Composite Steel Pipe Research Articles

Analytical approach for lateral dynamic responses of offshore wind turbines supported by cement-soil composite steel pipe pile embedded in gassy marine sediment layer

This study aims to clarify and gain an insight into the lateral dynamic response of offshore wind turbines (OWTs) supported by cement-soil composite steel (CCS) pipe pile embedded in gassy marine sediment layer by developing an analytical approach. In the proposed approach, the CCS pipe pile-supported OWT system is divided into three parts including the tower part, the seawater-immersed steel pipe pile part, and the embedded CCS pipe pile part. The lateral dynamic behaviours of the CCS pipe pile-supported OWT system have been determined and then validated by solving the analytical solution of lateral displacement for the above three parts. Numerical discussions are finally conducted to analysis the influence of some physical parameters on the lateral displacement and the first-order natural frequency of the CCS pipe pile-supported OWT system. The main findings can be summarized as: (i) the offshore deep cement-soil mixing (ODCM) pile is an effective reinforcement method to reduce the lateral vibration of conventional steel pipe pile-supported OWTs; (ii) the increase in tower height and seawater layer thickness will have a serious negative impact on the lateral dynamic response of CCS pipe pile-supported OWTs; (iii) the increase in gas saturation of gassy marine soil will lead to a negative influence on the maximum lateral displacement of CCS pipe pile-supported OWTs.

Towards the Development of Novel Hybrid Composite Steel Pipes: Electrochemical Evaluation of Fiber-Reinforced Polymer Layered Steel against Corrosion.

Corrosion remains one of the major and most costly challenges faced by the steel industry. Various fiber-reinforced polymer coating systems have been proposed to protect metallic piping distribution networks against corrosion. Despite increasing interest among scientific and industrial communities, there is only limited predictive capability for selecting the optimum composite system for a given corrosive condition. In this study, we present a comprehensive evaluation of the electrochemical behavior of two different fiber-reinforced polymer composite systems against the corrosion of carbon steel pipes under a wide range of acidic and corrosive solutions. The composites were made of glass and Kevlar fibers with an epoxy resin matrix and were subjected to corrosive solutions of 0.5 M NaCl, 0.5 M HCl, and 0.5 M H2SO4. The kinetics of the corrosion reactions were evaluated using potentiodynamic polarization (PDP) tests. In addition, electrochemical impedance spectroscopy (EIS) tests were carried out at open circuit potentials (OCPs). It was demonstrated that the glass fiber-reinforced polymer coating system offered the best protection against corrosion, with a high stability against deterioration when compared with epoxy and Kevlar fiber-reinforced polymer coating systems. Scanning electron microscopy images revealed cracks and deteriorated embedded fibers due to acid attack, sustained/assisted by the diffusion of the corrosion species.

Carbon and energy footprint of nonmetallic composite pipes in onshore oil and gas flowlines

A Life Cycle Assessment (LCA) analysis was conducted to compare the carbon and energy footprint of several non-metallic composite pipes and carbon steel (CS) pipes used in onshore sour oil and gas (O&G) production flowlines, based on a specific deployment case (cradle-to-gate scenario). This work provides a systematic approach to assessing the carbon and energy footprint of fiber reinforced thermoplastic/thermoset pipes used in the O&G industry, while also accounting for the end-of-life recycling at the material phase, through the use of the recycled-content allocation method. The impact of corrosion allowance (CA), commonly used at design phase of CS pipes, is explicitly included and discussed. From the raw material extraction to the installation phase, all non-metallic pipe technologies assessed in this study were found to have a lower carbon and energy footprint than CS pipes. The reduction in CO2 emissions can reach up to 60% while the energy footprint can be reduced by up to 50%. The material phase, particularly the composite layer for non-metallic pipes, was found to be the main contributor to the product footprint for all pipe technologies and any optimization in this phase could translate into a significant reduction in the overall CO2 footprint of the pipe. The manufacturing phase is the second largest contributor to the emissions and was found to be (on average) five times bigger for CS pipes than any of the non-metallic pipe technologies assessed in this study. The use of stronger and lighter fiber reinforcements (e.g., carbon fibers) to substitute conventional glass fibers in RTP pipes enabled a noticeable reduction in the product weight. However, the potential in reduction of overall emissions was outweighed by the exceedingly high carbon intensity of carbon fibers. The results of this study are supporting an ongoing strategy for mass deployment of nonmetallic pipes (a traditional driver in reducing operating costs) and provide a path for cleaner production and distribution of hydrocarbon resources. The conclusions of this work could be further developed by accounting for the operational phase of the pipes in question.

Effect of SiO2 on microstructure and mechanical properties of composite ceramic coatings prepared by centrifugal-SHS process

For high-temperature, sand-bearing, and high-pressure water injection pipelines, failure of commonly used organic epoxy coatings occurs frequently, which needs to be solved urgently. Ceramic coating is excellent alternative to solve this problem, attributed to its high hardness, high temperature resistance, and corrosion resistance. However, ceramic coatings prepared till date suffer from some problems, such as high porosity, and poor toughness. To improve overall performance of composite ceramic coating, herein, ceramic-lined composite steel pipes were synthesized by centrifugal self-propagating high-temperature synthesis (centrifugal-SHS), via doping different concentrations of SiO2 in the Al/Fe2O3 reaction system. The microstructure and phase of composite ceramic coatings after addition of SiO2 were analyzed by optical microscopy with super depth of focus, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Effects of SiO2 on the density and porosity, microhardness and fracture toughness, compression-shear strength and crushing strength of composite ceramic coatings were investigated by Archimedes method, Vickers indentation microfracture method, shearing test, and squeezing test, respectively. Results showed that the introduction of appropriate amount of SiO2 reduced cooling rate of reaction system, thus improving the densification level and strength of coatings. Furthermore, in reaction system, FeAl2O4 phase disappeared, owing to excessive Al, which could improve corrosion resistance of composite ceramic coatings. The optimum doping concentration of SiO2 was found to be 4 wt%, in which composite ceramic coating showed excellent properties.

Investigation on alkali corrosion resistance of 310s + WC coatings prepared by PTA

ABSTRACT In order to prolong the service life of the water-cooled wall used in boilers of paper mills, explosive welded composite steel pipes are mostly used due to their excellent alkali corrosion resistance, but its technical requirements and costs are relatively high. In this paper, FSAN38 powder modelled on Sanicro38 composition and 310s stainless steel + WC powders is utilized to prepare a composite metal layer on 1020G surface by plasma cladding technology. Electrochemical corrosion and molten alkali corrosion experiments were carried out, then the microstructure and composition of the cladding layer were observed. Compared with explosion welded composite steel plate Sanicro38, it is found that the 310s+10%WC surfacing layer has the best alkali corrosion resistance, its electrochemical corrosion rate is 0.038184 mm a−1, and the corrosion rate in molten alkali salt is 1.01 × 104g (m2h)−1, which is 61.9% of Sanicro38.

Application of Grid-Work Girders of Grouted Oblique Steel Pipe Piles for Reinforcement of Embankments with Slope Deformation Failure

In special situations, the treatment plan for embankment failure is hindered by cracking and sliding failure in highway embankment slopes. For example, the prestressed anchor cable or bolt frame beam is not suitable as the absence of a hard anchorage ground layer, or slip deformation embankment cannot be removed and rebuilt to protect the existing sub-grade. An ideal solution in this situation is to use grid-work girders of oblique steel pipe piles. The grouting of oblique steel pipe piles is a method that uses a composite foundation of steel pipe piles to reinforce slopes. Specifically, grout is embedded into steel pipe piles and passes through the sliding surface. Grouting can change deformable soil into composite soil and protect steel pipes from corrosion. Steel pipe piles serve as reinforcement by applying anti-slide force directly onto the soil. By means of a successful example of slope deformation treatment, this work discusses the scope of the application, the stress characteristics, the changes in slope stability, and the reinforcement effects after slope strengthening. The results would benefit engineering projects involving similar slope failure treatments.

Strengthening Mechanism of Al2O3 Ceramic-Lined Composite Steel Pipe Prepared by the SHS Gravitational Separation Process

The Al2O3ceramic-lined composite steel pipes were produced by the SHS gravitational separation process (SHS-GS process) from Al, Fe2O3and Cr2O3as the raw materials within different reaction systems. The phase, composition, micro-structure and properties of ceramic coatings were investigated to discuss the strengthening mechanism of the composite steel pipe. The results showed that the phase composition of Al-Fe2O3-Cr2O3reaction system could be Al2O3and Fe-Cr alloy compared with the Al2O3-Fe-FeAl2O4phases of Al-Fe2O3reaction system, which led to the increase of strength and hardness of ceramic coating. Because the Fe-Cr alloy was formed instead of Fe element, and the addition of Cr2O3reduced the production of erodible FeAl2O4. The transition structure consisted of ceramic coating-transition layer-steel pipe was formed, and in its direction the Al and O element contents decreased, the metallic Fe and Cr increased. Therefore, the transitional changes of all the element contents could decrease the stress difference between the layers, and increase the bonding strength of the composite steel pipe.

The study of a novel ultrasonic A-scan signal processing method based on fractal theory

Concerning ultrasonic non-destructive testing of ceramic-lined composite steel pipes, a novel bonding flaw locating method based on fractal dimension is proposed. Ultrasonic A-scan method is used on different positions of the composite steel pipe test piece. The fractal dimension of each curve of ultrasonic vibration signal is calculated. The transformation of each fractal dimension is compared and abnormal positions where bonding defects potentially exist are detected. The result indicates that ultrasonic A-scan signal has an excellent fractal conduct characteristic. It is feasible to compare fractal dimension of signal with the normal range and find out abnormal positions, which can provide basis for follow-up inspections.

Microstructure, mechanical properties and corrosion of ceramic-lined composite steel pipe prepared by centrifugal-SHS process

A ceramic-lined composite steel pipe (CLCSP) was fabricated with N80 steel tube as substrate by self-propagating high-temperature synthesis and centrifugal casting technique. The constituent phases and microstructure of the ceramic layer were analyzed, and the mechanical properties of CLCSP were measured, including hardness, crashing strength, compression-shear strength and tensile performance. The wear and corrosion behaviors between CLCSP and N80 steel tube were also compared. The results show that ceramic layer consists of columnar dendrites of Al2O3 and spinel-like structure FeAl2O4, CLCSP has a much higher hardness, squeezing deformation resistance, wear and corrosion resistance as compared with N80 steel tube.

Development of Restraint Joints for Composite Steel Pipe and Investigations for Their Performance Evaluation Index

Development of Restraint Joints for Composite Steel Pipe and Investigations for Their Performance Evaluation Index

A study of ceramic-lined composite steel pipes prepared by SHS centrifugal-thermite process

Al2O3 ceramic-lined steel pipe was produced by self-propagating high-temperature synthesis centrifugal thermite process (SHS C-T process) from Fe2O3 and Al as the raw materials. The composition, phase separation and microstructures were investigated. The result showed the ceramic lined pipe is composed of the three main layers of various compositions, which were subsequently determined to be Fe layer, the transition layer and the ceramic layer. Fe layer is composed of austenite and ferrite, the transition layer consisted of Al2O3 ceramic and Fe, the ceramic layer consisted of the dendritic-shaped Al2O3 and the spinel-shaped structured FeAl2O4.

Microstructure and Mechanical Properties of ZTA Ceramic-Lined Composite Pipe Prepared by Centrifugal-SHS

A type of zirconia-toughened alumina (ZTA) ceramic-lined composite steel pipe was fabricated by using self-propagation high-temperature synthesis and centrifugal casting technique. The microstructure and phase constituents of ZTA ceramic layer were analyzed by means of optical microscope, scanning electron microscope and X-ray diffractometer (XRD). The fracture toughness of ceramic layers and mechanical shock of Al2O3 and ZTA ceramic-lined composite pipes were measured using Vickers indentation microfracture method and the repetitive impacting method. The results show that the phase constituents of ZTA ceramic layer were Al2O3, FeAl2O4 and t-ZrO2 phases, and no m-ZrO2 phase was detected by XRD. Addition of ZrO2 reduced the width of Al2O3 dendrites and led to formation of a microstructure with fine ZrO2 particles distributed at boundaries of Al2O3 dendrites. The fracture toughness was increased from 0.56 MPa m1/2 of Al2O3 ceramic layer to 5.74 MPa m1/2 of ZTA ceramic layer. The mechanical shock resistance at the center of the ceramic-lined composite pipe was increased from twice to 19 times after addition of ZrO2 into the Al2O3 matrix.

Effects of Nano-TiO<sub>2</sub> on Microstructure and Properties of Ceramic-Lined Composite Steel Pipes Produced by Centrifugal Self-Propagating High-Temperature Synthesis

In order to improve the density and mechanical properties of ceramic-lined composite steel pipes produced by Centrifugal Self-propagating High-temperature Synthesis. Composite steel pipes were prepared by the method of centrifugal-SHS on the basic of Al-Fe2O3 system. With the condition of adding 6% SiO2 and 4% Na2B4O7, the effect of different amount of nano-TiO2 on the density and the mechanical properties of composite steel pipes was studied. By means of SEM analysis, XRD and mechanical tests, the results show that the ceramic layer consists of main crystal phase of α-Al2O3, with small amount phases of FeAl2O4, Al2SiO5 and B2O3. The surface of ceramic layer is smooth, without obvious crack and with good density. The shearing strength of the ceramic layer and the crushing strength of the composite pipe were 13.5 MPa under 8% (in mass) nano-TiO2 and 525Mpa. The density of ceramic layer is up to 94.2% under 8% (in mass) nano-TiO2.

The Construction Technology and Control Points of Composite Bailey Beam and Fastener-Style Steel Pipe Group Support

The composite bailey beam and fastener-style steel pipe group support possesses the characteristic of low security risk and construction cost. But its vertical crossing scope of the working area is comparatively huge with many factors which would influence the construction. Therefore, it is required to organize the construction meticulously, improve the construction technology and clarify the construction control points.

Study on Properties of Ceramic-Lined Steel Pipes Prepared by Centrifugal Self-Propagating High-Temperature Synthesis

Ceramic-lined steel pipes were made by adding nano-SiO2, Na2B4O7 additives into (Al-Fe2O3) combustion system on the basic of using centrifugal-SHS. The effect of nano-SiO2 on the density and corrosion-resistance of ceramic-lined steel pipes were studied with the condition of adding 4% Na2B4O7. The density was tested by Archimedes principle and the corrosion resistance was tested by weight-loss method. It is shown that the best density of composite steel pipes is got by adding 6% nano-SiO2 and the best corrosion-resistance is got by adding 4% nano-SiO2.

Study on Micstructure and Properties of Ceramic- Lined Composite Steel Pipes Produced by Centrifugal-SHS Process

The Al2O3 ceramic-lined steel pipes were made by SHS centrifugal process. The microstructure and phases in ceramic layer were investigated by SEM and X-ray diffraction, microstructure of the ceramic was observed with metallurgical microscope and compression-shear strength of the ceramic was tested by electronic universal testing machine, respectively. The results show that composite steel pipe is composed of three layers, including inner ceramic layer, transition iron layer and outer metal wall, compression-shear strength of the ceramic layer is up to 23 MPa. The percentage of porosity was tested by archimedes principle, it shows that porosity of ceramic was 5%; corrosion resistance of ceramic was tested by mass-loss method, corrosion resistance of ceramic coating is 0.95g/(h•m2).

Properties of Ceramic-Lined Composite Steel Pipes and their Application

Properties of Ceramic-Lined Composite Steel Pipes and their Application

Stainless steel lined composite steel pipe prepared by centrifugal-SHS process

The tension properties, thermal expansion coefficient, microstructure and the causes of crack formation of the stainless steel layer in the composite pipe made by centrifugal-SHS process were investigated. It was shown that the tensile strength is 316 MPa and the percentage elongation is 5–8%. The nonmetal inclusions make the stainless steel brittle. In the brittle stainless steel layer the crack is caused by the thermal stress. The stainless steel mainly composed of austenite phase which grows in columnar grain in the radial direction of a carbon steel pipe and a thin ferrite layer was distributed between the austenite phases. The intermetallic compound AlNi precipitates in the ferrite phase and sigma-phase precipitates at the phase boundarie between the austenite and ferrite.

THIN-WALLED LARGE-DIAMETER COMPOSITE PIPES.

A South African steel pipe manufacturer approached the Department of Civil Engineering at the University of Pretoria to determine the behaviour of composite steel and concrete pipes to be used in lieu of solid steel pipes. Under South African conditions great cost savings can be made by reducing the steel wall thickness and making up for this by adding a concrete layer. The large-diameter composite pipes consist of a thin steel pipe covered by reinforced concrete, which is then wrapped in high-density polyethylene. The investigation was conducted on large-diameter steel pipe sections and the results obtained used to determine the required stiffness for a composite pipe. A mathematical model was developed for designing composite pipes with stiffness equivalent to that of the steel pipes required by the American Water Works Association Manual M11. This model was calibrated with load deflection tests conducted on composite pipes. Some interesting aspects of this investigation will be discussed in this paper.

Stainless steel lined composite steel pipe produced by centrifugal SHS process

Stainless steel lined composite steel pipe produced by centrifugal SHS process