Pipeline Steel Research Articles

RESISTANCE OF FERRITE-PERLITE STEEL TUBING BRANCH PIPE METAL TO DESTRUCTION IN HYDROGEN SULFIDE MEDIUM

This paper discusses the problems of resistance of the metal of the tubing branch pipe (tubing) to the process of its destruction in a medium containing hydrogen sulfide and when exposed to external forces. A 73х73 tubing nozzle made of 38G2SFA steel was selected as the material for research. The tubing fragment was destroyed during production well operation. To establish the reasons for the failure of the tubing nozzle, a visual inspection was carried out, tests were performed to assess the hardness and mechanical properties, the microstructure and microtexture of the metal were analyzed using scanning electron microscopy (SEM) methods. To analyze the nature of the distribution of introduced defects, the mutual orientation of structural components and crystallographic texture, studies were carried out by the method electron backscatter diffraction (EBSD). Studies of the suspended branch pipe, which does not have chemical protection, showed that the cause of its destruction was hydrogen sulfide stress corrosion cracking (SSCC) as a result of hydrogen embrittlement and the action of external tensile forces exceeding the yield strength of the metal. It was established that as a result of the interaction of hydrogen sulfide of the distilled product with the metal of the branch pipe, hydrogen embrittlement of the material of the branch pipe occurred. The process of hydrogen embrittlement of the fragment was proved by detecting hydrogen blisters in the metal microstructure and establishing the process of coalescence of neighboring inclusions. In addition, the results of the test to measure the hardness of the metal along the wall thickness further supported the hypothesis of hydrogen embrittlement of the tubing. EBSD analysis showed that the threaded part of the branch pipe is characterized by a small size of structural elements and an increased density of introduced defects (geometrically necessary dislocations), which are a promising site for the deposition of molecular hydrogen. It is concluded that reaching the limit concentration of molecular hydrogen reduces the binding energy of metal atoms and this process initiates the formation of pores. It has been established that the development of cracks along large-angle grain boundaries is facilitated, and small-angle and coincidence site lattice (Σ3, Σ5, Σ11 and Σ13b) grain boundaries are active barriers to crack propagation. It has been shown that by optimizing the elemental composition of steel, controlling the microstructure, crystallographic texture, as well as the type and state of grain boundaries, new pipeline steels can be produced that are more resistant to SSCC.

Influence of riboflavin on the corrosion of X80 pipeline steel by Sulfate reducing bacteria

The sulfate reducing bacteria(SRB) is commonly attached to the surface of buried pipeline steel, and the electron shuttle in the corrosion medium can promote the release of electrons from iron oxidation through the bacterial cell wall into the cytoplasm to accelerate the corrosion of anode iron. This study investigated the impact of riboflavin (RF) as an endogenous electron shuttle on the corrosion behavior of X80 pipeline steel in SRB system. The findings indicated that while the type of corrosion products remains unchanged in samples under SRB+10 mg l−1 RF system, there was an expansion in both area and depth of corrosion pits on the sample surface, resulting in a corrosion loss rate approximately 3 times higher than that observed in SRB system. Furthermore, the polarization resistance (Rp) value of the sample in SRB system is about 2 ∼ 5 times that of the sample in SRB+10 mg l−1 RF system. Additionally, the corrosion current density of X80 pipeline steel samples soaked in SRB and SRB +10 mg l−1 RF system for 14 days is 9.31 × 10-6 A·cm−2 and 1.28 × 10−5 A·cm−2, and the addition of 10 mg l−1 RF increases the corrosion current density of SRB system by about 37.49%. These results indicated that the reaction resistance of SRB-induced MIC in X80 pipeline steel was significantly reduced due to the presence of RF.

Simulation study on the dynamic response of X80 steel pipelines under explosive loads

Simulation study on the dynamic response of X80 steel pipelines under explosive loads

Effect of Temperature and Immersion Time on Corrosion of Pipeline Steel Caused by Sulfate-Reducing Bacteria

Effect of Temperature and Immersion Time on Corrosion of Pipeline Steel Caused by Sulfate-Reducing Bacteria

Quantitative Study on Hydrogen Concentration–Hydrogen Embrittlement Sensitivity of X80 Pipeline Steel Based on Hydrogen Permeation Kinetics

Quantitative Study on Hydrogen Concentration–Hydrogen Embrittlement Sensitivity of X80 Pipeline Steel Based on Hydrogen Permeation Kinetics

Numerical exploration of a fully mechanistic mathematical model of aqueous CO2 corrosion in steel pipelines

A numerical exploration of a comprehensive mechanistic aqueous carbon dioxide (CO2) corrosion model is conducted across a range of temperatures (273–313 K), CO2 partial pressures (0.1–1 bar), and bulk pHs (5–6.5). Contour plots are produced to examine the impact on corrosion rate, surface pH, and surface saturation index of iron carbonate (FeCO3). Two response patterns are identified depending upon the limiting behaviour of the system, with a transition from charge-transfer control to mass-transport control as temperature is increased and partial pressure is reduced. FeCO3 surface saturation shows a strong correlation with the release of Fe2+ and increase in bulk pH.

Optimizing hydrogen permeation properties of WS2-Ni composite coatings on pipeline steel for improved hydrogen protection

Tungsten disulfide (WS2) has broad applications due to its unique molecular structure and outstanding physicochemical properties. In particular, the physical barrier properties of WS2 make it suitable to act as barriers against hydrogen. Herein, WS2-Ni composite coatings are prepared by electrodeposition to mitigate hydrogen-induced damage of X70 pipeline steel. The influence of the WS2 concentration on the hydrogen resistance of coating is assessed by electrochemical hydrogen permeation test, hydrogen adsorption simulation, slow strain rate tensile test (SSRT), and fracture analysis. As the WS2 concentration increases, the distributions of WS2 in the coatings transition from sparse to uniform and then agglomeration, while the grain size of Ni decreases initially and then decreases. These microstructural changes impact the hydrogen adsorption sites and diffusion paths, leading to a non-linear relationship between the hydrogen permeation resistance and WS2 concentration. This similar concentration dependence is also observed from the hydrogen embrittlement (HE) resistance of coatings, suggesting that enhancing the hydrogen permeation resistance can improve the HE resistance. This study highlights the great potential of WS2 as an effective barrier against hydrogen permeation, and the results provide insights into the hydrogen protection mechanism of pipeline steel.

Corrosion behavior of X60 pipeline steel in the presence of Sulfate Reducing Bacteria cultured in seawater and mud from the East China Sea

Sulfate-reducing Bacteria (SRB) corrosion is a serious threat to the safety of marine pipelines.To reveal the influence of the corrosion behavior of X60 pipeline steel in the presence of SRB cultured in seawater and mud from the East China Sea The corrosion behavior of X60 pipeline steel was studied with weight loss measurements, microstructure and membrane composition analysis, electrochemical measurements The corrosion rate in sterile seawater is 0.11 mm/y, whereas, in SRB-infested seawater, it increases by 245 % to 0.38 mm/y. In sterile sea mud, the corrosion rate is 0.15 mm/y, but in SRB-infested sea mud, it increases by 87 % to 0.28 mm/y. In the corrosive environment of seawater and mud in the East China Sea, SRB significantly accelerates the microbial corrosion of X60 pipeline steel. These findings provide theoretical guidance for further research on SRB corrosion mechanisms and corrosion control of marine pipelines.

Effect of Microstructural Constituents on Hydrogen Embrittlement Resistance of API X60, X70, and X80 Pipeline Steels

This study describes how microstructural constituents affected the hydrogen embrittlement resistance of high-strength pipeline steels. The American Petroleum Institute (API) X60, X70, and X80 pipeline steels demonstrated complicated microstructure comprising polygonal ferrite (PF), acicular ferrite, granular bainite (GB), bainitic ferrite (BF), and secondary phases, e.g., the martensite-austenite (MA) constituent, and the volume fraction of the microstructures was dependent on alloying elements and processing conditions. To evaluate the hydrogen embrittlement resistance, a slow strain rate test (SSRT) was performed after electrochemical hydrogen charging. The SSRT results indicated that the X80 steel with the highest volume fraction of the MA constituent demonstrated relatively high yield strength but exhibited the lowest hydrogen embrittlement resistance because the MA constituent acted as a reversible hydrogen trap site.

Effect of dissolved oxygen on corrosion behavior and mechanism of X70 pipeline steel in simulated low temperature bentonite-containing alkaline chloride environment

Effect of dissolved oxygen (DO) on the corrosion behavior of X70 pipeline steel in low temperature bentonite-containing alkaline chloride environments was comprehensively investigated. The cathodic reduction reaction is inhibited and corrosion current density gradually descent as the DO decreases, resulting in a significant improvement in the corrosion resistance of X70 pipeline steel. The content of Fe3O4 and α-FeOOH in the corrosion products film increases, refinement of rust grains and crack decreases effectively suppressing the penetration of corrosive substances. Pitting initiates within ferrite grains and at phase interface, while reducing the DO can restrain the chemical dissolution of MnS to retard the pit initiation.

Electroactive Shewanella algae accelerates the crevice corrosion of X70 pipeline steel in marine environment

Crevice corrosion causes severe damage to metallic materials in marine environments. The inner mechanism of crevice corrosion in the presence of microbes deserves in-depth investigation. Herein, the electroactive Shewanella algae was found to accelerate the crevice corrosion of X70 pipeline steel through weight loss analysis, electrochemical tests, characterization of surface morphology, and analysis of corrosion products. The corrosion current increased to 2.3 μA cm−2, which was 2.3 folds of that in a sterile medium. Further electrochemical tests were carried out with exogenous addition of riboflavin. It confirmed that extracellular electron transfer accelerated the crevice corrosion in which S. algae participated.

Characterizing pearlite transformation in an API X60 pipeline steel through phase-field modeling and experimental validation

This study explores the microstructural characterization of pearlite phase transformation in high-strength low-alloy API X60 steel, which is used in pipelines. Understanding the formation, phase percentages, and morphology of the pearlitic phase is crucial since it affects the mechanical properties of the considered steel. In this research, a phase-field model, particularly the Cahn–Hilliard approach, was used in order to simulate the formation and morphology of the pearlite phase in response to different heat treatments. Both double- and triple-well potentials were considered for comprehensively studying pearlite’s morphology in the simulations. The simulation results were then compared with experimental outcomes obtained by metallography and field-emission scanning electron microscopy analyses. Considering the double-well potential can help simulate only two phases, ferrite and cementite, which is less compatible with the experiment results than the triple-well potential, which gives the possibility of simulating a three-phase microstructure, ferrite, cementite, and austenite, and a better match with experimental data. The study revealed that as the cooling rate increases, the interlamellar spacing and layer thickness decrease. Additionally, the difference between experimental and simulation results using triple-well potential was approximately ∼10%. Therefore, triple-well potential formulation predictions have better agreements with experimental results for the development circumstance of pearlitic structures.

Investigation of sigma phase generated by simulated welding heat treatment on corrosion behavior of 2205 hydraulic control pipeline steel

Duplex stainless steel (DSS) hydraulic control pipelines readily form sigma phase during the heat treatment process, reducing corrosion resistance and leading to pipeline leakage and failure. This study employs various analysis methods to investigate the effect of sigma phase on the corrosion behavior of 2205 hydraulic control pipeline steel, focusing on the electronic characterization of passive film and pitting corrosion behavior. Results revealed that the sigma phase content reaches a maximum value of 13 % at 850 °C within the heat treatment temperature range of 750–950 °C. The voltaic potential of the sigma phase is approximately 47 mV higher than the matrix, but the Cr-depleted zone around the sigma phase is about 85 mV lower than the matrix. The passive film of specimens containing sigma phase exhibits higher carrier densities and lower content of Cr(OH)3 and Cr2O3 compared to as-received specimens. The morphologies of the film show obvious groove defects, which provide a corrosion channel to the matrix. Moreover, specimens containing sigma phase exhibit higher intergranular corrosion susceptibility and lower pitting corrosion resistance. Pits preferentially nucleate and develop in the Cr-depleted zone around the sigma phase, with their quantity and size positively correlated with the sigma phase content.

Improving anti-corrosion and mechanical properties of mild steel pipelines by using polyurea with nanoparticles

ASTM A106 B grade is used to manufacture seamless steel pipe, which can be used at high temperature, pressure, and hard environmental conditions for oil and gas supplies but suffers from corrosion. Polyurea is an organic coating that is resistant to moisture, UV light, and chemicals and has a high range of service temperatures. In this study, the effect of polyurea coating with the addition of copper nanoparticles was investigated for improvement of anti-corrosion and mechanical behavior in 3.5 % NaCl solution for A106 steel. Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) tests were performed to examine anticorrosion properties, Scanning Electron Microscopy (SEM) was used to examine quality coating, thickness, and distribution of copper nanoparticles. Wear, hardness, and tensile tests were performed to check mechanical properties. The corrosion rate decreases from 0.16264 mpy to 0.01376 mpy while coating resistance increases from 2.95 × 104 Ω cm2 to 2.474 × 105 Ω cm2. An increasing trend was observed during the tensile test for pure polyurea and pure polyurea with 2 % copper nanoparticles. i.e., 501 MPa and 536 MPa, respectively. Results showed pure polyurea and polyurea with copper nanoparticles on steel improve its anti-corrosion and mechanical properties significantly.

Understanding and probing progression of localized corrosion on inner walls of steel pipelines: an overview

Understanding and probing progression of localized corrosion on inner walls of steel pipelines: an overview

Machine learning-based Shapley additive explanations approach for corroded pipeline failure mode identification

Rapid failure mode identification of oil and gas pipelines can prevent catastrophic consequences, improve fast intervention and enhance the design safety of these critical systems. This paper proposes explainable-based machine learning models using to determine the failure mode of corroded pipelines as a function of geometric configurations, material properties, and corrosion defect details. To determine the best identification model, this study examined eight machine learning models, including Nave Bayes, K-Nearest Neighbors, Decision Tree, Random Forest, Adaptive Boosting, Extreme Gradient Boosting, Light Gradient Boosting Machine, and Category Boosting, based on a comprehensive experimental database for steel pipelines with various corrosion/crack defect configurations. Furthermore, the Shapley additive explanations approach is utilized to rank the input variables for failure mode identification and explains the machine learning model predicting a specific failure mode for a given sample. In identifying the failure mode of corroded pipelines, the proposed Extreme Gradient Boosting model indicated the highest accuracy in term of performance evaluation compared to all other proposed models. In addition, the model-explanation findings show that the important parameter influencing the failure mechanism of corroded pipelines is the depth of corrosion defects followed by the pipeline wall thickness. The proposed framework is adaptable enough to allow further use of experimental results for having new insights.

Feature extraction method for ultrasonic pipeline defects based on fractional-order VMD

ABSTRACT Ensuring the safety of pipeline transportation is vital for societal well-being. Traditional methods for identifying defects in steel pipelines through ultrasonic echo signal pattern recognition often fail to extract comprehensive and effective features crucial for accurate defect detection. This study introduces an innovative feature extraction method employing a fractional Fourier transform variational modal decomposition (FRFT-VMD), hereafter referred to as the fractional-order VMD algorithm. This method utilises the fourth-order central moment and envelope entropy to optimise several key parameters: the fractional order in the Fourier transform, the number of decomposition layers, and the penalty factor in variational modal decomposition. To evaluate the effectiveness of the proposed method, ultrasonic echo signals from both finite element simulations and experimental platforms were analysed using the FRFT-VMD technique. The features extracted were then classified using a Least Squares Support Vector Machine (LSSVM) to determine defect depths. The results show a recognition accuracy of 95.2% in simulated signals and 89.1% in experimentally measured signals across various defect depths, indicating a significant improvement over existing feature extraction methodologies. The fractional-order VMD algorithm proves to be superior in extracting features that enhance the accuracy of defect identification in steel pipelines.

Hydrogen-induced cracking of longitudinally submerged arc welded HSLA API 5L X65 carbon steel pipeline

This study investigates the hydrogen-induced cracking (HIC) of a thermomechanical controlled processed (TMCP) API 5L X65 steel pipe fabricated using the JCOE forming process. Despite passing HIC testing as a plate, the final pipe exhibited unexpected failure, highlighting the critical influence of pipe fabrication on material performance. In this study, failed pipes were subjected to heat treatment, and HIC testing following NACE TM 0284 standard, SEM, and EDX examinations. The effect of heat treatment on the grain size, residual stress and susceptibility to HIC was investigated. The findings revealed that welding played a detrimental role, as all the HIC failures occurred at the welded area (0° orientation) due to welding-induced stresses and potential microstructural changes. It is believed that the welding process imposed reversible hydrogen traps in the HIC resistance plate ultimately reducing the HIC resistance. The heat treatment proved an effective method for relieving the applied micro-residual stresses that resulted in enhanced HIC resistance of the material.

Penetration of imidazoline derivatives through deposited scale for inhibiting the under-deposit corrosion of pipeline steel

Effective penetration of corrosion inhibitors through deposits is vital for controlling under-deposit corrosion (UDC) in oil/gas production. Herein, the penetration of three imidazoline derivatives across a CaCO3-based scale in CO2-saturated brine was examined, along with the resulting protection effect on mild steel. Real-time spectral monitoring revealed the correlation between inhibitor structures and penetration ability, with a maximum permeability of 24.1 %. Imidazoline's affinity with water, indicated by coordination number, significantly influenced the penetration. The intrinsic efficacy of imidazoline derivatives determined actual UDC inhibition efficiency, reaching a maximum of 92.33 %, under conditions of sufficient penetration.

Seismic fragility analysis of buried pipelines under Kahramanmaraş ground motions

This paper aims to evaluate the failure probability of buried pipelines under pulse-like ground motions based on the seismic records detected during the Kahramanmaraş earthquake in Turkey. The incremental dynamic analysis (IDA) method was used to evaluate the vulnerability of continuous and segmented steel pipes, taking into account the corrosion effect in alkaline and near-neutral soil environments.The results show that pulse-like ground motion can significantly impact the fragility of buried pipelines, particularly segment steel pipelines. Moreover, the failure probability of buried pipelines tends to increase with service age, although the rate of failure gradually decreases. Empirical models notably underestimate the failure probability of buried pipelines under pulse-like ground motion, so they should be used cautiously in engineering application. These insights contribute to advancing our understanding of the seismic fragility of buried pipelines.