
Copyright © 2019, Emerald Publishing Limited