In order to solve the problem of pipeline erosion-corrosion under acidic conditions with different CO contents of natural gas hydrate (NGH), the influence of different pH values on the erosion corrosion of X80 steel under dynamic conditions was studied. The erosion and corrosion behavior of X80 pipeline steel in multiphase flow (0.5% sand + 3% NaCl aqueous solution) at different pH was studied by rotating a cylindrical electrode apparatus combined with the electrochemical method in this paper. By analyzing the electrochemical impedance spectroscopy of the Tafel curve, the results showed that under dynamic solid-liquid two-phase conditions, with the decrease of the pH value, the self-corrosion potential of X80 steel samples was positively shifted, and the corrosion current density showed a trend of gradually increase. When the pH value is 2.0-3.0, the ac impedance spectrum of X80 steel samples shows a reactance arc in the high-frequency region and an inductive reactance arc in the low-frequency region. With the increase of the pH value, the radius of the capacitance and resistance arc of the impedance spectrogram increases gradually, and the time of the Bode spectrogram is "half peak" in the low-frequency region. As the time constant increases, the impedance decreases and the phase angle decreases; the overall polarization resistance on the surface increased gradually and the corrosion rate decreased significantly. Therefore, the pH value of the content of NGH with different CO contents has obvious influence on the solid-liquid two-phase erosion corrosion of X80 steel. With the increase of the pH value, the corrosion resistance of X80 steel increases, the corrosion rate decreases, and the corrosion strength decreases.
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http://dx.doi.org/10.1021/acsomega.0c05392 | DOI Listing |
Materials (Basel)
December 2024
School of Materials Science & Engineering, Key Laboratory of Advanced Technologies of Materials (Ministry of Education), Southwest Jiaotong University, Chengdu 610031, China.
A nondestructive evaluation of the hydrogen damage of materials in a hydrogen environment is important for monitoring the running conditions of various pieces of equipment. In this work, a new thermostatic electrolytic hydrogenation in situ ultrasonic test system (In Situ TEH-UT) was developed. The system operates by combining cross-correlation delay estimation and frequency domain amplitude estimation and hence improves measurement accuracy with respect to ultrasonic propagation time and amplitude, allowing in situ ultrasonic evaluation of the hydrogen-charging process in X80 pipeline steel.
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science & Engineering, Southwest Jiaotong University, Chengdu 610031, China.
The residual stress significantly affects the operational safety of oil and gas pipelines. Traditional ultrasonic stress measurement methods require pipeline surface pretreatment, which reduces detection efficiency. EMAT, as a non-contact measurement method, shows promising applications for residual stress detection in oil and gas pipelines.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
Centre for Advanced Materials Joining (CAMJ), Department of Mechanical and Mechatronic Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Laser welding was performed using different filler wires, ER70S steel, commercially pure iron, and pure nickel filler, in the context of welding X80 pipeline steel to assess the microstructure and mechanical properties of the weld metal. Introducing an ER70S wire promoted acicular ferrite formation in the fusion zone, compared to a bainitic microstructure in an autogenous laser weld. The use of pure iron wire was considered as a potential strategy for reducing hardenability, as it led to the dilution of alloying elements in the fusion zone, increasing ferrite content and reducing weld metal hardness to a level compliant with API pipeline standards.
View Article and Find Full Text PDFBioelectrochemistry
February 2025
Corrosion and Protection Center, Northeastern University, Shenyang 110819, China.
Materials (Basel)
September 2024
School of Mechanical Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
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