Study on hydrogen permeation behavior of X80 steel under AC stray current interference

Abstract

Purpose Alternating current (AC) corrosion is a type of corrosion that occurs in buried pipelines under AC stray current interference, which can increase the hydrogen embrittlement sensitivity of pipelines. However, rare research works have been conducted on the hydrogen permeability characteristics of pipeline steel under AC stray current interference. The purpose of this paper is to study hydrogen permeation behavior of X80 steel under AC stray current interference. Design/methodology/approach In this paper, the hydrogen permeation behavior of X80 steel under AC interference is studied by AC hydrogen charging experiment in a dual electrolytic cell. The relationship between hydrogen evolution rate and hydrogen permeation flux is studied using the gas collection method. The difference between AC hydrogen permeability and direct current (DC) hydrogen permeability is also discussed. Findings The anodic dissolution caused by AC corrosion promotes the chemical desorption reaction of the adsorbed hydrogen atoms on the surface, reducing the hydrogen atom absorption ratio by 70%. When the AC is smaller than 150░ A/m2, the hydrogen permeation process is controlled by the hydrogen atom generation rate, and the hydrogen permeation flux increases with the increase in hydrogen atom generation rate. When the AC exceeds 400░ A/m2, the hydrogen permeation process is controlled by the absorption ratio. The hydrogen permeation flux decreases with the decrease in the absorption ratio. Under AC interference, there is a maximum hydrogen permeation flux that linearly correlates to the H+ concentration in the solutions. Originality/value The high-strength steel is very sensitive to hydrogen embrittlement, and X80 steel has been widely used in oil and gas pipelines. To date, no research has been conducted on the hydrogen permeation behavior of pipeline steel under AC interference, and the hydrogen permeability characteristics of pipeline steel under AC interference are not clear. The research results of this paper are of great significance for ensuring the intrinsic safety of high-strength pipelines under AC stray current interference.

Research on the stress corrosion and cathodic protection of API X80 steel under AC stray current interference

“…It is evident that the main reason for this type of corrosion is the existence of AC. The result is consistent with the report of Wang et al (2021) that under the combined effects of hydrogen and stress, SCC behavior occurs in metals.…”

“…From Figure 10, we can see that the corrosion rate was changed with the CP potential. Figure 10 also confirms the findings of Wang et al that with the decreasing electrode potential, the corrosion degree of the sample first decreases and then increases, and the SCC sensitivity exhibits a certain rule (Wang et al , 2021).…”

“…Wang et al (2021) found that the mechanism of SCC is hydrogen-induced cracking at −1,275 mV (vs Cu/CuSO4 reference electrode, CSE). The sulfate-reducing bacteria exacerbates the cathodic hydrogen evolution at this potential.…”

“…However, pipelines often intersect and parallel with high-voltage transmission circuits and high-speed rail trains. Alternating current (AC) interference would aggravate the corrosion of metal materials (Correa, 2013; Guo et al , 2016; Guo et al , 2017; Wang et al , 2021).…”

Corrosion of X80 steel in the co-existence of sulfate reducing bacteria and permeating hydrogen

“…There are intricate interactions between microorganisms, and the biofilm and corrosion products generated by metabolic processes can promote or hinder the corrosion process (Li et al , 2013; Lv et al , 2022; Liu et al , 2022). In addition, under the condition of hydrogen-mixed transportation, hydrogen atoms will inevitably penetrate into the pipes, which easily causes corrosion fatigue, stress corrosion, hydrogen embrittlement and other phenomena (Wang et al , 2021). Meiring (Lv et al , 2021) studied the effect of SRB on hydrogen permeation and stress corrosion cracking behavior of high-strength steel in the seawater environment and found that SRB would raise the risk of stress corrosion cracking of high-strength steel.…”