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

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ailing Wang ◽  
Yong Deng ◽  
Kaihong Li ◽  
Wenlei Li ◽  
Dongliang Yu ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Permeation ◽  
Pipeline Steel ◽  
Hydrogen Permeability ◽  
Permeation Flux ◽  
Stray Current ◽  
Content Type ◽  
Absorption Ratio ◽  
X80 Steel ◽  
Ac Interference

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.

Effect of AC interference on hydrogen evolution reaction of x80 steel

2020 ◽  
Vol 67 (2) ◽  
pp. 197-204
Author(s):  
JiaYu Zhou ◽  
Zili Li ◽  
JianGuo Liu ◽  
Xiao Xing ◽  
Gan Cui ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Electrode System ◽  
Oxygen Absorption ◽  
Content Type ◽  
Tafel Polarization ◽  
X80 Steel ◽  
Ac Interference

Purpose The purpose of this paper is to quantify the influence of alternating current (AC) interference on hydrogen evolution reaction of X80 steel. Design/methodology/approach The hydrogen evolution potential was obtained by cathodic potentiodynamic polarization curve. The instantaneous potential under AC interference was obtained by high-frequency acquisition with three-electrode system. Electrochemical impedance spectroscopy and Tafel polarization curves were used to study the influence mechanism of AC interference on instantaneous potential. Findings It was concluded that the hydrogen evolution reaction could occur on X80 steel under AC interference. There were critical AC current densities of about 100 to 200 A/m2, beyond which the cathode reaction of X80 steel changed from oxygen absorption to hydrogen evolution. Besides the pH value, the initial polarization potential EZ and impedance module of the steel/electrolyte interface under AC interference were also the factors that affected the critical AC densities in different solutions. Originality/value This research quantified the hydrogen evolution capacity of X80 steel under AC interference, which could be applied to clear the effect of AC interference on hydrogen evolution reaction.

Corrosion behavior of X80 steel under disbond coating interfered with AC

2019 ◽  
Vol 66 (6) ◽  
pp. 704-718
Author(s):  
Qingmiao Ding ◽  
Zili Li ◽  
Tao Shen ◽  
Gan Cui
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
The Self ◽  
Stray Current ◽  
Content Type ◽  
X80 Steel ◽  
Protection Potential

Purpose This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method. Design/methodology/approach The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference. Findings The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased. Originality/value This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

Corrosion Behavior of Pipeline Steel With Stray Current Interference at Coating Defects

2020 ◽  
Author(s):  
Ming Li ◽  
Xiaolin Wang ◽  
Maocheng Yan ◽  
Lei Shi ◽  
Jianan Wang ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Transmission Lines ◽  
Layer Structure ◽  
Pipeline Steel ◽  
Rapid Development ◽  
Local Environment ◽  
Stray Current ◽  
X80 Pipeline Steel ◽  
Coating Defect ◽  
Ac Interference

Abstract With rapid development of the economy, more and more power transmission, railway systems and oil/gas pipelines have been constructed in recent years. There have been many cases of pipelines crossing or paralleling to adjacent high-voltage transmission lines or railways. Corrosion caused by AC or DC interference is increasingly prominent and has received increasing attention for buried pipelines. In this work, a crevice cell was constructed to simulate the local environment on the surface of pipeline steel under disbonded coating in a soil environment. Corrosion behavior of X80 pipeline steel under stray current interference is investigated in the crevice cell. The results show that the AC interference shifts the local potential to the negative direction and markedly increases anodic dissolution of the steel. The attack of pipeline steel at the coating defect is the most serious, while corrosion attack slightly alleviates under the coating disbondment. Influence of stray current interference on corrosion behavior of pipeline steel under the coating defect was discussed from aspects of the commutation effect of AC interference, the irreversibility of anode reaction and effect of AC on the double layer structure at steel/solution interface.

Fractal characteristics of AC corrosion morphology of X80 pipeline steel in coastal soil solution

2019 ◽  
Vol 66 (6) ◽  
pp. 868-878
Author(s):  
Yu Fu ◽  
Jie Kou ◽  
Cuiwei Du
Keyword(s):  
Fractal Dimension ◽  
Soil Solution ◽  
Corrosion Behavior ◽  
Pipeline Steel ◽  
Three Dimensional ◽  
Uniform Corrosion ◽  
X80 Pipeline Steel ◽  
Corrosion Morphology ◽  
Content Type ◽  
X80 Steel

Purpose Pipelines are seriously corroded due to the close distance between pipelines and high voltage transmission lines. The purpose of this paper is to study the influence of alternating current (AC) on corrosion behavior of X80 pipeline steel in coastal soil solution. Design/methodology/approach The corrosion behavior of X80 steel under different AC densities in coastal soil solution was investigated by electrochemical measurements and image processing technology. Furthermore, a quantitative description model of AC corrosion through fractal dimension of corrosion image was established. Findings The results show that under low AC density the X80 steel is mainly uniform corrosion, and once AC density reaches 150 A/m2, the corrosion morphology gradually turns to pitting corrosion with irregular circle. For another aspect, the fractal dimension of corrosion images shows that the two/three-dimensional fractal dimension increase with the increase of AC density, presenting a linear and an exponential relationship respectively. In addition, the variation of the three-dimensional fractal dimension is the same as that of average corrosion rate. The threshold of the increasing trend of fractal dimension as well as corrosion type is 150 A/m2. Originality/value The investigation provides a quantitative method to describe AC corrosion morphology through fractal dimension. Furthermore, the method is of benefit to process corrosion images automatically.

scholarly journals Study on the Influence of AC Stray Current on X80 Steel under Stripped Coating by Electrochemical Method

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yanyu Cui ◽  
Tao Shen ◽  
Qingmiao Ding
Keyword(s):  
Current Density ◽  
Electrochemical Method ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Open Circuit ◽  
Stray Current ◽  
Ac Power ◽  
Initial Stage ◽  
X80 Steel ◽  
Ac Interference

The effect of AC stray current density on corrosion behavior of X80 steel with stripped coating defects was studied by electrochemical method. The experimental results showed that the open circuit potential of X80 steel was shifted negatively due to the existence of AC interference. The degree of negative shift increased with the increasing of AC stray current density. And the potential after the cut of AC interference was still more negative than before. That is, the corrosion interference continued after cutting the AC power. In the initial stage of the experiment, the corrosion current density with 30A/m2 AC stray current interference was about 1.4 times of that without AC interference, while the corrosion current density with 50A/m2 AC stray current interference was about two times of that without AC interference.

scholarly journals Effect of a DC Stray Current on the Corrosion of X80 Pipeline Steel and the Cathodic Disbondment Behavior of the Protective 3PE Coating in 3.5% NaCl Solution

Coatings ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 29 ◽  
Author(s):  
Xinhua Wang ◽  
Zuquan Wang ◽  
Yingchun Chen ◽  
Xuting Song ◽  
Yong Yang
Keyword(s):  
Direct Current ◽  
Current Density ◽  
Pipeline Steel ◽  
Three Dimensional ◽  
Steel Corrosion ◽  
Cathode Region ◽  
Nacl Solution ◽  
Stray Current ◽  
X80 Pipeline Steel ◽  
X80 Steel

The influence of a direct current (DC) stray current on the corrosion and cathodic disbondment of X80 steel coated with a polyethylene (3PE) coating in 3.5% NaCl solution was studied by immersion experiments, electrochemical tests, three-dimensional microscopy, and a surface analysis. The results showed that the potential of the X80 steel sample shifts under the direct current. After 100A/m2 DC interference was applied, the potential of the sample in the anode region positively shifted from –0.68 to –0.43 V. At the same time, the sample in the cathode region negatively shifted to –1.45 V. Under the DC anode action, the X80 steel corrosion exhibited no passivation and followed Faraday’s law of electrolysis, in which the corrosion rate is proportional to the current density. Three-dimensional (3D) digital microscopy showed that, as the DC current increased, the depth of the corrosion pit also increased (gradually), indicating a higher corrosion degree. The sample in the cathode region only underwent a hydrogen evolution reaction, which caused cathodic disbondment of the coating. The stray current had a critical current density for the coating disbonding: the coating delamination area reached its maximum and then remained unchanged.

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

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanbao Guo ◽  
Zhenyuan Liu ◽  
Hui Huang ◽  
Deguo Wang ◽  
Renyang He
Keyword(s):  
Corrosion Rate ◽  
Stress Corrosion ◽  
Cathodic Protection ◽  
Oil And Gas ◽  
Strain Curve ◽  
Stray Current ◽  
Cathodic Potential ◽  
Content Type ◽  
Opposite Behavior ◽  
X80 Steel

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.

scholarly journals Analysis of Hydrogen Permeation Through Pipeline Steel in Near-Neutral pH SCC Environments

2000 ◽  
Author(s):  
Yufeng Cheng ◽  
Lin Yang ◽  
Fraser King
Keyword(s):  
Organic Material ◽  
Hydrogen Permeation ◽  
Pipeline Steel ◽  
Open Circuit ◽  
Permeation Flux ◽  
Concentration Boundary ◽  
Sulfate Reducing ◽  
Neutral Ph ◽  
Disulphonic Acid ◽  
Reducing Bacteria

The Devanathan-cell technique has been used to determine the permeation flux of hydrogen through X-65 steel at the open-circuit potential in solutions associated with near-neutral pH stress corrosion cracking. The effects of organic material and microbial activity were also simulated by suitable additions to the solution. A model based on a constant-concentration boundary condition was found to fit the experimental data better than one based on a constant flux condition. The addition of 9,10-anthroquinone-2,6-disulphonic acid to the solution to simulate the effect of organic material lowered the hydrogen permeation flux. Sulfide additions to simulate the action of sulfate-reducing bacteria initially increased the rate of hydrogen permeation, but subsequently resulted in a decrease in permeation current. The hydrogen permeation rate measured on the original oxide-covered surface is lower and more variable than that on polished surfaces. Corrosion rate measurements were also made, from which the fraction of atomic hydrogen diffusing through the specimens was estimated. The results are discussed in terms of the mechanism of hydrogen evolution and absorption.

Characterization of the fracture behaviour of X42 microalloyed pipeline steel

2015 ◽  
Vol 6 (5) ◽  
pp. 567-577
Author(s):  
Halil Ibrahim Ünal ◽  
Hakan Atapek ◽  
Baran Gürkan Beleli ◽  
Seyda Polat ◽  
Serap Gümüs ◽  
...  
Keyword(s):  
Fracture Behaviour ◽  
Pipeline Steel ◽  
Sheet Material ◽  
Sheet Steel ◽  
Grain Morphology ◽  
Tensile Fracture ◽  
Pipe Material ◽  
Content Type ◽  
Fracture Surfaces ◽  
Impact Tests

Purpose – The purpose of this paper is to investigate the fracture of grade X42 microalloyed steel used as pipe material after tensile test at room temperature and impact tests at 0, −20 and −40°C, respectively. Design/methodology/approach – In the first stage of the study, X42 steels in the form of sheet and pipe materials were selected and etched samples were characterized using light microscope. In the second stage, mechanical properties of steels were obtained by microhardness measurements, static tensile and impact tests and all the broken surfaces were examined by scanning electron microscope to determine the fracture type as a function of both microstructure and loading. Findings – The examinations revealed that: first, the sheet material had a typical ferritic-pearlitic matrix, second, the transverse section of the sheet steel exhibited a matrix consisting of polygonal ferrite-aligned pearlite colonies and the longitudinal one had elongated ferrite phase and pearlite colonies in the direction of rolling, third, ferrite and pearlite distribution was different from the sheet material due to multiaxial deformation in the pipe material, fourth, tensile fracture surfaces of the steels had typical dimple fracture induced by microvoid coalescence, fifth, impact fracture surfaces of the steels changed as a function of the test temperature and cleavage fracture mode of ferritic-pearlitic matrix became more dominant as the temperature decreased, and sixth, grain morphology had an effect on the fracture behavior of the steels. Originality/value – The paper explains the fracture behaviour of X42 microalloyed pipeline steel and its fractographical analysis.

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