Corrosion behavior of X65 pipeline steel in coastal areas

Abstract

Purpose

To study the corrosion behavior of pipeline steel in coastal areas, a tidal seawater macro-cell corrosion device was built using a cycle soaking tank and a macro-cell corrosion facility to simulate the corrosion behavior of pipeline steel in a simulated coastal environment (dry and wet alternations during seawater-soil corrosion macro-cell processes).

Design/methodology/approach

The corrosion behaviors were studied via the weight loss method, electrochemical methods and morphological observations on corrosion.

Findings

The results show that during the initial stage of tidal seawater/soil macro-cell corrosion process of the X65 steel, the working electrode on the seawater side is the anode of the macro-battery. As corrosion progresses, the anode and the cathode of the macro-battery become inverted. As the area ratio and the dry – wet ratio increase, the time of anode and cathode inversion shortens. Galvanic current density decreases as the dry – wet ratio increases and increases as the area ratio increases. The corrosion process of macro-cell is affected by the reversal of anode and cathode. After the reversal of anode and cathode, the corrosion rate is mainly controlled by dry – wet alternating corrosion.

Originality/value

The corrosion behavior of a pipeline steel in a coastal environment was studied using a tidal seawater macro-cell corrosion device. The synergism effect between the tidal seawater and seawater-soil macro-cell on corrosion behavior was clarified.

Citation

Sun, B., Liao, W., Li, Z., Liu, Z. and Du, C. (2019), "Corrosion behavior of X65 pipeline steel in coastal areas", Anti-Corrosion Methods and Materials, Vol. 66 No. 3, pp. 286-293. https://doi.org/10.1108/ACMM-06-2018-1953