The corrosion behavior and cracking susceptibility of the disbonded coating in the X80 steel pipeline by theoretical simulations and experimental measurements

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bo Zhao ◽  
Zhijuan Zhao ◽  
Dong Jin ◽  
Na Li ◽  
Linlin Liu ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Corrosion Behavior ◽  
Electrode Reaction ◽  
Experimental Measurements ◽  
Accelerated Corrosion ◽  
Steel Pipeline ◽  
Corrosion Reaction ◽  
X80 Steel ◽  
Disbonded Coating ◽  
Theoretical Simulations

Abstract The corrosion behavior and cracking susceptibility of the disbonded coating in the X80 steel pipeline were investigated by different methods. The oxygen content in the trapped solution decreased rapidly with the formation of an airtight disbonded area. The airtight system affected the electrode reaction process, resulting in the inhibition of corrosion in the center of the disbonded area and the more refined surface finish of the sample. The bottom of the disbonded area underwent a relatively intense and accelerated corrosion reaction controlled by the diffusion process. The cracking susceptibility of the X80 steel firstly decreased and then increased in the pointing direction.

scholarly journals Corrosion Behavior of X80 Pipe Steel under HVDC Interference in Sandy Soil

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 809 ◽  
Author(s):  
Runzhi Qin ◽  
Yanxia Du ◽  
Zitao Jiang ◽  
Xiuyun Wang ◽  
Anqing Fu ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Sandy Soil ◽  
Direct Current ◽  
Corrosion Mechanism ◽  
High Voltage Direct Current ◽  
Corrosion Reaction ◽  
Local Soil ◽  
X80 Steel ◽  
Remaining Time ◽  
Peak Value

With the development of high voltage direct current (HVDC) systems, some pipelines have been badly interfered. The corrosion mechanism of pipelines has not been clearly clarified. In this work, laboratory experiments were designed to study the corrosion behavior of X80 steel under HVDC interference in sandy soil. The corrosion rates were related to the change in direct current (DC) density, which experienced three stages in the interference process. As soon as high DC interference voltage was applied to the working electrode, the current density increased sharply to a peak value in a few seconds. It then decreased rapidly to a steady value over dozens of seconds. Finally, it remained steady for the remaining time. With the measurement of local soil properties, the change in DC density was attributed to the local soil temperature increment, the water content decrement, and the substantial growth in the soil spread resistance. Moreover, the parameters contribute to the corrosion reaction during the interference process. The corrosion products were characterized at different times of interference via Raman spectroscopy. Lepidocrocite was produced under high DC density and then transformed to hematite under low DC density. Based on the above, the corrosion model during HVDC interference is proposed.

Monitoring of Coating Disbondment by a Scanning Kelvin Probe Technique

2010 ◽  
Author(s):  
A. Q. Fu ◽  
Y. F. Cheng
Keyword(s):  
Corrosion Behavior ◽  
Immersion Time ◽  
Pipeline Steel ◽  
Oxygen Solubility ◽  
Kelvin Probe ◽  
Scanning Kelvin Probe ◽  
Corrosion Reaction ◽  
Solution Layer ◽  
Concentrated Solution ◽  
Disbonded Coating

The coating disbondment and corrosion of a X65 pipeline steel under coating were studied by scanning Kelvin probe (SKP) measurements. The effects of immersion time and wet-dry cycle on the Kelvin potential profile and the corrosion behavior of the steel were investigated. Kelvin potential measured on “intact” area is shifted negatively with time, indicating an increasing water uptake under the “intact” coating. There is a more negative Kelvin potential on disbonded area than that on “intact” area, which is attributed to corrosion reaction of steel occurring under the disbonded coating. During wet-dry cycle, the thickness of solution layer trapped under disbonded coating decreases due to evaporation of water, causing a negative shift of Kelvin potential. It is associated with the reduction of oxygen solubility in the concentrated solution during drying of electrolyte.

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.

CORROSION BEHAVIOR OF X80 STEEL IN YINGTAN SOIL SIMULATED SOLUTION UNDER DISBONDED COATING

2012 ◽  
Vol 48 (12) ◽  
pp. 1530 ◽  
Author(s):  
Bo ZHAO ◽  
Cuiwei DU ◽  
Zhiyong LIU ◽  
Xiaogang LI ◽  
Jike YANG ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
X80 Steel ◽  
Disbonded Coating

Flow-accelerated corrosion behavior of 13Cr stainless steel in a wet gas environment containing CO2

2018 ◽  
Vol 25 (7) ◽  
pp. 779-787 ◽  
Author(s):  
Yong Li ◽  
Min-dong Chen ◽  
Jian-kuan Li ◽  
Long-fei Song ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Behavior ◽  
Accelerated Corrosion ◽  
Wet Gas ◽  
Gas Environment ◽  
Flow Accelerated Corrosion

Accelerated corrosion behavior of weathering steel Q345qDNH for bridge in industrial atmosphere

2021 ◽  
Vol 306 ◽  
pp. 124864
Author(s):  
Jun-dong Fu ◽  
Shui Wan ◽  
Ying Yang ◽  
Qiang Su ◽  
Wen-wen Han ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Weathering Steel ◽  
Accelerated Corrosion ◽  
Industrial Atmosphere

Experimental Study on Corrosion of Multi-Component Thermal Fluid Thermal Recovery well Tube String

2020 ◽  
Vol 993 ◽  
pp. 1257-1264
Author(s):  
Zhen Li ◽  
Pei Qi Zhao ◽  
Cheng Hui Yang ◽  
Yin Lei Liu ◽  
Yin Chuan Ding ◽  
...  
Keyword(s):  
High Temperature ◽  
Partial Pressure ◽  
Corrosion Behavior ◽  
Corrosion Damage ◽  
Thermal Recovery ◽  
Corrosion Rates ◽  
Thermal Fluids ◽  
Service Period ◽  
Corrosion Reaction ◽  
The Stability

The thermal recovery well tube string is subjected to corrosion damage in multi-component gas aqueous solution during service period. Some severe damage such as thinning, perforation and even fracture of the pipe can have a serious impact on the stability and safety of the thermal recovery wells. In this paper, the high temperature and high pressure rotating sample reaction device is used to study the corrosion behavior of K55 casing steel and L80 tubing steel in high temperature environment of flowing multi-fluid. The results show the effects of O2 and CO2 concentration and temperature on pipe corrosion. Combining with the results of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses, we inferred the corrosion reaction process of tubes in different media and the corrosion behavior of two kinds of steel in the environment of multiple thermal fluids containing O2 and CO2 is clarified. Results show that the corrosion rates of K55 and L80 increase with the increase of O2 partial pressure and CO2 partial pressure, but the corrosion rates are positively correlated with temperature in oxygen-containing condition and negatively correlated with temperature in carbon dioxide-containing condition. The compactness of the corrosion product film has a large effect on the corrosion rate.

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