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Article
Publication date: 29 March 2021

Ailing Wang, Yong Deng, Kaihong Li, Wenlei Li, Dongliang Yu, Gan Cui, JianGuo Liu and Zili Li

Alternating current (AC) corrosion is a type of corrosion that occurs in buried pipelines under AC stray current interference, which can increase the hydrogen…

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.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 7 August 2021

Yanbao Guo, Zhenyuan Liu, Hui Huang, Deguo Wang and Renyang He

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…

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.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 13 August 2020

Mayur Pratap Singh, Dinesh Kumar Shukla, Rajneesh Kumar and Kanwer Singh Arora

The key purpose of conducting this review is to identify the issues that affect the structural integrity of pipeline structures. Heat affected zone (HAZ) has been…

Abstract

Purpose

The key purpose of conducting this review is to identify the issues that affect the structural integrity of pipeline structures. Heat affected zone (HAZ) has been identified as the weak zone in pipeline welds which is prone to have immature failures

Design/methodology/approach

In the present work, literature review is conducted on key issues related to the structural integrity of pipeline steel welds. Mechanical and microstructural transformations that take place during welding have been systematically reviewed in the present review paper.

Findings

Key findings of the present review underline the role of brittle microstructure phases, and hard secondary particles present in the matrix are responsible for intergranular and intragranular cracks.

Research limitations/implications

The research limitations of the present review are new material characterization techniques that are not available in developing countries.

Practical implications

The practical limitations are new test methodologies and associated cost.

Social implications

The fracture of pipelines significantly affects the surrounding ecology. The continuous spillage of oil pollutes the land and water of the surroundings.

Originality/value

The present review contains recent and past studies conducted on welded pipeline steel structures. The systematic analysis of studies conducted so far highlights various bottlenecks of the welding methods.

Details

International Journal of Structural Integrity, vol. 12 no. 3
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 7 June 2021

Shixiong Wu, Zhiming Gao, Da-Hai Xia, Meijun Wu, Yingjie Liu and Wenbin Hu

This paper aims to study the effect of temperature on the process and kinetic parameters of the hydrogen evolution reaction of X80 under cathodic protection (CP) in 3.5…

Abstract

Purpose

This paper aims to study the effect of temperature on the process and kinetic parameters of the hydrogen evolution reaction of X80 under cathodic protection (CP) in 3.5% NaCl solution.

Design/methodology/approach

Potentiodynamic polarization combined with the hydrogen permeation test is used to analyze the hydrogen evolution reaction (HER) process and the rate-determining step for which is diagnosed through the electrochemical impedance spectrum method. Then, the influence of temperature on kinetic parameters of HER can be known from the results obtained by using the Iver-Pickering-Zamenzadeh model for data analysis.

Findings

The results show that the HER proceeds through Volmer–Tafel route with the Volmer reaction acting as the rate-controlling step; Increasing temperature gives a higher activity of the HER on X80, it also accelerates the hydrogen desorption and diffusion of hydrogen into the metal.

Originality/value

There exist few studies on the topic of how temperature affects the HER process. It is imperative to conduct a relevant study to give some instruction in cathodic protection system design and this paper fulfills this need.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 8 November 2011

Shao Huai Qi, Zhang Qi Bin, Han Wen Li, Xie Bei Bei, Xu Zhong Ping and Huang Gui Bai

The purpose of this paper is to report the investigation of a low temperature application process for three‐layer polyethylene coating (3LPE) at 185‐195°C to meet the…

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Abstract

Purpose

The purpose of this paper is to report the investigation of a low temperature application process for three‐layer polyethylene coating (3LPE) at 185‐195°C to meet the requirement of the coating temperature for X80 longitudinally welded pipe.

Design/methodology/approach

Plant coating and laboratory tests were performed to determine the properties of 3LPE coating coated at 185‐195°C.

Findings

The properties of the 3LPE coating, which was applied by using a suitable low temperature cured epoxy powder at temperature of 185‐195°C, were nearly the same as those of a 3LPE coating that had been applied at the normal coating temperature (200‐230°C).

Originality/value

Recommended acceptance criteria for 3LPE coatings applied at 185‐195°C are proposed. The research results met the requirements for external anti‐corrosion properties for X80 longitudinally welded pipe.

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Article
Publication date: 8 January 2019

Luis Ricardo Jacobo, Rafael Garcia, Victor Hugo Lopez and Antonio Contreras

The purpose of this paper is to study the effect of heat treatment (HT) applied to an API X60 steel in corrosion resistance and stress corrosion cracking (SCC…

Abstract

Purpose

The purpose of this paper is to study the effect of heat treatment (HT) applied to an API X60 steel in corrosion resistance and stress corrosion cracking (SCC) susceptibility through slow strain rate tests (SSRT) in NS4 solution and congenital water (CW) to assess external and internal SCC, respectively.

Design/methodology/approach

API X60 steel was heat treated at a temperature of 1,200°C for 30 min followed by water quenching. Specimens from this steel were machined according to NACE TM 198. SSRT were performed in a constant extension rate tests (CERT) machine at room temperature at a strain rate of 1 × 10–6 s–1. For this purpose, a glass cell was used. Corrosion behavior was evaluated through polarization curves (PCs).

Findings

The SCC index obtained from SSRT indicates that the steel heat treated could be susceptible to SCC in CW and NS4 solution; the mechanism of SCC was hydrogen embrittlement. Thus, CW may promote the SCC phenomenon in pipelines. HT improves the steel corrosion resistance. Higher corrosion rate (CR) was observed when the steel is exposed to CW. The corrosion process in X60 steel shows that the oxidation reaction in the anodic branch corresponds to an activation process, and the cathode branches reveal a diffusion process.

Originality/value

The purpose of the heat treatment applied to X60 steel was to generate a microstructure of acicular ferrite to improve the corrosion resistance and SCC behavior.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 7 November 2016

Tengwei Zhu, Feng Huang, Jing Liu, Qian Hu and Wei Li

This paper aims to investigate the atmospheric corrosion mechanism of structural materials to develop more advanced corrosion-control technologies and cost-reduction…

Abstract

Purpose

This paper aims to investigate the atmospheric corrosion mechanism of structural materials to develop more advanced corrosion-control technologies and cost-reduction strategies. As a second phase in steels, the non-metallic oxide inclusions are considered to not only affect the mechanical properties of steel but also the corrosion resistance of steel. So, an important research goal in this paper is to investigate the indoor accelerated corrosion kinetics of Q450NQR1 weathering steel, analyzing the galvanic polarity of different inclusions in electrochemical corrosion microcell between the inclusion and steel matrix and then elucidating the influence mechanism of inclusions on corrosion resistance of weathering steel.

Design/methodology/approach

Two methods of inclusion modification are usually used to improve the properties of weathering steel: one is calcium treatment on aluminum killed steel and the other one is rare earth (RE) modification. Wet/dry cyclic immersion corrosion test field emission scanning electron microscopy (FE-SEM) metallographic optical microscope.

Findings

The indoor accelerated corrosion kinetics of Q450NQR1 weathering steel could be divided into two stages with different log (thickness loss, D)-log (time, t) fitting functions, and the effect of inclusions on the corrosion resistance of Q450NQR1 weathering steel was only reflected in the initial stages of corrosion. The inclusions of CaS in Ca-modified test steel and RE oxides and sulfides in RE-modified test steel were preferentially dissolved in acid media, slowing down the corrosion rate of steel matrix, but the non-metallic inclusion Al2O3 may accelerate the corrosion rate of the steel matrix as a form of differential aeration corrosion.

Originality/value

The effects of inclusions on corrosion resistance of Q450NQR1 weathering steel was investigated by dry–wet cycle immersion test and FE-SEM. The effect of inclusions on the corrosion resistance of Q450NQR1weathering steel was only reflected in the initial stages of corrosion. The inclusions of CaS in Ca-modified test steel and rare earth (RE) oxides and sulfides in RE-modified test steel were preferentially dissolved in acid media, slowing down the corrosion rate of steel matrix, but the non-metallic inclusion Al2O3 may accelerate corrosion rate of the steel matrix as a form of differential aeration corrosion.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 28 January 2022

Luis Manuel Quej-Ake, Sergio García Jiménez, Hongbo Liu, J.L. Alamilla and Carlos Angeles-Chavez

The purpose of this paper is to study the corrosion process by examining the deterioration of X80 steel exposed to a real petroleum sample containing condensed hydrocarbon…

Abstract

Purpose

The purpose of this paper is to study the corrosion process by examining the deterioration of X80 steel exposed to a real petroleum sample containing condensed hydrocarbon plus oilfield-produced water, which were subjected to stimulated emulsions in flowing media at 50°C.

Design/methodology/approach

The impedance and polarization spectra were used to assess the aggressiveness of the petroleum sample and tried to find a washing process using condensed hydrocarbon with deionized water. Mössbauer technique was used to identify the phases in precipitated ions obtained during an oven-drying procedure of the oilfield produced water.

Findings

The emulsion, chloride, sulphur compounds, heavy metals and the use of a double hydrodynamic system were the most important factors affecting the corrosion of X80 steel. The corrosion rate of this steel increased when oilfield-produced water was stimulated by a double hydrodynamic system (4.56 mm/year). It was determined to be 7.66 mm/year and 4.01 mm/year when steel was exposed to a stimulated emulsion using the petroleum sample and condensed hydrocarbon with deionized water at 24 h, respectively, suggesting that a significant process of hydrocarbon washing could occur and a more corrosive solution was highlighted. Mössbauer results showed that the ions precipitates included the following phases at Wt.%: magnetite (20.0), greigeite (22.8), siderite (3.2), pyrite (2.9), marcasite (26.7) and mackinawite (24.4).

Originality/value

A stimulated hydrocarbon/water emulsions with a more homogeneous solution containing high concentrations of saline compounds and heavy metals were used to simulate the susceptibility to corrosion on the internal pipeline steels exposed to any type of immiscible liquids such as condensed hydrocarbon, or crude oil, containing water. A practical application of the presented research could provide a novel framework for understanding the internal corrosion in pipelines from the simulation of washed hydrocarbons after the stimulated emulsions that can be found in the field. Because more susceptibility to corrosion for pipeline steels would be expected at the end of the transportation of the fluid. It is possible to investigate the possible corrosion mechanisms by using a dried oilfield-produced water sample interacting with the pipeline steels.

Details

Anti-Corrosion Methods and Materials, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 31 January 2020

Hailing Li, Hongxia Wan, Shengrong Wang, Cuiwei Du and Dawei Zhang

This paper aims to investigate the effect of alternating current (AC) on corrosion, it is not yet clear about the exact mechanism of the corrosion induced by AC. Previous…

Abstract

Purpose

This paper aims to investigate the effect of alternating current (AC) on corrosion, it is not yet clear about the exact mechanism of the corrosion induced by AC. Previous reports indicated that AC corrosion was similar to the effect of continuous cathodic and anodic polarization on the corrosion process of the metals. Wan et al. studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution.

Design/methodology/approach

This study attempted to understand the AC-induced corrosion by imposing the half-cycle AC on the X80 pipeline steel in an acid bicarbonate solution. The AC corrosion mechanism was determined by weight loss and potentiodynamic polarization curve measurements, as well as surface characterization.

Findings

The results show that the positive half-cycle AC accelerated the uniform corrosion in the NaHCO3 solution, the negative half-cycle AC would decrease the uniform corrosion and local corrosion was increased and some Ca and Mg deposited on the surface of X80 steel, so the corrosion rate decreased by negative half-cycle AC. The corrosion product was composed of α-FeOOH under the application of positive half-cycle AC. The oxygen reduction led to a local increase of pH near the electrode surface and led to the formation of α-FeOOH, which enhanced the protectability of corrosion products.

Originality/value

Researchers studied the effect of negative half-wave AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in near-neutral solution. However, the AC behavior and corrosion mechanism in acid solution are unknown. So to make clear about the corrosion behavior of metals in different polarization states and the mechanism involved, diode technology was used to research the AC corrosion, half-wave AC was applied on the metals after the full-wave rectified.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 31 January 2020

JiaYu Zhou, Zili Li, JianGuo Liu, Xiao Xing, Gan Cui, ShouXin Zhang, Ran Cheng and YiShu Wang

The purpose of this paper is to quantify the influence of alternating current (AC) interference on hydrogen evolution reaction of X80 steel.

Abstract

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.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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