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.

Effects of Hydrogen on Electrochemical Behaviors of X80 Steel in Simulated Soil Solution

2011 ◽  
Vol 335-336 ◽  
pp. 468-473 ◽  
Author(s):  
Chuan He ◽  
Xu Chen ◽  
Yang Xu ◽  
Zhi Yong Liu
Keyword(s):  
Soil Solution ◽  
Current Density ◽  
Polarization Resistance ◽  
Pipeline Steel ◽  
Charge Transfer Resistance ◽  
X80 Pipeline Steel ◽  
Transfer Resistance ◽  
Hydrogen Charging ◽  
Charging Time ◽  
X80 Steel

X80 pipeline steel specimens were treated by electrochemical hydrogen charging under various current density and charging time. The polarization resistance and corrosion rate of X80 steel were analyzed in Yingtan simulated soil solution under the different hydrogen charging conditions. The results showed that hydrogen accelerated anodic dissolution and enhanced corrosion sensitivity. With hydrogen in the steel, the charge transfer resistance and polarization resistance decreased, double electric layer capacitor and corrosion current increased. The effects were enhanced with the increase of hydrogen charging time and current density.

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.

Quenching Temperature‘s Impact on the Microstructure and Mechanical Properties of X80 Pipeline Steel

2011 ◽  
Vol 308-310 ◽  
pp. 762-766
Author(s):  
Yong Jie Ma ◽  
Xi Lu Liu ◽  
Guang Liang Zhang
Keyword(s):  
Mechanical Properties ◽  
Pipeline Steel ◽  
X80 Pipeline Steel ◽  
Quenching Temperature ◽  
Austenite Grain ◽  
State Study ◽  
Lath Bainite ◽  
Small Needle ◽  
X80 Steel ◽  
Increased Strength

The state study on mechanical properties’ changes of X80 steel at different quenching temperature. The results showed that the quenching temperature is 1000 °C, X80 Austenite grain coarsening is serious, leading to the production of coarse lath bainite ferrite, resulting in increased strength of X80 steel, toughness and hardness of a serious reduction; When the quenching temperature is 930 °C, and assisted by the appropriate temperatures, can make the X80 steel the small needle-like ferrite-based organizations, to obtain good hardness, strength, ductility and toughness of the match.

scholarly journals Effect of DC Currents and Strain on Corrosion of X80 Steel in a Near-Neutral Environment

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1601
Author(s):  
Zeyu Ma ◽  
Wei Wu ◽  
Pengxiong Zhao ◽  
Yong Dan
Keyword(s):  
Electrochemical Impedance ◽  
Steel Corrosion ◽  
Open Circuit ◽  
Applied Strain ◽  
Stray Current ◽  
Corrosion Scale ◽  
Surface Analysis Techniques ◽  
Neutral Soil ◽  
X80 Steel ◽  
Current Densities

The corrosion behavior of X80 steel in a near-neutral soil-simulated solution under various DC stray currents and applied strains was investigated using electrochemical measurements (open circuit potential, linear polarization, and electrochemical impedance spectroscopy) and surface analysis techniques. Our results show that a DC stray current has a substantially greater effect on steel corrosion compared to applied strain. However, strain could slow down the corrosion rate in specific conditions by affecting the composition of corrosion products and the structure of the corrosion scale on the surface of the steel. Although the porosity of the corrosion scale of steel without an applied strain will increase with increasing DC currents, once strain is applied, the corrosion scale will become denser. Furthermore, both DC currents and strain can promote steel pitting, and the number and size of pitting holes will increase significantly with an increase in current densities.

scholarly journals Electrochemical Investigation of Corrosion of X80 Steel under Elastic and Plastic Tensile Stress in CO2 Environment

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 949 ◽  
Author(s):  
Wei Wu ◽  
Hailong Yin ◽  
Hao Zhang ◽  
Jia Kang ◽  
Yun Li ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Tensile Stress ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Open Circuit ◽  
Co2 Corrosion ◽  
X80 Pipeline Steel ◽  
X80 Steel ◽  
Co2 Environment

An investigation into the electrochemical corrosion behavior of X80 pipeline steel under different elastic and plastic tensile stress in a CO2-saturated NaCl solution has been carried out by using open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analysis techniques. The results show that the corrosion rate of X80 steel first increases and then slightly decreases with the increase of elastic tensile stress, whereas the corrosion rate sharply increases with the increase of plastic tensile stress. Both elastic and plastic tensile stress can enhance steel corrosion by improving the electrochemical activity of both anodic and cathodic reactions. Moreover, compared with elastic tensile stress, plastic tensile stress has a more significant effect. Furthermore, electrochemical reactions for CO2 corrosion and mechanoelectrochemical effect are used to reasonably explain the corrosion behavior of stressed X80 steel in CO2 environment.

Effect of Applied Potentials on Stress Corrosion Cracking Susceptibility of X80 Pipeline Steel in Simulated Soil Solution

2010 ◽  
Vol 146-147 ◽  
pp. 920-925 ◽  
Author(s):  
Yuan Cheng ◽  
Hong Ying Yu ◽  
Li Xin Zhang ◽  
Ying Wang ◽  
Xu Meng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Stress Corrosion ◽  
Soil Solution ◽  
Stress Corrosion Cracking ◽  
Pipeline Steel ◽  
Corrosion Cracking ◽  
X80 Pipeline Steel ◽  
X80 Steel ◽  
Scanning Electron

The stress corrosion cracking susceptibility of X80 pipeline steel was investigated in a simulated soil solution using slow strain rate tensile (SSRT) tests. The different potentials were applied in the tests. The fracture surfaces were observed using scanning electron microscopy (SEM). The X80 steel was susceptible to SCC in simulated solution. The SCC susceptibility had no apparent change with the anodic potentials applied. The fracture mechanism was anodic dissolution. However, the SCC susceptibility increased with the decrease of the cathodic potentials obviously. The cracking was induced by the Hydrogen diffusing into the metal.

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.

Effect of Potentials on Stress Corrosion Cracking of X80 Pipeline Steel in Simulated Soil Solution

2011 ◽  
Vol 197-198 ◽  
pp. 1549-1554 ◽  
Author(s):  
Yuan Cheng ◽  
Hong Ying Yu ◽  
Ying Wang ◽  
Xu Meng ◽  
Li Xin Zhang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Stress Corrosion ◽  
Soil Solution ◽  
Anodic Dissolution ◽  
Stress Corrosion Cracking ◽  
Fracture Mechanism ◽  
Pipeline Steel ◽  
Corrosion Cracking ◽  
X80 Pipeline Steel ◽  
X80 Steel

The stress corrosion cracking (SCC) susceptibility of X80 pipeline steel, which was used in the Second West-East Gas Pipeline, was investigated in simulated soil solution of Xinzhou in Hubei province of China. The SCC susceptibility was studied using the slow strain rate tensile (SSRT) tests in which different potentials were applied. The fracture surfaces were observed using SEM. X80 steel was susceptible to SCC in simulated solution. The SCC was not serious with the anodic potentials applied. The fracture mechanism was anodic dissolution. But the SCC was affected obviously with different cathodic potentials because of the different influence of the hydrogen.

Microstructure and Texture Comparison of an Acicular Ferrite Pipeline Steel with Different Hot Rolling Process

2011 ◽  
Vol 399-401 ◽  
pp. 264-267
Author(s):  
Hai Yan Wang ◽  
Hui Ping Ren ◽  
Le Han ◽  
Zi Li Jin ◽  
Hao Sun
Keyword(s):  
Hot Rolling ◽  
Acicular Ferrite ◽  
Pipeline Steel ◽  
Orientation Distribution ◽  
Rolling Process ◽  
X80 Pipeline Steel ◽  
Hot Rolling Process ◽  
X80 Steel ◽  
Hot Rolled ◽  
Electron Back Scattered Diffraction

Microstructure of X80 pipeline steel with different hot rolling process was compared using Optical microscopy (OM), Bulk X-ray texture and micro orientation analysis was carried out by Orientation distribution function (ODF) and Electron back-scattered diffraction (EBSD), to analyze the various texture components of the pipeline steels under two different rolling processes. The results show that the final microstructures under the two schedules both present typical acicular ferrite characteristic. On the other side, the corresponding textures were found mainly comprised of two fibers in the rolling and normal direction in hot rolled X80 steel plate, there were obvious {112} , {110} , and {111} fiber, which seemed to be related with the mechanical properties anisotropy. Therefore, the influences of the microstructure and texture on the anisotropy were also discussed in this paper.

scholarly journals Effect of Alternating Stray Current Density on Corrosion Behavior of X80 Steel under Disbonded Coating

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qing-Miao Ding ◽  
Yong-Xiang Qin ◽  
Tao Shen ◽  
Yu-ning Gao
Keyword(s):  
Corrosion Behavior ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Negative Deviation ◽  
Stray Current ◽  
Cathode Area ◽  
X80 Steel ◽  
Wire Beam Electrode ◽  
Disbonded Coating

In this paper, the effect of alternating stray current (AC) density on the corrosion behavior of X80 steel under disbonded coating was studied by electrochemical methods, wire beam electrode (WBE) technology, and surface observation technology. The results showed that under the interference of different AC densities, the corrosion potential of X80 steel under disbonded coating underwent negative deviation, and the degree of negative deviation increased with the increase of AC density. The corrosion current density of X80 steel under disbonded coating with the action of 0~100 A/m2 AC density had few differences. While the corrosion current density of X80 steel with the action of 200~300 A/m2 AC density increased and the corrosion current density was higher than that under low AC density. The cathode area of the wire beam electrode under disbonded coating is mainly distributed outside and the edge of the gap between disbonded coating and X80 steel, while the anode area is mainly distributed inside the gap.

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