Steel Pipe Research Articles

Intelligent identification method for pipeline ultrasonic internal inspection

ABSTRACT In pipeline ultrasonic testing, the accurate identification of defect types is a prerequisite for quantifying defect sizes. To this end, this paper proposes a defect identification algorithm based on the combination of Wavelet Packet Transform (WPT), Distance Evaluation Technique (DET) and GA-SVM to precisely identify defect boundaries. First, the ultrasonic echo signals are processed using WPT to more accurately extract defect information. Then, DET is employed to eliminate redundant feature parameters, which are sorted by sensitivity to determine the input feature parameters for the GA-SVM. On this basis, a self-developed ultrasonic testing experimental system is used to collect ultrasonic echo signals from Q235 steel pipes with cylindrical, spherical, and conical defects at different spatial orientations of the probe and the pipe. After processing and identifying the signals, it was found that the proposed algorithm achieves an average identification accuracy of 99% for different types of defects, thereby realising automatic identification of pipeline defects. The results provide new ideas and methods for the intelligent identification of volumetric defect types in pipeline ultrasonic internal testing and promote the development of industrial-grade ultrasonic internal detectors.

Experimental Study on Axial Compressive Performance of Recycled Steel Fiber Reinforced Concrete Short Columns with Steel Pipes

Experimental Study on Axial Compressive Performance of Recycled Steel Fiber Reinforced Concrete Short Columns with Steel Pipes

Effectiveness of Dry Cleaning Treatments for Removing Milk Chocolate from Valve/Pipe Assemblies and Pilot-scale Chocolate Processing Equipment

Dark chocolate produced on equipment used to manufacture milk chocolate can contain milk due to cross-contact. This study evaluated the use of dry cleaning methods for removing milk chocolate residue from a butterfly or ball valve attached to a stainless steel pipe and from pilot-scale equipment used in chocolate manufacture. Milk-free dark chocolate (40 °C) was pumped through a milk chocolate-contaminated valve/pipe assembly after no cleaning, use of a pig purging treatment, or a 40 °C cocoa butter flush. Dark chocolate samples were collected at 7-sec intervals. Treatments investigated for the removal of residual milk chocolate from a conche and a ball mill included no cleaning, a 40 °C cocoa butter rinse, and wet cleaning. After cleaning, three batches of dark chocolate (40 °C) were processed in the ball mill and conche, and each batch was collected. Milk chocolate was processed on a 3-roll refiner, followed by push-through with dark chocolate (∼9 kg) with 0.3 kg samples collected at 5-min intervals. Dark chocolate samples were analyzed for milk concentrations by ELISA. Trials and analyses were completed in triplicate. Dark chocolate push-through alone resulted in milk concentrations ≥4,500 µg/g in samples obtained from the contaminated valve/pipe combinations within the first few seconds of collection, and ≥16.2 kg of dark chocolate was needed to obtain milk concentrations below the ELISA LOQ (2.5 µg/g). A pig purging treatment of the ball valve/pipe assembly resulted in milk concentrations below the ELISA LOQ. A cocoa butter flush of the butterfly valve/pipe decreased initial milk concentrations, but milk was detected until ≥18.7 kg dark chocolate purge. Milk concentrations in first batches of dark chocolate processed in a ball mill and conche without cleaning were ≥17,000 µg/g while the use of a cocoa butter rinse reduced milk levels in dark chocolate by ≥89%. Some dry cleaning treatments were effective at reducing levels of milk in dark chocolate due to cross-contact.

An interpretable machine learning-based pitting corrosion depth prediction model for steel drinking water pipelines

Steel pipes are a crucial element of the water supply system and are necessary for safely delivering large quantities of water from purification plants to consumers. Corrosion is a significant factor that deteriorates the interior and exterior of the steel pipes. Although the effectiveness of machine learning has been demonstrated in various fields, machine learning has rarely been used to identify corrosion mechanisms in buried steel pipes. A hybrid machine-learning–based corrosion depth prediction model was developed by integrating a corrosion depth trend prediction model based only on elapsed years with machine-learning algorithms. Shapley additive explanation (SHAP) was used to analyze the hybrid machine-learning–based corrosion depth prediction models, revealing corrosion mechanisms and explaining the interactions among influencing factors through global and local interpretations. The SHAP local interpretation showed that the hybrid machine-learning–based corrosion depth prediction models can effectively capture the interrelationship between soil and water corrosiveness.

Research on Acid Aging and Damage Pattern Recognition of Glass Fiber-Reinforced Plastic Oil and Gas Gathering Pipelines Based on Acoustic Emission.

Pipelines extend thousands of kilometers to transport and distribute oil and gas. Given the challenges often faced with corrosion, fatigue, and other issues in steel pipes, the demand for glass fiber-reinforced plastic (GFRP) pipes is increasing in oil and gas gathering and transmission systems. However, the medium that is transported through these pipelines contains multiple acid gases such as CO2 and H2S, as well as ions including Cl-, Ca2+, Mg2+, SO42-, CO32-, and HCO3-. These substances can cause a series of problems, such as aging, debonding, delamination, and fracture. In this study, a series of aging damage experiments were conducted on V-shaped defect GFRP pipes with depths of 2 mm and 5 mm. The aging and failure of GFRP were studied under the combined effects of external force and acidic solution using acoustic emission (AE) techniques. It was found that the acidic aging solution promoted matrix damage, fiber/matrix desorption, and delamination damage in GFRP pipes over a short period. However, the overall aging effect was relatively weak. Based on the experimental data, the SSA-LSSVM algorithm was proposed and applied to the damage pattern recognition of GFRP. An average recognition rate of up to 90% was achieved, indicating that this method is highly suitable for analyzing AE signals related to GFRP damage.

Contact electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen transportation

The issue of electrostatic safety in liquid hydrogen systems has garnered increasing attention, especially concerning the potential threat of electrostatic explosions due to the collision-electrification phenomenon of solid oxygen particles formed after air leakage in liquid hydrogen pipelines. To delve into the contact electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen transportation, a mathematical model based on the computational fluid dynamics-discrete element method (CFD-DEM) two-phase flow dynamics has been developed. This model integrates the Hertz contact theory for describing particle collision processes and the condenser model for describing particle collision-electrification. The reliability of this model has been validated in existing literature through its ability to capture the flow characteristics of two-phase flow and the electrification characteristics of particle groups. Using density functional theory to compute the solid oxygen work function and considering the low-temperature properties of liquid hydrogen, a series of numerical studies on the flow sedimentation and electrification characteristics of solid oxygen particle-laden flows in liquid hydrogen pipelines have been conducted. The results indicate that particles carry negative charges after colliding with stainless steel pipe walls, with single charge exchange magnitudes of approximately 10−12C for particle-wall continuous collision processes and 10−14C for particle-particle collision processes, resulting in particle charge-to-mass ratios on the order of tens of μC/kg at the outlet interface. The impact of electrostatic forces on particle motion is significant and cannot be overlooked. Furthermore, the effects of velocity, particle diameter, and pipe diameter on particle charge characteristics have been thoroughly analyzed. At low flow velocities, severe particle settlement occurs, leading to increased collision frequency between particles and walls and significant charge accumulation. Increasing flow velocity can mitigate particle settlement and reduce charge levels. Changes in particle and pipe diameters have a minor impact on particle settlement but can increase single charge amounts with larger particle diameters and intensify particle charging with reduced pipe diameters due to shortened radial travel distances, leading to increased collision frequency. Our study meticulously illustrates the charge characteristics of individual particles and particle groups, providing a theoretical basis for assessing the electrostatic safety of liquid hydrogen transportation systems under extreme conditions.

Microstructural, mechanical and nondestructive characterization of X60 grade steel pipes welded by different processes

Abstract In this paper, the welding quality of API 5L X60 steel pipes was investigated after the application of three different welding scenarios by applying submerged arc welding (SMAW), tungsten inert gas (TIG) and hybrid (TIG + SMAW) welding methods with an average heat input of ca. 1 kJ mm−1 for all passes. For this purpose, the ultrasonic and radiographic tests were done to detect possible discontinuities such as crack and porosity in the welding zones. In addition, the macro and microstructures of weld zones were made to examine different zones in terms of weld quality and phases. Moreover, the hardness, impact toughness and tensile tests were carried out to determine the mechanical properties of the weldments. The tensile strength of the pipe weldments was recorded to be ∼603, 610 and 625 MPa after the welding of pipes by SMAW, TIG + SMAW and TIG welding, respectively. In addition, the impact toughness of the welds was obtained to be 48, 76 and 66 J, for these welding methods, successively. According to the experimental findings, all three welding plans were successfully applied to the steel pipes and found to be suitable regarding the relevant international standards.

Assessment of piles’ resistance driven sequentially in fine-grained soils using pile load tests

This paper presents a field pile load test program conducted on four 0.36 m closed-end steel pipe (CEP) piles with lengths ranging between 11 to 13 m installed in fine-grained soils. Subsurface investigations with standard penetration tests (SPT) and cone penetration tests (CPT) with pore pressure measurements were performed at the site. Three pushed-in piezometers at incremental offsets from the piles were also installed to monitor pore water pressure changes during and after the installation of piles. Several dynamic load tests (DLT) were performed at different times to observe the change in pile resistance. A static load test (SLT) was also performed on one of the piles. Some load test results showed an unexpected decrease in the resistances of some piles with time. The study showed that construction activities, e.g. installation of other piles, disturbs the soil and groundwater conditions which can significantly affect the pile resistance measured during load tests. This investigation revealed that pile driving and restrikes should be scheduled such that the effect of construction activities on load tests results will be avoided or minimized.

Параметры, влияющие на стоимость продукции металлургических и трубопрокатных производств в различных регионах РФ

The article considers the market of oil products, the prices of which directly affect the cost of production of the strategically important pipe rolling industry, by years and regions. The geography of metallurgical enterprises location on the territory of the Russian Federation and regional zones are analyzed. Generalized indicators of the Russian steel pipe market are structured by key indicators and federal districts depending on average consumer energy prices in the domestic market. The geographical factor that most strongly influences the final cost of power supply to pipe rolling enterprises-consumers in price zones was identified.

A phase field method for predicting hydrogen-induced cracking on pipelines

An accurate determination of the threshold conditions to initiate cracks on aged hydrogen pipelines is paramount for ensuring energy transport safety. In this work, a finite element-based phase field method was developed to assess the crack initiation on dented pipelines while considering the hydrogen (H) impact. Theoretical and multi-physics numerical formulas were derived for prediction of the elastic-plastic fracture behavior of H-contained steel. A critical phase field parameter, ϕ=0.69, is defined for predicting crack initiation at the dent on pipelines. The presence of H within the steel decreases the threshold dent depth for initiating H-induced cracks. When the initial H concentration increases from 0 to 0.5 wppm, the maximum dent depth for crack initiation reduces from 17.5 mm to 10.7 mm. The maximum dent depth required for crack initiation reduces from 17.5 mm to 7.8 mm when an internal pressure of 8 MPa is applied on the steel pipe. The site with the maximum phase field parameter changes during indentation, implying that the location initiating cracks depends on the dent dimension. The existing criteria in ASME B31.12 standard are not applicable for predicting H-induced crack initiation on dented pipelines. This study proposes a new method to predict hydrogen-induced cracking on aged pipelines when transporting hydrogen.

Effects of Perforations on Internal Cathodic Protection and Recruitment of Marine Organisms to Steel Pipes

Effects of Perforations on Internal Cathodic Protection and Recruitment of Marine Organisms to Steel Pipes

Experimental Study of a Temperature Field in a Shut-in Well in Relation to Determining Behind-the-Casing Flow Using Active Thermometry

Abstract —This paper presents results of experimental studies of a thermal field in the barrel of a shut-in (no fluid movement in the casing) well in relation to determining a behind-the-casing upward flow using the method of active thermometry. The studies are carried out using the physical model of a well that is a vertically located steel pipe with a system of externally attached copper tubes simulating a behind-the-casing flow. The pipe contains a local heating section, above which a temperature probe is located to record thermal disturbance from the heating section. The effect of free convection in a fluid on the temperature field in the pipe during and after heating is described. It is revealed that there are high-frequency temperature oscillations on sensors that record the temperature of the inner surface (wall) of the pipe and fluid above the heating area, whose value reaches higher than 2 °C and decreases when the distance to the heating region becomes longer. There is an empirical relationship that relates the time of arrival of the temperature disturbance front associated with free convection and the distance to the pipe heating region. Azimuthal temperature distribution curves on the inner wall of the pipe above the heating section are constructed in the absence and presence of a behind-the-casing flow. Qualitative criteria have been obtained indicating the presence of an azimuthally localized behind-the-casing flow (sector flow) of fluid based on the azimuthal temperature distribution analysis.

A Limited Evaluation of the Applicability of NACE MR0175/ISO 15156 H2S Limits to Supercritical CO2 Pipelines

In an earlier paper one of the authors raised the question of whether the hydrogen sulfide (H2S) partial pressure threshold of 0.05 psia (0.3 kPa) for cracking of steels from sulfide stress cracking is pertinent to dense phase carbon dioxide (CO2) systems in which there is no free gas phase. This paper presents a limited test of the pertinence of this threshold value in Supercritical CO2. Autoclave tests of four-point bend beam specimens of API 5L Grade X80 line pipe steel at 0.05 psia (0.3 kPa) and 0.20 psia (1.38 kPa) H2S were performed and the samples were examined after testing for cracking. In addition, the test conditions were modeled with the OLI Studio software to determine the H2S fugacities and H2S concentrations in the brine phase. No cracking was found after 30 d of exposure.

Enhancing ASTM B424 UNS N08825 Long Seam Weld Liner Material with Annealing Quenching Techniques in the Cladding Process on the Surface of Steel Pipes

The use of cladding methods in manufacturing corrosion-resistant pipes is crucial for industries such as oil and gas, chemical plants, and pressure vessel manufacturing. This study focuses on ASTM B424 UNS N08825, a corrosion-resistant alloy (CRA) to be used as the surface layer for steel pipes. The cladding method involves forming CRA sheets into longitudinal pipes, followed by welding the joints, annealing, and rapid cooling before high process expansion to surface layer the steel pipes. At a temperature of 930-990°C, the annealing process aims to reduce stress and improve material properties, followed by rapid cooling to stabilize the microstructure. Various tests were conducted on the CRA liner pipes with or without annealing and quenching, including tensile testing, hardness testing, chemical composition analysis, and microstructure examination. The results showed that the material's ultimate tensile strength and hardness significantly increased after the treatment, with better uniformity in the microstructure. This study concludes that annealing and rapid cooling enhance the mechanical properties and stability of ASTM B424 UNS N08825, allowing the cladding process on steel pipe surfaces to be performed flawlessly and making it suitable for high-performance applications in corrosive environments.

Low-cycle fatigue behavior and microstructure evolution of ODS steel pipes at high temperatures

Oxide-dispersion-strengthened (ODS) steels are candidate materials for application in advanced nuclear reactors. In this study, the low-cycle fatigue performances of 13Cr-ODS ferritic steel pipes were investigated at 600, 700, and 800 °C. Cyclic softening was observed at high strain amplitudes with an increase in the number of fatigue cycles. However, cyclic hardening appeared first, and then cyclic softening occurred at a low strain amplitude with the increase in the number of fatigue cycles. By comparing the cyclic stress–strain curves and the monotonic stress–strain curves, it was found that cyclic softening occurred regardless of the strain amplitude. The Coffin–Manson and Basquin equations were used to predict the fatigue of the pipes. Microstructure analysis indicated that cyclic softening was induced by the dynamic recovery and recrystallization, which reduced the number of low-angle grain boundaries in the deformed grains by promoting dislocation annihilation and reorganization. A complex multi-layer core–shell structure with a large size (∼500 nm) was observed.

Experimental investigation on mechanical properties of fiber recycled concrete filled-square steel tube columns under pure flexural based on acoustic emission technique

Currently, global countries are actively focusing on carbon emission reduction. Utilizing recycled aggregate concrete (RAC) is expected to realize global carbon neutrality objectives. However, due to its inherent mechanical limitations, its application in structural contexts is restricted. This study aimed to enhance the mechanical attributes of RAC and expand its utility beyond low-strength applications. By employing recycled aggregates, steel fibers, and ordinary Portland cement, a novel eco-friendly composite filler was developed for steel- tube filling. A comprehensive study on 16 concrete mix ratios and 23 steel-tube recycled concrete columns was conducted. The parameters included the recycled aggregate volume, steel fiber content, and steel pipe thickness. The results revealed that reasonable mix design enabled RAC to exhibit flexural performance similar to that of conventional steel-tube concrete. Moreover, while increasing the recycled aggregate content deteriorated the overall mechanical properties, incorporating steel fibers extended the elastic stage and enhanced the flexural characteristics. Optimal results were achieved with 1.2 % steel fiber addition and 75 % recycled aggregate. The comparison between the derived equation and the experimental data demonstrated a high level of agreement, confirming the accuracy of the equation. Furthermore, acoustic emission technology was employed in this experiment to monitor the failure progression of steel tube recycled concrete columns subjected to a pure bending load. The findings revealed a triphasic failure process: elastic, elastic-plastic, and strengthening stages. The analysis demonstrated a consistent correlation between acoustic emission parameters and waveform characteristics with the failure process of the specimen. Empirical evidence demonstrated the efficacy of acoustic emission technology in effectively monitoring the damage severity and failure chronology in recycled concrete steel pipe columns during bending.

Implementation of the Gravity Location Models Method in Determining Regional Warehouse Locations to Minimize Goods Transport Costs at PT

Supply Chain is a network of companies that work together to create and deliver a product to the end user. PT X is a company engaged in manufacturing whose products are steel pipes, not only steel pipes are produced. Supply chain management at PT X is considered inefficient because it has to supply four warehouses or depots at once, this can cost a lot of shipping costs in the PT X Supply Chain process. Therefore, supply chain management needs to be carried out using the Gravity Location Model method which aims to minimize the costs of transporting goods at PT X. The aim of this research is to determine the variables needed to determine the location point of PT X regional warehouse using the Gravity Location Model method and to determine the regional warehouse location and optimal shipping costs using the Gravity Location Model method at PT X. From the results of research that has been carried out, the variables used to determine the location points for PT X regional warehouse construction include X and Y, Xn and Yn, dn, Cn, Dn, and TC as well as calculating cost minimization through a comparison of 20 iterations, it was found that the minimum cost was in the 11th iteration, namely IDR 386.955,50. with coordinates X = -4.13 and Y = 115,18.

CFD Modelling of Swirling Mechanism to Reduce Erosion of Pipe Bend in Pneumatic Conveying System

Dry powders mixed with air transportation had bend erosion issues. CFD analysis by Shear-Stress Transport (SST) k-ɯ Model within Ansys was used to conduct a comprehensive numerical analysis of particle erosion within a 90° mild steel pipe bend in Pneumatic Conveying System. Part of the conveying pipe rotation achieved with the external motor swirling device was used to create swirling of particle before bend. Different-sized sand particles at different rpm were tested with and without a swirling device. Reduction in erosion rate of pipe bend carries significant implications, notably an extension of the system's operational lifespan. Reduction in erosion rate reports an impressive increase of 50% bend lifespan at higher RPM levels of the swirling device. The results underscore the effectiveness of this device in mitigating erosion, with significant implications for enhancing the longevity and reliability of bend life in piping systems of Pneumatic Conveying applications.

Damage analysis in welded steel pipe elbow under strong cyclic loading

According to cyclic loading modes, highly pressurized tubular elements, such as those in elbows, differ from other straight tubular structures in their modes of stress and damage. This work aims to perform a numerical prediction of a tubular structure. It consists of an X52 steel elbow welded to X65 grade ends by straight tubular sections. This pressurized structure is subjected to strong cyclic loading in bending moment applied until damage occurs. The bending moment is combined with different orientations between the closing or opening moment and the out-of-plane moment, presenting a possible but rarely analyzed situation. This cyclic loading mode is taken as an evaluative parameter in its various amplitudes, orientations, and patterns. The cyclic hardening of the elbow and straight tubular sections, including those of the welded joints, are all formulated by the combined isotropic and kinematic model introduced in the ABAQUS calculation code with parameters calibrated according to the Voce model and experimental results, using plasticity by the Von Mises equivalent stress flow theory. The appropriate XFEM (Extended Finite Element Method) technique is used in conjunction with the hardening model to overcome numerical calculation difficulties and predict damage in traction laws, separation by crack initiation and propagation. The results, in the form of hysteresis curves in cyclic bending moment and angular displacement, have shown a strong dependency that conditions the structure’s response as well as the level of its damage.

Hydrodynamic performance of a submersible net cage integrated with an offshore platform

The integrated development of offshore platform and net cage is a significant concern in ocean engineering. To optimize cost-effectiveness and maximize the utilization of limited ocean space resources, a composite structure is proposed, which integrates a submersible net cage onto the steel pipe piles of offshore platform. Based on the OpenFOAM software package, a numerical model is developed to assess the hydrodynamic performance of this composite structure. In this model, the net cage is simplified as a closed box structure comprising six planar nets, with each planar net further represented as a porous structure based on equivalent resistance. The model is validated by comparing the predicted results with the relevant experimental and numerical data. Subsequently, the model is employed to comprehensively investigate the hydrodynamic performance of the submersible net cage integrated with an offshore platform. Velocity variations inside and outside the net cage are analyzed under various wave-current conditions. Additionally, the forces exerted on the steel pipe piles by the net cage at different submerged depths are also examined.