Steel API 5L Research Articles

Facile fabrication of ZnO nanoparticles via non-thermal plasma technique and their anti-corrosive effects on X60 API 5L steel in 1M HCl solution

This work aims to explore the efficiency of ZnO nanoparticles synthesized via the non-thermal gliding arc discharge-assisted plasma (NT-GAD) technique for inhibiting the corrosion of X60 API 5L steel in a 1M HCl environment. The XRD pattern revealed that the ZnO nanoparticles exhibit hexagonal wurtzite structure with average particle size of ∼24 nm. UV–visible spectroscopy analysis revealed an absorption peak centering at 365 nm, corresponding to an energy band gap of 3.29 eV. SEM and TEM analysis revealed that the nanoparticles exhibit an agglomerated and irregular morphology. The corrosion inhibition of ZnO NPs was investigated via the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests (PDP), while varying both concentration and temperature. The results revealed that the increase in inhibitor concentration resulted in a higher activity at ambient temperature, with an optimal efficiency of 93 % at a concentration of 100 mg/L. However, the increase in temperature remarkably reduced the inhibition efficiency, suggesting a physisorption behavior of ZnO NPs onto the steel surface. AFM and FE-SEM analysis confirmed the formation of a protective layer on the X60 API 5L steel surface. This study emphasizes the significant potential of ZnO NPs synthesized via the NT-GAD assisted plasma technique as corrosion inhibitor for X60 API 5L carbon steel in 1M HCl corrosive media.

Hydrogen embrittlement effects on remaining life and fatigue crack growth rate in API 5L X52 steel pipelines under cyclic pressure loading

Transporting hydrogen gas through the existing natural gas pipeline network offers an efficient solution for energy storage and conveyance. Hydrogen generated from excess renewable electricity can be conveyed through the API 5L steel-made pipelines that already exist. In recent years, there has been a growing demand for the transportation of hydrogen through existing gas pipelines. Therefore, numerical and experimental tests are required to verify and ensure the mechanical integrity of the API 5L steel pipelines that will be used for pressurized hydrogen transportation. Internal pressure loading is likely to accelerate hydrogen diffusion through the internal pipe wall and consequently accentuate the hydrogen embrittlement of steel pipelines. Furthermore, pre-cracked pipelines are susceptible to quick failure mainly under a time-dependent cyclic pressure loading that drives fatigue crack propagation. Meanwhile, after several loading cycles, the initial cracks will propagate to a critical size. At this point, the remaining service life of the pipeline can be estimated, and inspection intervals can be determined. This paper focuses on the hydrogen embrittlement of API 5L steel-made pipeline under cyclic pressure loading. Pressurized hydrogen gas is transported through a network of pipelines where demands at consumption nodes vary periodically. The resulting pressure profile over time is considered a cyclic loading on the internal wall of a pre-cracked pipeline made of API 5L steel-grade material. Numerical modeling has allowed the prediction of fatigue crack evolution and estimation of the remaining service life of the pipeline. The developed methodology presented in this paper is based on the ASME B31.12 standard, which outlines the guidelines for hydrogen pipelines with reference to the ASME BPVC Section VIII, Division 3, Article KD-10.

Unveiling green corrosion inhibitor of Aloe vera extracts for API 5L steel in seawater environment

This study evaluated Aloe vera extract as a green inhibitor to prevent corrosion in seawater environments. A. vera extract was produced by maceration with methanol–water at room temperature. Electrochemical techniques were used to evaluate the corrosion inhibitor effectiveness of the A. vera extract. The morphology of the corrosion products was analyzed by FE-SEM equipped with EDS and AFM. FT-IR and LCMS characterized the functional and structural groups in this extract. The electrochemical measurements show that A. vera extract could effectively reduce the corrosion of API 5L steel in seawater environments. Inhibition efficiency (IE) increases with increasing concentration. Optimal corrosion inhibition efficiency of around 83.75% (PDP) and 88.60% (EIS) was obtained by adding 300 mg L−1 of extract at 310 K. Furthermore, the higher the concentration of A. vera extract, the greater the activation energy (Ea), with the highest activation energy being 48.24 kJ mol−1 for the concentration of 300 mg L−1. Conversely, increasing the temperature and exposure duration reduces the corrosion inhibition efficiency (IE) values; the best exposure period was 30 min with 88.34% IE by a concentration of 300 mg L−1 at 300 K. This corrosion inhibition is achieved by the adsorption process of A. vera bioactive on metal surfaces with a mixed inhibitor through a physisorption-chemisorption mechanism. This finding was confirmed by the smoother surface morphology of the steel treated with A. vera extract than without. This unveiling investigation found that A. vera extract has the potential to be an environmentally friendly corrosion inhibitor in the seawater environment.

Plastic behavior and shakedown limit of defected pressurized pipe under cyclic bending moment

Pipelines subjected to thermal or mechanical loads may fail due to plastic strain accumulation which leads to ratcheting. In this research, cyclic plastic behavior and shakedown limit are investigated experimentally and numerically for a defected pressurized pipe under cyclic bending moment. In the numerical model, the combined isotropic/kinematic hardening model based on the Chaboche model is adopted to represent the cyclic plastic flow of the material. The hardening parameters are determined experimentally and used in the finite element (FE) model. A four-point bending test rig is manufactured to test a pressurized API 5L steel pipe under cyclic bending. An elliptical defect is created by machining to depict corrosion pits in pipes. The plastic strains are measured experimentally and the results are used to tune the parameters of the FE model. The shakedown limit of the defected pipe is determined numerically by tracking the critical points behavior and the results are verified experimentally. Furthermore, the plastic work dissipated energy (PWD) is estimated within the defective structure to study the behavior of the pipe. By running this compatible model, it is found that the yield and the shakedown limits are lowered by mean values of 55% and 25% respectively due to the presence of metal loss defect occupying almost half of the pipe thickness.

Effectiveness of Red Dragon Fruit Peel Extract as an Eco-Friendly Corrosion Inhibitor for API 5L Steel

The development of organic or natural inhibitors is essential due to their cost-effectiveness and eco-friendliness. In this study, an organic inhibitor derived from red dragon fruit peel waste is employed. The material of interest is heat-treated API 5L Grade B steel. The research assesses the inhibitor’s efficiency in corrosive environments, namely 3.5‰ NaCl solution and pH 3 HCl solution, with varying inhibitor concentrations (5 ppm, 10 ppm, 15 ppm, 20 ppm). Using Tafel analysis and Electrochemical Impedance Spectroscopy (EIS), it is found that the addition of red dragon fruit peel extract substantially reduces the corrosion rate. The highest efficiency is observed in the 3.5‰ NaCl solution (62.4%) and pH 3 HCl solution (87.73%), accompanied by charge transfer resistances of 2.47 x 106 Ω and 1.79 x 103 Ω, respectively. Immersion tests reveal corrosion products, subsequently examined using X-ray Diffraction (XRD) to identify lepidocrocite phases in the 3.5‰ NaCl solution and magnetite phases in the pH 3 HCl solution. This research supports the development of environmentally friendly and effective natural corrosion inhibitors for protecting steel materials in corrosive conditions.

Effect of pulsed current cathodic protection on pipeline steel API 5L X65 corrosion mitigation: An investigation and machine learning-assisted modeling

Pulsed current cathodic protection (PCCP) could be more effective than direct current cathodic protection (DCCP) for mitigating corrosion in buried structures in the oil and gas industries if appropriate pulsed parameters are chosen. The purpose of this research is to present the corrosion prevention mechanism of the PCCP technique by taking into account the effects of duty cycle as well as frequency, modeling the relationships between pulse parameters (frequency and duty cycle) and system outputs (corrosion rate, protective current and pipe-to-soil potential) and finally identifying the most effective protection conditions over a wide range of frequency (2–10 kHz) and duty cycle (25%-75%). For this, pipe-to-soil potential, pH, current and power consumption, corrosion rate, surface deposits and investigation of pitting corrosion were taken into account. To model the input-output relationship in the PCCP method, a data-driven machine learning approach was used by training an artificial neural network (ANN). The results revealed that the PCCP system could yield the best protection conditions at 10 kHz frequency and 50% duty cycle, resulting in the longest protection length with the lowest corrosion rate at a consumption current 0.3 time that of the DCCP method. In the frequency range of 6–10 kHz and duty cycles of 50%-75%, SEM images indicated a uniform distribution of calcite deposits and no pits on cathode surface.

PROTEKSI KOROSI PADA BAJA API 5L DENGAN INHIBITOR ORGANIK EKSTRAK DAUN BAWANG DAYAK (Eleutherme Americana Merr) DALAM LINGKUNGAN HCL 0,5 M

Corrosion is a decrease in metal quality due to an electrochemical reaction with its environment. Many factors can cause corrosion of a material. One of them is due to the influence of the concentration of chloride acid dissolved in water media so that the environment is corrosive (acidic). Corrosion can occur in various forms, ranging from uniform corrosion on the entire metal surface to corrosion that is concentrated in certain parts. There are many methods to inhibit the corrosion process. One of the many methods is the use of inhibitors. Organic inhibitor is a type of inhibitor that is non-toxic, inexpensive, readily available in nature, easy to renew and does not damage the environment. These organic inhibitors are obtained by extracting some materials that exist in nature. In this study, the inhibitor used was Dayak leek. The inhibitor is used on API 5L steel material in 0.5M HCl media. The method used to retrieve the steel corrosion rate data using the weight loss method. The inhibition efficiency reached 99.02% for the addition of an inhibitor with a concentration of 5% with an immersion time of 10 days with a corrosion rate of 4.46 mpy.

Effect of syzygium cumini leaf extract as a green corrosion inhibitor on API 5l carbon steel in 1M HCL

Corrosion in API 5L steel under 1M HCl is a common issue; hence, creating a more effective and naturally-based inhibitor is critical. In this research, Syzygium Cumini leaf extract (SCLE) was used as a new green corrosion inhibitor under acidic conditions. The inhibition properties of the novel cumini extract were thoroughly characterized using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). The results show that the cumini inhibitor has excellent corrosion inhibition with 93 % inhibition efficiency. The adsorption behavior of the inhibitor follows the Langmuir Adsorption Isotherm due to the nearness of R2 to unity. The potentiodynamic and electrochemical measurements demonstrate the mixed type of corrosion inhibitor. Thermodynamic calculation of ΔGads is – 18.41 kJ mol-1 showing the physical adsorption process between the inhibitor and metals. Further inspection of ΔHads at ‒58.93 kJ mol-1 considers releasing energy during adsorption. The FTIR results agree with the increased growth of passive layers due to the adsorption of polyphenol and flavonoids on metals. Remarkably, the adsorption peak at 3266.59 cm-1 corresponds to the adsorption of –OH. The peak at 1612.56 and 1698.4 cm-1 is attributed to C=C and C=O functional groups. The above functional groups serve as adsorption centers to reduce the corrosion effect. The surface treatment of AFM indicated a good relationship with the functional group characterization and confirmed the significant corrosion rate reduction. This work can be used as a benchmark to develop a natural plant as a corrosion inhibitor.

Hardening mechanisms in a high wall thickness sour service pipe steel API 5L X65 before and after post-welding heat treatments

The strength of the pipe region opposite to the weld in a high wall thickness sour service pipeline steel API 5L X65, manufactured by the SAW UOE process, has been studied in detail. The fundamental hardening mechanisms that contribute to the yield strength of this pipe portion were determined according to its microstructural features before and after post-weld stress relieving heat treatment. The root mean square summation of the different strengthening mechanisms resulted in a reasonable estimate of the yield strength of this pipe portion before the heat treatment. The contributions of the different strengthening mechanisms proceeded at different length scales in this pipe portion before and after the heat treatment. The heat treatment at 650 °C (1.5 h) reduced the contributions of the strengthening mechanisms to the steel yield strength corresponding to this pipe portion. The dislocation strengthening contribution decreased by approximately 50%. The precipitation hardening and the solid solution and grain size strengthening reduced their contributions by approximately 14% and 3% respectively.

Symmetric spherical surface harmonics for predicting average pitting corrosion susceptibility index of carbon steels from EBSD microtexture measurements

This work presents a study on the correlation between the crystallographic texture and the pitting corrosion susceptibility of API 5L steels. The crystallographic textures of API 5L steel samples (codified as S1, S2, S3, and S4) were studied using EBSD measurements. A deterministic model based on symmetric spherical surface harmonics was proposed to describe the strong dependence of the pitting corrosion susceptibility on the crystallographic (grains) orientation of the (body-centered cubic) material. Using the model, pitting corrosion susceptibility index values estimated from EBSD raw data agreed in relative magnitudes (from sample to sample) with the predictions made from X-ray macrotexture measurements, and the results derived from other techniques such as cyclic polarization tests and analyses of SEM and AFM images. This agreement verified the capacity of EBSD to estimate the pitting corrosion susceptibility indices of carbon steels having different microstructures and textures, which were found to be 0.60, 0.53, 0.51, and 0.44 for S1, S2, S3, and S4, respectively. It was established that the higher the values of pitting corrosion susceptibility indices, the higher the tendency to present pitting corrosion of the material; thus, S1>S2>S3>S4. Moreover, the results have shown that the crystallographic texture plays a more decisive role in the behaviour of pitting corrosion in carbon steels compared to other microstructural and chemical parameters such as the grain size and inclusion content. The proposed (deterministic) model could be a novel tool for predicting pitting corrosion of the material, forming part of a novel method for the material selection process.

The Study of Mixing Purple Sweet Potato and Turmeric Extract as Green Corrosion Inhibitor for API-5L in NaCl 3,5% Environment

Green inhibitors have become a major option for corrosion prevention since people are more aware of environmental damage. It is true that chemical inhibitors are more powerful at preventing corrosion, but its side effects are very harmful to the environment. Purple sweet potato (Ipomoea batatas L) in single use has been proven as an active inhibitor for certain applications. To improve this property, purple sweet potato is used as a mixed with other plants that contain antioxidant agents, such as ginger, melinjo, turmeric, jeera, etc. This paper discussed the effect of applying mixed extract of purple sweet potato with turmeric (Curcuma longa) as a green inhibitor to corrosion rate of API 5L steel in a 3.5% NaCl environment. Turmeric extract contains curcumin and kaempferol antioxidants while purple sweet potato extract contains antocyanin antioxidants. Corrosion rates were analyzed based on weight loss and polarization methods. The results showed the highest inhibitor efficiency was 82.54% achieved by 16 ml of turmeric mixed with 2 ml of purple sweet potato, and the optimum inhibitor efficiency was 74.2% achieved by 8 ml of turmeric mixed with 6 ml of purple sweet potato.

Non-metallic inclusions interpretation technique for factory expertise of metal product defects

The technique of processing the results of factory experts’ reports has been developed to interpret the origin of nonmetallic inclusions (NMIs) detected in the defects of a welded pipe joints made of J55 API 5L (22GYu) steel. Thermodynamic simulation was performed to assess the possibility of the indigenous origin of these inclusions. The results of such a simulation were summarized using radar diagrams of four clusters uniting NMIs with similar composition of deoxidation and modification products. More than 130 compositions of actual inclusions detected on dozens of welded joints samples were processed and combined into four clusters in the same way. After a comparative analysis of these two types of radar diagrams, the origin of all clusters of actual inclusions was established, three of which are predominantly exogenous inclusions and the fourth is predominantly indigenous. None of the clusters contains only indigenous inclusions or only exogenous ones. The main source of inclusions in the discontinuities of welded joints is inclusions conglomerates, sorbed on the refractories surface, contacted with molten steel during its ladle treatment and pouring. These sintered conglomerates of indigenous and exogenous inclusions, that form three clusters of four ones, were out washed by the flow of steel melt into the crystallizer during steel pouring. The reasons for the formation of the fourth cluster are related to “cold welding”. The technique is implemented as a plug-in of Thixomet Pro image analysis system and allows to automate the process of metallographic conclusions generation in factory practice, as well as to accumulate all information in a database for its subsequent processing and analysis.

Numerical Analysis of Single Edge Notched Tension Specimen With Fatigue Crack Parameter of Conventional Specimen Using Linear Elastic Fracture Mechanics

This paper describes the numerical analysis of planar crack growth in high strength steel API 5L X70 whose crack growth parameter is adopted from experimental compact tension (CT) specimen in previous literature. Apart from the fact that conventional fatigue crack growth specimen has bogus geometry constraints, the Single Edge Notched Tension (SENT) better replicate the crack-tip constraint conditions experienced in structures. Linear elastic fracture mechanics (LEFM) crack orientation is modelled with the finite element method in SENT model considering its geometry functions a/W ratio to determine its crack growth rate based on constant amplitude load. The virtual crack closure technique tool in MSC Marc/Mentat software with adaptive and global remeshing is applied to assess high cycle fatigue crack propagation using the SENT model. The crack growth pattern for the 3-dimensional simulation characteristics is similar with that of the CT Specimen experimental procedure. Furthermore, the results of the crack propagation and the cycle count demonstrated good agreement with bearable discrepancy with maximum percentage difference of about 14.1 % for the HAZ and 6.4% for the weld and parent metal compared to the experimental resultsfrom literature.

The Theoretical Investigations and Molecular Dynamic Stimulation of Isoniazid as a Corrosion Inhibitor

API5L Steel is known as one of the most useful materials on earth which is also subject to corrosion in certain environments. Many methods have been used to minimize its corrosion, but the use of inhibitors is widely accepted. The use of green inhibitors has gained wide usage because of their environmental friendliness. The theoretical investigations of isoniazid as corrosion inhibitor was carried out using Fourier transform infrared spectroscopy (FTIR), whereas theoretically, quantum chemical parameters and molecular dynamic simulations of the inhibitor were studied. The analyses of the experimental results showed that the expired drug (isoniazid) decreased the corrosion rate of API5L steel in a 0.5M H2SO4 medium. The inhibition efficiency decreased with a decrease in inhibitor concentration. FTIR results showed that the inhibition mechanism is physical through the functional groups present in the expired drug. Relying on quantum chemical parameters and molecular dynamic simulations results, the adsorption/binding strength of the concerned inhibitor molecule on API5L steel surface follows a good order. The computed adsorption/binding energy values (Eads) for the various isolated concentrations from the inhibitor indicate the adsorption process to be non-covalent (physiosorption) which is in good agreement with the literature.

Influence of Acidification and Warming of Seawater on Biofouling by Bacteria Grown over API 5L Steel.

The online version contains supplementary material available at 10.1007/s12088-021-00925-7.

The oil spill and the use of chemical surfactant reduce microbial corrosion on API 5L steel buried in saline soil.

In order to evaluate the biocorrosion of API 5L metal buried in saline soils, three different conditions in microcosms were evaluated. The control microcosm contained only saline soil, the second had the addition of petroleum, and the third contained the addition of both petroleum and surfactant. The corrosion rate of the metals was measured by loss of mass after 30 days, and the microbial communities were delineated using 16S rRNA gene sequencing techniques. The species were dominated by halophiles in all samples analyzed. Among the bacteria, the predominant group was Proteobacteria, with emphasis on the Alphaproteobacteria and Gammaproteobacteria. Betaproteobacteria and Deltaproteobacteria members were also identified in a smaller number in all conditions. Firmicutes were especially abundant in the control system, although it was persistently present in other conditions evaluated. Bacteroidetes and Actinobacteria were also present in a considerable number of OTUs in the three microcosms. Halobacteria were predominant among archaea and were present in all conditions. The analysis pointed to a conclusion that in the control microcosm, the corrosion rate was higher, while the microcosm containing only oil had the lowest corrosion rate. These results suggest that, under these conditions, the entry of other carbon sources favors the presence of petroleum degraders, rather than samples involved in the corrosion of metals.

Research on the nondestructive examination of narrow gap MAG welding of API 5L X65M thermomechanical treated steel

The thermomechanical treated steel API 5L X65, is the candidate material for the execution of underground and submarine pipelines having a diameter of 42″(1066.8 mm) and a wall thickness of 31.75 mm which are intended for oil and gas transport. The welding was realized by MAG welding in spray arc for the root layer and in pulsed current for filling the joint. The selected welding filler metal were ER 70S-G wire for the root welding and the E70S-6 wire for the fill layers. The pursued objective in the present paper aims at the non-destructive evaluation of the quality of welded joints using methods of visual, magnetic particle and radiographic examinations. The information resulting from the investigation of defects such as porosity, lack of fusing and incomplete penetration at the root pass showed that the welding joints made using the technological parameters established as optimal through experiments are in compliance with the quality requirements imposed by the code API 1104 – 2013.

HIC and SSC of Carbon Steel in High Partial Pressure CO2 Environments with Elevated H2S

The Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC) behaviours of sour service and non-sour service carbon steel API 5L X65 were investigated under high pressure carbon dioxide environments, containing elevated amount of hydrogen sulphide (H2S); the test environments simulated offshore pipelines transporting full-well streams in high carbon dioxide (CO2) environments with elevated H2S concentrations. It was systematically studied under standard NACE condition and high pressure carbon dioxide field condition with variation in other key parameters (temperature, pressure and hydrogen sulfide concentration). The HIC and SSC were tested using a High Pressure and High Temperature (HPHT) Autoclave. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP). The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and non-sour services carbon steel. In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel.

Experimental and Analytical Investigation on the Effect of Heat Treatment Parameters on the Mechanical Properties of an API 5L X65 Steel

High Strength Low Alloy steels (HSLA) for oil and gas pipelines should display high mechanical strength, toughness, ductility and weldability. In this work we studied the influence of quenching and tempering temperature on the yield strength, ultimate tensile strength, percent elongation and hardness of API 5L steel pipes in order to optimize heat treatments to be performed after hot induction bending of the material. The thermal cycles involved soaking temperatures of 880, 920 and 960 °C, cooling water at 15, 23 and 31 °C and tempering at 530, 600 and 670 °C. From this, experimental design techniques were used to reduce the number of experiments. The results from contour maps suggest that soaking temperatures of 910 and 950 °C and tempering between 540 and 610 °C were the most suitable for treatment, regarding mechanical strength. The variation of the water temperature was not significant for the assumed cooling conditions. The prediction regression models of the mechanical properties from the variables involved in the heat treatments showed a good fit between the experimental and predicted results, with correlation coefficient between 0.89 and 0.94.

The study of corrosion behaviour api 5l steel in sea water using immersion test method

API 5L steel, a low carbon steel with a high alloy content, is often used as an underwater construction material or oil and gas pipeline. Banten has a wide sea area and has a long coastline where part of the coastline is used for petrochemical industries. There are three coast areas of Banten, namely Bayah Rangkasbitung, Anyer and Merak, that are used for petrochemical industries. Most of those industries use API 5L steel for underwater construction materials and pipes to channel seawater, chemical compounds, gas and oil. Whereas, seawater will greatly affect the lifetime of API 5L construction steel because it can cause corrosion. The purpose of this study is to analyze the corrosion characteristics of API 5L steel affected by the environment of seawater media and the temperature of seawater in accordance with its natural conditions. The samples of API 5L steel were immersed in seawater media with variation of immersion time of 5, 10, 15 Days and variation of immersion temperature of 20°C, 40°C, and 60°C. In this study, a series of tests were carried out, namely immersion test, weight loss test, and SEM test (Scanning Electron Microscopy). The highest corrosion rate on API 5L steel is 0.39 mmpy which belongs to Merak’s seawater media in the immersion time of 15 Days and the temperature of 60°C, while the lowest corrosion rate on the API 5L steel is 0.013 mmpy which belongs to Bayah’s seawater media with a time of immersion of 10 Days and a temperature of 20°C.