Steel Pipe Research Articles

Influence of the elevation effect of slope blasting on the vibration velocity of existing buried steel pipes.

Blasting vibration(BV) may cause the instability and damage to the surrounding structures and infrastructures, even leading to serious accident. As far as slope blasting is concerned, more and more attention has been paid to the elevation effect of BV of rock mass. However, scarce information is available on the influence of the elevation effect of slope blasting on the BV of surrounding structures, especially the existing buried pipes. As a consequence, the influence of the elevation effect of slope blasting on the BV of steel pipes was numerically investigated according to finite element model, which was verified against the experimental result. Moreover, the formula is presented to predict the peak vibration velocity (PVV) of steel pipes under slope blasting. It is found that PVV of the steel pipes has the elevation amplification effect in the terrain with positive or negative elevation difference. PVV of the pipes in the terrain with positive elevation difference is greater than that in the terrain with the same negative elevation difference. The elevation effect is more obvious under the condition of the positive elevation difference (2.1-5.1m). The modified Sadovsky's empirical formula is more suitable to predict PVV of the buried steel pipes during the slope blasting process.

Axial behaviour of steel pipelines buried in sand: effects of surface roughness and hardness

Surface roughness and coating hardness of underground pipelines are expected to play decisive roles in their axial pullout behaviour, which is an important aspect of pipeline design. Existing guidelines and previous studies underestimated or ignored these effects, resulting in potentially unsafe design. To address this problem, in the current study, nine large-scale physical modelling tests were conducted on pipes in dry and dense sand. Five steel pipes with varying normalised roughness (0·04–1·01) and coating hardness (32·6–59·0 HRA) were used and instrumented with a novel type of film-like piezoresistive sensors for measuring soil–pipe contact pressure. The measured pullout resistance of rough pipes is 2·70–2·85 times that of smooth pipes, significantly greater than the value specified in current design guidelines (i.e. 1·17 times). This substantial increase stems from an increase in interface friction coefficient (accounting for 72–79%) and a contact pressure increase induced by constrained dilation and soil arching (contributing the remaining 21–28%). Regarding coating hardness, a critical hardness was observed (around 35 HRA). Owing to equivalent roughness from particle embedding, pipes with hardness below this value exhibited similar behaviour to rough pipes. Finally, a new and simple method was proposed for calculating the pullout resistance with consideration of the effects of roughness and dilatancy.

Texture and surface morphology influence of A106 carbon steel pipe on mechanical properties and corrosion resistance after welding process

The surface morphology influenced the corrosion resistance, which depended on the welding process and its parameters. In this study, we investigated the relevance of the welding process that produces excellent mechanical properties and corrosion resistance, which gives the best working performance for carbon steel pipes that transfer refined oil products in an Iraq oil refinery. AISI 1020-A106 carbon steel pipes are welded using shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). Electrochemical corrosion tests were performed in 3.5% NaCl and immersion tests in heavy Naphtha at 50, 75, and 100 °C. The results show that retained austenite, ferrite, pearlite, and martensite phases are produced after the SMAW process. In contrast, ferrite, pearlite, and a small amount of martensite are produced after GTAW. The ultimate tensile strength of the SMAW samples was higher than those of the GTAW samples, but the GTAW samples had higher fracture elongation, and all samples had no cracks in the welding area during the bending test. The electrochemical and immersion corrosion rates of the samples welded with SMAW are higher than those welded with GTAW. The corrosion rate increases when the naphtha temperature increases and has a higher and unacceptable value at 100 °C.

Study of corrosion and failure mechanism of the galvanized steel pipes of meteorological tower serviced in the South China Sea

Corrosion issues of steel in the natural tropical marine atmospheric environment widely exist, and they can easily cause the failure of engineering equipment. However, the related studies are poor. Therefore, a deep analysis of the corrosion behavior and failure mechanism of steel materials in natural environments is urgent and important. In this work, the corrosion and failure mechanisms of galvanized steel pipes of a meteorological tower in the South China Sea were deeply studied. Results demonstrated that galvanized steel pipes at a low height happen a serious uniform and localized corrosion, while the bottom surface of each pipe facing the ground is severely corroded. The damage to the galvanized layer and the subsequent steel corrosion in high temperature and humidity conditions are mainly caused by bacteria and Cl−. Some bacteria with high corrosivity, such as Desulfovibrionales, Seminibacterium, Acinetobacter, Ralstonia, Proteobacteria Streptococcus, and Lactobacillus, are found beneath the rust layer, and they can significantly accelerate steel corrosion. The maximum localized corrosion rate is 0.20 mm/y.

A dual fracture mechanical approach for estimating notch stress intensity factor and T-stress using volumetric methods on API 5L pipe steel: Experimental study and numerical validation

This study focuses on the evaluation of the Notch Stress Intensity Factor (NSIF) as a key parameter for estimating the material's master failure curve in API 5L pipe steel. The research encompasses both experimental investigations and numerical validations to comprehensively assess the applicability of NSIF in predicting failure behavior. Through a series of controlled experiments, various notched specimens were subjected to different loading conditions, allowing the determination of NSIF values. Concurrently, a numerical framework was developed using finite element analysis to simulate the stress distribution near the notches. The experimental results were compared with the numerical simulations to validate the accuracy of the proposed approach. This research contributes to enhancing the understanding of how NSIF can serve as a reliable indicator of failure potential in industrial applications, particularly in the context of pipeline structures. The findings highlight the significance of NSIF-based predictions in ensuring the integrity and safety of materials under varying loading conditions.

Experimental investigation and numerical simulation of swaging process of tubes for oil country tubular goods

AbstractPremium integrated seamless pipes made from high strength low alloy steels are used to produce oil country tubular goods. Operational requirements of these pipes in petroleum industry lead to an adequate tube end connection with better mechanical strength and sealing properties. Therefore a cold swaging process or calibration of pipe end is necessary for the mechanical threading process of the tube. Applications of typical calibration mandrels result in heavy wear due to higher swaging loads and the optimal necessary geometry of end tube could not be achieved. In this study, a new mandrel geometry with a finished surface was developed to modify the pipe end profile and reduce the wear tool. The investigated pipe made from P110- pipe steel was plastically preformed using a cold swaging process. Experimental measurements of the pipe end geometry after swaging process resulted an increase of the inner tube diameter of approximately 4.9% and an outer tube diameter of 3.7% respectively. Furthermore, a rather constant tube wall thickness was also observed. An Abaqus plug-in was developed to characterize the swaging process of pipe ends. The influence of friction between tool and pipe surfaces on the final geometry of pipe ends and residual stresses in pipe ends due to preforming were numerically predicted. The new designed swaging process resulted a better final pipe end geometry and low tool wear during the preforming of pipe end. The presented plug-in in this work could be used for tool optimization and characterization of swaging process of pipes in oil and gas industries.

Biostability assessment of ultrapure water piping materials in the semiconductor industry and their susceptibility to Ralstonia growth

The pipes used for ultrapure water (UPW) distribution are constructed using high-quality materials to ensure purity. However, there remains a risk of contamination based on the pipe type. This study is the first to comprehensively evaluate the biological implications of various UPW pipe materials used in the semiconductor industry. The results showed that Polyvinylidene fluoride (PVDF) exhibited lower organic carbon leaching (0.08 mg/L) and a reduced biomass formation potential (BFP) (approximately 5 × 105 cells/cm2) compared to chlorinated polyvinyl chloride (CPVC) pipes. In particular, Ralstonia, an oligotrophic bacterium commonly found in UPW systems, formed a significant biofilm on pipe surfaces, notably in stainless steel (SUS) and CPVC pipes. Furthermore, particle contamination, a critical concern in semiconductor manufacturing, was investigated, focusing on potential contamination sources generated by pipe leaching and the presence of bacteria. The bacterial composition of the selected UPW was investigated, revealing Herbaspirillum, a nitrogen-fixing bacterium, as the dominant species, account for 66.15 %. Notably, the composition of the feedwater was different from that of the UPW. This study also highlights the limitations of culture-based methods, particularly in detecting bacteria under oligotrophic conditions, which are often unculturable. Flow cytometry (FCM) shows promise for the quick detection of bacterial contamination by providing total cell counts. Moreover, cytometric fingerprinting analysis revealed phenotypic differences between the communities. Nevertheless, further development of a simplified and widely applicable cell counting protocol is required for its effective integration into UPW production.

Corrosion measurement of thermally sprayed carbide coatings on stainless steel pipes

The petrochemical industries face a formidable challenge from corrosion, which leads to high maintenance costs and lost production. Traditional corrosion monitoring methods frequently fail to provide accurate and reliable results. As a result, these components must be replaced or repaired promptly to avoid increasing costs and limiting component life, which will reduce operation efficiency. Novel techniques with demands for high surface qualities in the future will be applied to develop alloys with better performance and more diverse applications. This study examines the corrosion resistance of cermet coatings, such as tungsten carbide (WC) and Chromium carbide (Cr3C2), in acidic solution by electrochemical impedance spectroscopy and electrochemical potentiodynamic polarisation. Additionally, utilizing optical microscopy techniques, the microstructural characteristics of coatings were assessed. According to the results of the Tafel polarisation test, Cr3C2 coating exhibited a lower rate of corrosion than other coatings. The Cr3C2 coated, WC coated, and uncoated samples reported corrosion rates of 0.924, 1.122, and 2.599 mmpy respectively. The corrosion resistance of Cr3C2 and WC coatings was increased by 64% and 53%, respectively, in comparison to uncoated specimens. This suggests that the coating maximizes economy, minimizes maintenance costs, extends the structure's lifespan, and reduces down the rate of corrosion.

Fabrication and Characterization of Graphene Oxide – Cadmium Sulphide Nanocomposite Coating for Corrosion Inhibition of Mild Steel Specimen

Abstract The oil and gas sector play a significant role in the Sultanate of Oman’s economic growth and contribute major revenue. Corrosion is a global concern and that strongly affects the industrial sectors. The corrosion problems in oil pipelines would be successfully resolved by means of novel control techniques. This research focused on the fabrication of Graphene oxide (GO) - Cadmium sulphide (CdS) nanocomposite for controlling corrosion in mild steel specimen. Graphene oxide was synthesized from Alovera extract by carbonization process. GO - CdS nanocomposite was prepared and deposited on a mild steel pipe by self-assembly technique. The coated material was used for stability studies at varying pH conditions and exposure period followed by corrosion studies. The testing methods adopted are Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Energy Dispersive X-Ray analysis (EDX), and Fourier Transform Infrared Spectroscopy (FTIR). Wet/Dry test and Atmosphere tests were conducted to examine the performance of coating material towards corrosion. The atomic force microscope (AFM) operated in non-contact mode was used to study surface topology of the coated specimen. From the outcome of the corrosion studies, it was established that the GO- CdS Nano composites thin film acted as an ecofriendly corrosion inhibitor to enhance the lifespan of the mild steel pipe. This novel research is aligned with the United Nations Sustainability Goals (UNSD - 9: Industry, Innovation and Infrastructure & UNSDG 12 – Responsible consumption and production) and Oman vision 2040. The results from the study validates that the GO - CdS thin films coated on mild steel pipe could be a viable solution to corrosion issues in oil pipelines owing to their good film stability, minimum film thickness, high durability, and ecofriendly approach.

Optimisation of Beam Member Loading

Introduction. The I-beams are deemed to have the highest load-bearing capacity. However, in practice, due to wide spreading and affordability of pipe-rolling products, the tubular beams are being used quite often. The load-bearing capacity of these beams should be compared under the condition of their equal mass per running meter. An I-beam according to the GOST R 57837-2017 with the mass of running meter equal to 194 kg and a pipe according to the GOST 33228-2015 with the mass of 194 kg/m have been compared. The load-bearing capacity of an I-beam was almost twice as high as that of a tubular beam. The data about the concrete filled steel tubular (CFST) beams, including the ones with the prestressed concrete core at the bottom, is also provided. In such beams, a steel pipe works as an external reinforcement — exo-reinforcement. The load-bearing capacity of the CFST beams is quite considerable taking into account their low cost and good processability. The present research aims at increasing the load-bearing capacity of the tubular beams, which will expand the range of the construction products.Materials and Methods. The geometric optimisation and mental experiment methods have been used. The idea of using the fluid filling material for a tubular beam is based on the well-known property of fluid — its almost complete incompressibility. The maximum volume of a geometric long body with the rectilinear generatrix of lateral surface (for a given lateral surface) is reached if its cross-section has the shape of a circle, which corresponds to a round pipe.Results. A tubular beam with the fluid filling material (a hydraulic beam) is a round pipe blanked off at both ends, completely filled with fluid (without air pockets). When a hydraulic beam is loaded, its lateral surface tends to deform. Consequently, the internal volume of the pipe tends to decrease. However, since fluid is incompressible, its volume doesn’t decrease, which, in turn, prevents the pipe from deformation.Discussion and Conclusion. In a hydraulic beam, due to fluid, the entire load is distributed relatively evenly over the whole internal surface of a beam. The load-bearing capacity of a hydraulic beam has been estimated, which is five times higher than that of an I-beam and ten times higher than that of a tubular beam.

PSO-BP model for assessing frost resistance in containment concrete with varying pipe diameters

The safety of containment concrete is of utmost importance for nuclear power plants. The presence of pipe openings in the containment concrete structure introduces weakened areas, which adversely impact the mechanical properties and durability of the concrete. However, little research has been done on the durability of containment concrete with embedded steel pipe (CCESP), and no studies are found on its frost resistance under single-side freezing and thawing conditions. In this paper, using single-side salt freeze-thaw experiment to simulate the practical situation of coastal containment concrete, the effect of different steel pipe diameters (d) on the frost resistance of containment concrete was investigated. Based on the experimental results and using backpropagation neural networks optimized by a particle swarm algorithm (PSO-BP), a model was established to predict the frost resistance of CCESP for varying values of d. The research results showed that wall effects and stress concentrations created an interface zone between the steel pipes and the concrete, leading to a decline of compressive strength. Freeze-thaw cycles had only a slight impact on the relative dynamic elastic modulus (E) of CCESP, while the exfoliation mass per unit area (M) of the concrete specimens increased linearly with d. It indicates that pipe opening adversely impacts the frost resistance of the concrete, and that M can be used to evaluate the frost resistance of CCESP. This study addresses the research gap in the frost resistance of containment concrete with steel pipe openings, and the proposed PSO-BP model can accurately predict the frost resistance of containment concrete with varying pipe diameters under different freeze-thaw cycles.

Effective Press Folding Line Process as Producing Smart Intersection in Square Steel Pipe Structures by Using Crushed Cross Section Compactly

As a cross section of square steel pipe is crushed, the upper plate and the lower plate deform inward, and the side plates deform outward from the original square cross section shape. When the press folding line process as deformation induction is applied, the upper plate and the lower plate keep flat, and the side plates are compactly folded inward. This deformation pattern is safe without causing any harm to the surrounding area, and makes it possible to improve impact energy absorption performance by folding side plates as overlapping. Moreover, square steel pipe structures include places as pipes intersect and places to avoid interference with other parts (piping, wiring, fork claws, etc.). In such cases, the current method is to create an opening by cutting off. At that time, the structural strength will decrease, so reinforcing materials are often installed as a countermeasure. On the other hand, if the opening is processed by laterally impact crushing using the press folding line process proposed in this paper, a crushed part will remain, suppressing the decrease in structural strength, and this can be handled without adding reinforcing material to be a smart intersection. This paper shows the findings based on experimental data, FEM (Finite Element Method) results on processing conditions for inward deforming side plates of square steel pipes and evaluation of impact energy absorption performance in laterally impact crushing.

Corrosion-mechanical destruction of bainite structures in oilfield environments

The main direction in solving the problem of increasing the reliability of field equipment, is the creation of new steels with higher resistance to corrosion-mechanical destruction. Currently, to produce oil and gas pipeline systems, low-carbon, low-alloy steels are used, in which lath carbide-free bainite is formed when quenched in water. Such a structure provides a combination of high strength and resistance to brittle fracture. However, issues of increasing corrosion resistance are still open. The purpose of this work is to identify the structural condition of low-carbon, low-alloy, pipe steels, providing a combination of high mechanical properties with increased corrosion resistance in oilfield environments. The studies were carried out on the latest generation 08KhFA, 08KhFMA and 05KhGB steels, most popular when manufacturing oil and gas pipelines. Samples for the study were cut from the pipes and quenched from the austenite region in water, which formed the structure of lath carbide-free bainite. The quenched samples were tempered at temperatures of 200, 300, 400, 500, 600, and 700°C. To identify the relationship between the morphology of bainite structures and their properties, the samples after quenching and tempering at each temperature, were subjected to metallographic analysis, X-ray diffraction analysis, mechanical tests, and corrosion resistance tests. The work shows the sequence of structure transformation, temperature ranges of phase and structural transformations, changes in mechanical properties, and corrosion resistance that occur during tempering of lath carbide-free low-carbon bainite. It is shown that tempering of lath carbide-free bainite (08KhFA, 08KhMFA and 05KhGB steels) does not affect the rate of carbon dioxide corrosion. It has been found that medium tempering forms the structural condition of carbide-free low-carbon lath bainite providing a combination of high mechanical properties and high corrosion resistance in oil field environments. For each of the steels under study, the authors give recommended heat treatment modes.

Structural Rehabilitation of API Steel Pipes Using GFRP Under Dynamic Condition

Structural Rehabilitation of API Steel Pipes Using GFRP Under Dynamic Condition

Studying the Microstructural Evolution in a Hot-Rolled Thick Gauge Microalloyed Line Pipe Steel

Studying the Microstructural Evolution in a Hot-Rolled Thick Gauge Microalloyed Line Pipe Steel

A novel test set up to study three-dimensional electrokinetic dewatering of dredged soil

The dredged soil obtained from maintenance activities of water bodies has emerged as a potential alternate fill material for infrastructure development. However, dredged soil requires stabilization due to high initial water content, low shear strength and high compressibility. Among several methods, stabilization of dredged soil by using electrokinetics is one of the effective ground improvement techniques that uses electric field to dewater and strengthen the soil. In this context, a series of experiments were conducted on dredged soil by using a combination of electrokinetic treatment with and without 6 kPa seating pressure (viz., low surcharge). A customized and patented electrokinetic dewatering (EKD) test set up was used for the three-dimensional electrokinetic treatment of soil. The potential difference (in the range of 6 V–48 V) within the soil was achieved by inserting stainless steel pipes of 21.4 mm outer diameter, 1.2 mm thickness, and 170 mm length. Two control tests (with and without seating pressure of 6 kPa) also were performed to understand the effectiveness of EKD. From the study, up to 1057% and 427% increase in dewatering was noted in EKD tests due to application of 24 V (optimum voltage noted in EKD tests) as compared to control tests, without and with seating pressure, respectively. Further, seating pressure with EKD resulted in effective control of crack formation in the dredged soil and uniform improvement in shear strength along the depth (up to 95 kPa). The combination of low surcharge with EKD, adopted in the study, is also expected to yield lower differential settlement, and hence better performance of geotechnical structures built on improved dredged soil. The novel 3-dimensional patented EKD test setup with Arduino-programmed automatic water pumping enables collecting and accurately measuring dewatered effluent volume, performing cone penetration tests on undisturbed soil, and collecting soil samples for determination of water content/physiochemical properties from different locations. Overall, the developed EKD setup can be utilized for evaluating the effectiveness and adopting real-time progress management for EKD or other ground improvement methods, and remediation of sludge, mine tailings, dredged sediments, and contaminated soils.

Water Separation and Formation of Cells with Differential Aeration as Factors Controlling Corrosion of Steel Pipelines in a Crude Oil Storage Facility

The mechanism causing the dramatic intensification of the corrosion deterioration of carbon steel pipes in a crude oil storage facility has been investigated. This study considers a number of factors affecting corrosion in crude oil, such as the water content, the corrosivity of the aqueous phase, the kinetics of water–oil separation, the effect of dissolved oxygen, the effect of the crude oil quality, the degree of stagnancy inside of the pipes, the possible contribution of microbially induced corrosion (MIC) and the presence of deposits. The key root of the corrosion intensification was the separation of the water phase, supported by stagnancy, which eventually led to the formation of stable shallow pits surrounded by cathodic areas.

Study on shear performance of BMSCC prefabricated shell and square steel tube composite permanent formwork beam

A novel type of permanent formwork (PF) concrete beam has been proposed with the aim of reducing carbon footprint, conserving energy, and enhancing construction efficiency. Specifically, the U-shaped PF is constructed using basic magnesium sulfate cement mortar, and square steel pipes with holes are utilized in place of traditional vertical and horizontal reinforcements. During on-site construction, the composite beam can be easily completed by pouring ordinary concrete into the PF. Shear failure tests were conducted on two PF beams and a reinforced concrete (RC) contrast beam with varying strip spacing. It was observed that the remaining rectangular steel strips, resulting from opening holes on both sides of the square steel pipe, acted as shear stirrups. The results indicate that the PF beam demonstrates typical shear and compression failure, and the precast shell is securely bonded to the core concrete without any peeling phenomenon. When comparing to an equivalent RC beam with the same transverse steel yield strength and dosage, the cracking load of the inclined section is increased by 28.3 % and the ultimate load is increased by 21.4 %. Compared to RC beams, PF beams exhibit an increased number of cracks but reduced width. And The ductility of PF beams were improved. Decreasing the distance between steel strips on both sides of the PF beam results in an 10.3 % increase in cracking load and a 9.4 % increase in ultimate load. By introducing the concrete constraint coefficient and the steel tube web resistance coefficient, the formula for calculating the shear capacity of the PF beam was established.

Comparative Study for Corrosion Resistance of Ferrous and Non-ferrous Pipes Immersed in Magnetized Water

This study aims to investigate the corrosion resistance of galvanized steel (GS) and AZ31 pipe materials immersed in a magnetized water treatment (MWT) applied river water source. The potentiodynamic corrosion test results showed that a better corrosion rate is obtained by the AZ31(corr.rate: 0.0442 mm/y) specimen than GS (corr.rate: 0.0764 mm/y) due to the passivation efficiency resulting from the calcite and MgO particles on the surface.

Experimental studies of bearing capacity of pipe steel of sewage systems

The results of experimental studies on the kinetics of crack growth, its relationship with the parameters of crack resistance and long-term strength of pipe steels of different service life and their structural and phase composition are presented. It was found that the value of the critical stress SK for all test steels increases with the increase in the service life, and the impact viscosity decreases, which indicates the structural embrittlement of the pipe steels associated with their sudden flooding. It is shown that the new 06G2BA steel, which is economically modified with a carbide-forming element (vanadium) and has a fine-grained structure and a low content of harmful impurities (sulfur, phosphorus), has the highest visco-plastic properties and resistance to brittle fracture. The microstrain of the α-Fe crystal lattice, as well as the quantitative decay of cementite and the redistribution of carbon between ferrite and pearlite, were evaluated by X-ray structural methods. 06G2BA steel is recommended for use in the construction of pipelines and, for example, bridge structures, which are constantly under cyclic loads with simultaneous contact with a corrosive-aggressive environment. The influence of the service life of water pipes on the hydrogen content and microcracks in pipe steels was determined. A diagram of the relationship between long-term and static strength depending on the hydrogen content in steels is recommended, which can be used by designers to rationally choose the type of steels with high crack resistance in aggressive technological environments. In order to extend the service life of pipe structures, it is necessary to use economically modified steels.