Defects In Pipes Research Articles

Magnetic Permeability Perturbation Testing for Internal Axial Cracks in Small-Diameter Thick-Walled Steel Pipes

Special geometric features and complex working environments render the internal defects of small-diameter thick-walled steel pipes “easy to expand, difficult to detect”. In this paper, a magnetic permeability perturbation testing (MPPT) method is proposed to assess the internal axial cracks of small-diameter thick-walled steel pipes. The mechanism of the MPPT method and its corresponding probe and magnetizer are introduced, and its feasibility is verified through a series of simulations and experiments. Experiments conducted using different sizes of small-diameter thick-walled pipes show that this method offers good performance with respect to the detection of internal axial cracks. Additionally, both diameter and wall thickness significantly affect the MPPT signal. To a certain extent, a greater wall thickness or a smaller diameter brings about a weaker signal. This method does not benefit from the lift-off effect, nor is it limited by the skin effect, which has great practical value as a supplement to the evaluation of thick-walled steel pipes.

Structural Optimization and Simulation of a Magnetic Leak Detection Device for Streak-like Defects in Oil Pipes

Striped defects are a common type of defects in oil pipelines, divided into horizontal and longitudinal stripes, and it is difficult to accurately quantify the results of conventional pipeline leakage magnetic detection to correspond to the type of defects and their extent. In this paper, a new type of oil pipe non-destructive testing equipment is proposed and designed based on the principle of magnetic leakage detection using three-dimensional finite element simulation, and the magnetic field distribution inside the equipment is simulated using ANSYS finite element analysis software to provide original data reference for the development of the new equipment.

An Overview of the Application of Fiber-Reinforced Cementitious Composites in Spray Repair of Drainage Pipes

The structural performance of buried drainage pipes is gradually deteriorating under the influence of external loads and chemical and microbial corrosion. It is crucial to reinforce them and improve their bearing capacity for safe use. One of the important technologies used to extend the service life of deteriorated pipes is the use of fiber-reinforced cementitious composites (FRCC) for spray repair. Combined with the current situation of drainage pipes, this article introduces the basic properties of FRCC, briefly describes the requirements for material performance for drainage pipe spraying rehabilitation, reviews the structural bearing capacity of drainage pipes repaired by spraying with FRCC, and discusses the relevant research and engineering applications of the spraying method. Studies show that FRCC has high strength and corrosion resistance, and excellent sprayability. The structural performance of the host pipe is significantly improved after repair, but measures should be taken to enhance the interfacial bonding performance during the repair. In the design of the liner wall thickness, there is no unified calculation theory, and the existing methods have not considered the influence of secondary load on the structure. It is recommended to combine the type of pipe defects and the degree of deterioration in further study.

Methods of increasing the corrosion resistance of underground water supply pipelines

The main causes of premature destruction of the pipeline network of water supply and drainage within the territory of Ukraine are the following: factory (metallurgical) defects of pipes, assembly defects (as a rule, they occur during installation work directly on the object), corrosion damage and destruction of the pipe body and welded connection, natural and deformational aging of metal, external loads and internal excess stresses, lack of high-quality anti-corrosion protection, long (exceeding normative) service life of pipelines that are in direct contact with a corrosive-aggressive environment, etc. Analysis of the general condition of centralized water supply and centralized water drainage systems for 2021. Carried out for 19 regions and the city of Kyiv. Based on the analysis, the following conclusions were drawn: centralized water supply covers 98.7% of cities (absent in 4 cities), 90.3% of rural settlements (absent in 46 rural settlements), and 23.5% of rural settlements, 67.4% of rural settlements and 1.5% of rural settlements. To ensure the development and reconstruction of systems of centralized drinking water supply and centralized water drainage in populated areas of Ukraine and to provide the population with quality drinking water in sufficient quantity, the Ministry of Regions has developed the State-wide target program "Drinking water of Ukraine", which provides for the implementation of more than 1,747 infrastructure projects in the regions during 2022-2026 years In addition, the following measures are recommended for the development of water supply and drainage enterprises: the creation of effective response systems in case of emergency situations, in particular, a logistics chain for the supply of the necessary welding and assembly resources (materials, equipment, labor, etc.); attraction of investments for the modernization of water supply and treatment facilities of the central drainage system; carrying out scientific and research works for the purpose of modernization of engineering facilities for wastewater treatment; modernization of pipeline structures and treatment facilities with the involvement of modern welding and assembly technologies and materials. In addition, in order to increase the reliability of water supply and sewage networks, it is now necessary to carry out certification and inspection of pipelines. Knowing the degree of wear and tear of the pipe wall and the service life, you can calculate the nominal pressure of the pipeline and make a decision about its replacement or rehabilitation. Using the failure criterion for "critical" points, it is possible to predict the complications of network operation, model redundancy for them, and optimize their operation. It is proposed to equip specialized mobile laboratories on the basis of water utilities, which allow network diagnostics and emergency cleaning of pipelines and water disinfection. Specialists of the Ministry of Development of Communities and Territories of Ukraine carried out systematic work on assessing the technical condition of water supply networks. The materials officially provided by the Ministry of Health of Ukraine and the Ministry of Environmental Protection and Natural Resources of Ukraine served as the basis for such works. The curator of this work was the State Enterprise "Scientific-Research and Design-Technological Institute of Urban Economy" (Kyiv).

Quantitative Study of Sensor-Pipe Distance in Noncontact Magnetic Detection of Ferromagnetic Pipelines

Non-contact magnetic detection technology has great application potential in buried oil and gas pipelines due to the non-contact online detection of pipeline damage. However, the non-contact magnetic detecting signal is affected by the distance between the magnetometer and the ferromagnetic pipeline, leading to missed detection of pipe defects. It is essential to calibrate the detection height for the non-contact magnetic detecting signal. In this paper, the spatial analytical model of non-contact magnetic signals above ferromagnetic pipelines is established. Then, a quantitative variation law of non-contact magnetic detecting signals is obtained under different pipe diameters and internal pressures. Next, a signal calculation model based on the detection height h is established. A detection height correction method is proposed to eliminate the influence of detection heights on the magnetic detecting signal. An experimental investigation is carried out to validate the accuracy of the numerical calculation results and correction method. The results indicate that the magnetic detecting signal has a second-order exponential relationship with the detection height h within 0.1 m - 2 m. The average error of the signal correction model is 6.37%. The modified magnetic detecting signal via the signal correction method can reflect the damage status of ferromagnetic pipelines.

Experimental Research on Pipeline Corrosion Monitoring Technology Based on FSM

The field fingerprint method (FSM), a new online corrosion monitoring method, has a good application prospect. Of all the corrosion defects of pressure pipes, local small corrosion pits are the most commonly seen, and it is also the focus of FSM research. Based on the FSM method, this paper conducts experimental research on the common round and rectangular small corrosion pits of pressure pipes. The results show that the FSM method is sensitive to small volume defects, and the small corrosion pits with the minimum detectable depth of 0.5 mm can accurately reflect the defect growth process, this being of great significance to the safe operation of pipelines.

Torsional mode magnetostrictive patch transducer with TPSMs for liquid-filled pipes inspection

T (0,1) mode guided waves have no axial or radial vibration displacement. Therefore, the energy leakage is small in liquid-filled pipes, which is suitable for detecting the axial defects of the liquid-filled pipes. Fe–Co materials with high magnetostriction coefficient is fabricated. Its magnetic properties are tested. The size and distribution of static magnetic fields generated by different permanent magnets are verified by simulation. A new torsional mode guided wave magnetostrictive patch transducer with tile-shaped permanent magnets for defect detection of the liquid-filled pipes is proposed. The detection effect of the transducer on the liquid-filled pipes under different pressures is tested through experiments. The proposed transducer consists of four tile-shaped permanent magnets, eight triangular yokes, a coil, and two magnetostrictive patches. Four groups of tile permanent magnets are symmetrically distributed around the patch according to the polarity. Magnetic yokes are installed at both ends of each group of tile permanent magnets. The experiment verified that the magnetostrictive patch transducer realize the excitation and reception of guided wave signals in the magnetostrictive patches. The amplitude and signal-to-noise ratio of echo signals is improved. The position of pipe defects is determined according to the propagation time of guided wave. The influence of different pressures in the liquid-filled pipes on the amplitude of guided wave is verified.

Research on Classification and Recognition of Industrial Stainless Steel Welded Pipe Defects Based on Convolution Neural Network

For the classification and identification of industrial stainless steel welded pipe defects, a combined method of STFT and CNN based on vortex test is proposed. First, the collected original eddy current signal is STFT transformed to obtain a two-dimensional time-frequency map. Then, the two-dimensional time-frequency map was input into the two neural networks VGG-16 and GoogLeNet for model training, selecting a more accurate network model under the condition of the same learning rate. The trained network model is then classified using different learning rates. The results show that with the learning rate of 0.0001, the VGG-16 training model is better than the GoogLeNet training model, which has a certain reference significance for the classification and identification of defects in industrial stainless steel welded pipes.

Analysis of Interaction between Interior and Exterior Wall Corrosion Defects

With the increase in oil and gas pipe mileage, various corrosion defects inevitably occur, so the mechanisms and the applicability of the interaction corrosion defects are investigated. The ANSYS Workbench software is used to study the three double defect pipe models based on the exterior wall, the interior wall, and the interior and exterior wall. First, the distribution of the stress nephogram is investigated. Second, the failure pressure is obtained through the load step based on the variety of the failure pressure. Finally, the critical distance formula of the different types of double defect pipe models is fitted using MATLAB software, and its applicability and accuracy are verified. The results show that the equivalent stress is divided into two areas; with increasing defect depth and defect length, the critical distance increases and the growth rate increases; by fitting the critical distance formula of the three double defect pipe models, the multiple function formula of defect depth and defect length under different defect location distribution is obtained, with high accuracy. The critical distance ratio is introduced to compare 150 sets of data of the 3 models for conservative calculation; the three models perform well in the critical distance ratio and the double defect pipe model based on the exterior wall is the most conservative.

Microbiologically induced concrete corrosion in the cracked sewer pipe under sustained load

Microbiologically induced concrete corrosion (MICC) and stress crack are the most common structural defects in concrete sewer pipes. To investigate the microbial corrosion behavior of cracked concrete pipes under sustained loading, coupons with no load, 100% D-Load, and 120% D-Load were pre-adjusted to a suitable environment for acidophilic sulfur oxidizing bacteria (ASOB) colonization, and then placed together in a microbial chamber for 90-day accelerated corrosion. The corrosion variances of these coupons were compared in terms of surface morphology, crystalline violet staining, pH evolutions, crack width changes, as well as characterization results including Scanning Electron Microscope- Energy Dispersive Spectrometer (SEM-EDS) and X-ray Diffraction (XRD). It was found that the stress level slightly accelerates the pH drop on the coupon surface, positively correlates with the corrosion product content of the semi-corrosive layer, and causes stress-corrosion cracking of the semi-corrosive layer, but has little effect on corrosion loss. Stress-corrosion effects were only found in the semi-deteriorated layer of the stressed coupon, but no significant acceleration effect on corrosion rate was observed. This is explained by the fact that MICC is a non-diffusive corrosion where the semi-deteriorated layer is rather thin. Thus, cracking or not of the semi-deteriorated layer does not affect the corrosion rate. This study improves understanding of the service deterioration of sewage pipes.

Study on the Relationship Between Thickness Measurement and Strength Defect of Buried Pipeline

Based on the principle of electromagnetic eddy current testing, aiming at the problems of heavy workload and difficult location of defects in the periodic inspection of buried pipelines, the eddy current distribution of pipelines, probes, and defects is modeled and simulated by using ANSYS EM simulation software, the correlation model between pipeline parameters, excitation signals, and received signals is established, and the quantitative relationship between pipeline wall thickness parameters and eddy current distribution is clarified. Based on the accuracy and engineering application ability, the through pipe wall thickness detection device is optimized, and the structure of the eddy current probe is improved. The experimental results show that the improved eddy current probe can improve the detection accuracy of 6.9% in detecting the induced eddy rheology in the workpiece and effectively improve the efficiency of pipe wall thickness defect location and pipe radius detection, which can provide a new reference for the regular detection and troubleshooting of buried pipelines.

Review on Effect of Plumbing System in Construction

Abstract: Effect of Plumbing System in Construction plays an important role. Pipe damage and defects are part of pipe maintenance. There is no chance or short circuit during Plumbing maintenance. Plumbing and plumbing involves various components that should be examined, so there is a chance that one or the other component may break. These components can cause some temporary problems as well as long-term structural damage due to water seeping into walls and floors. To avoid such problems, it is important to fix plumbing problems as soon as they are discovered. The durability of the pipe system depends on the quality of its parts and the installation skills of the installers. No plumbing system, however well designed, can be expected to operate safely or hygienically unless the products or materials used are satisfactory. The opposite is also true if the best quality products or materials are used but incorrectly installed, the system will fail. Therefore, proper research and its operation will ensure optimal success and satisfactorily meet the expectations of Effect of Plumbing System in Construction. The efficiency and quality of plumbing depends on the expectations of the home owner, the condition of the pipe work performed and its plumbing activities.

Numerical sensitivity analysis of corroded pipes and burst pressure prediction using finite element modeling

Accurately predicting the failure pressure for corroded pipes transmitting natural resources such as oil and gas is crucial to prevent catastrophic failure and save costs. Several parameters affect the pipe's burst pressure, precisely the defective width, which is essential yet under debate. In this study, parameters such as the corrosion depth (25%, 50%, and 75%), angle (10⁰, 15⁰, 45⁰ and 90⁰), and length-to-diameter ratio “Lc/D" (0.25, 0.5, 1 and 1.5), were numerically investigated through sensitivity analysis, besides the pipes' size “D/t" ratio (16.19, 23.67, 42.64 and 79.79). The study also explored the adequacy of the previous burst pressure predicting models and proposed a new model through FE modeling. The results revealed that defect level significantly reduced the burst pressure regardless of defect angle, length, and pipe size. The defect angle ranges from 10⁰ to 45⁰, and the Lc/D ratio is less than 1, significantly impacting the burst pressure reduction for shallow and deep defects (25% and 75% wall loss). However, this impact disappears at the Lc/D ratio equals one. The findings showed that the old predictions, ASME B31G and RSTRENG, were more conservative than the newer models, DNV and Leis, for shallow defects and non-conservative for deep defects with intermediate lengths. The models that considered the material's strain hardening, such as Shaui, Leis, Ma, phan, and Netto, enhanced the predictions compared to the old ones, especially at extended corrosion. Finally, the design charts through the proposed model were generated for further adoption by codes.

Ultrasonic phased array detection method for butt fusion welding defects of HDPE pipes

The welding joint is the weak link of the high-density polyethylene pipeline. The continuous development of ultrasonic phased array technology is expected to replace traditional non-destructive testing methods. In this paper, ultrasonic phased array technology is used to detect the defects of butt fusion welding. The results show that the ultrasonic phased array can distinguish between metallic and non-metallic inclusions, and the inclusion size can be displayed. Besides, insufficient fusion defects have no obvious defect features in the sector scan results. The types of insufficient fusion defects can be judged from the end-face line scan results.

Terahertz Identification of Hot Melting Joint Defects in Polyethylene Pipe Based on Wavelet Scattering Network

Terahertz Identification of Hot Melting Joint Defects in Polyethylene Pipe Based on Wavelet Scattering Network

Зміцнення інструменту для холодної роликової прокатки корозійностійких труб

The work is devoted to a topical technical problem - to increase the wear resistance of pipe tools for cold roller rolling of corrosion-resistant pipes, due to its significant cost and difficult working conditions. It is proposed to improve the technology of heat treatment of rolled tools for the production of corrosion-resistant pipes (mandrels, rollers, support strips) from steels 4Х5МФ1С and 60С2ХФА. Instead of the usual technology - tempering with tempering, tempering with tempering and subsequent ionic nitriding in plasma of two-stage vacuum-arc discharge in a modified installation "Bulat-6" in the laboratory of plasma technology. The microstructure of special samples of these steels on a scanning electron microscope (SEM) at different magnifications was studied. Their microhardness was determined using a microhardness tester PMT-3. A comparison of the microhardness of the samples after traditional treatment and the proposed. The wear resistance of the actual tool (mandrels made of 60С2ХФA steel) for cold roller rolling of particularly thin-walled corrosion-resistant pipes was studied directly during industrial tests in the factory. Studies of the microstructure on the REM of the nitrided layer after ion-plasma nitriding revealed a finely dispersed very strong ε-phase. Due to its presence in the surface layer, the surface hardness of nitrided parts increases due to the formation of stable in the process of heating carbides, nitrides, carbonitrides. Steel acquires high hardness on the surface, high wear resistance, high endurance, corrosion resistance. Tests of mandrels in the factory, which were additionally subjected to ionic nitriding, showed an increase in their stability by 25-30%. Also reduced the cost of processing the manufacture of pipes and improved the quality of the inner surface of the pipes (absence of films, cuts and other defects of corrosion-resistant pipes). Replacement of steel 60С2ХФA with secondary hardening steel 4Х5MФ1С for the manufacture of rollers and support bars in addition to improving the quality of the inner surface of the pipes increased the stability of the tool by 2.7-3 times. Keywords: rollers, support laths, mandrels, cold rolling, heat treatment, ionic nitriding.

Wastewater pipe condition rating model using K- Nearest Neighbors

Risk-based assessment in pipe conditions mainly focuses on prioritizing the most critical assets by evaluating the risk of pipe failure. This paper's goal is to classify a comprehensive pipe rating model which is obtained based on a series of pipe pipe, external, and hydraulic characteristics that are identified for the proposed methodology. The traditional manual method of assessing sewage structural conditions takes a long time. By building an automated process using K-Nearest Neighbors (K-NN), this study presents an effective technique to automate the identification of the pipe defect rating using the pipe repair data. First, we performed the Shapiro Wilks Test for 1240 data from the Dept. of Engineering & Environmental Services, Shreveport, Louisiana Phase 3 with 12 variables to determine if factors could be incorporated into the final rating. We then developed a K-Nearest Neighbors model to classify the final rating from the statistically significant factors identified in Shapiro-Wilks Test. This classification process allows for recognizing the worst condition of wastewater pipes that need to be replaced immediately. This comprehensive model is built according to the industry-accepted and used guidelines to estimate the overall condition. Finally, for validation purposes, the proposed model is applied to a small portion of a US wastewater collection system in Shreveport, Louisiana.

Numerical analysis of repaired wall loss defect pipelines for optimum composite wrap thickness

The paper presents the numerical analysis of failure pressure of wall loss defect metallic pipelines and validate it with experimental results. An optimization of composite thickness for repair of wall loss defect pipeline is also carried out using numerical analysis. A nonlinear explicit FE code with constitutive models for metallic steel and composite material to failure modelling was used. Three different cases: non-defective pipe, wall loss defective pipe and composite repaired of defective pipe are considered. It was found that the numerical results are in good agreement with the analytical results in all the three cases. The theoretical failure pressure determined by ISO/TS 24817 standard for wall loss defect pipe is highly conservative compared to the numerical failure pressure for the given composite repair thickness. Additionally, the numerical study on optimization of repair thickness revealed that lower composite repair thickness can also sustain the designed failure pressure (composite repair thickness of 8.4 mm can sustain the same designed pressure instead of 16.1 mm thickness), which implies there is scope to further reduce the composite thickness, which ultimately reduce the repair cost.

Method of non-contact detection of defect in coated cylinder

The method of non-contact detection of defects in a ferromagnetic cylinder is proposed. This method is designed to test of corrosion or mechanical damages of underground and underwater pipelines metal. This can be used to find defects in long cylindrical objects such as bars, wires, tires under insulation and process pipes under coatings. The results of calculations of the effect of a steel pipe defect on the distribution of the magnetic field are presented. The procedure for excitation of a rotating magnetic field, its reception and visualization of field anomalies to detect cylinder defects is described.

Ultrasonic guided wave testing on pipeline corrosion detection using torsional T(0,1) guided waves

Ultrasonic guided wave testing (UGWT) is used in rapid screening to detect, locate and classify corrosion defects. This non-destructive testing technique can perform wide-range inspection from a single point, thus reducing the time and effort required for NDT. However, the mode conversion phenomena and the dispersive nature of the guided waves make corrosion detection difficult. Hence, the parametric studies on the response signals of a T (0, 1) wave from pipe defects were presented in this paper. Firstly, a mathematical model of 6-inch schedule 40 pipes was developed. The corrosion profile of various geometries was then constructed on the outer surface of the pipeline by varying the circumferential length and depth. The numerical study was performed to analyse the characteristics of the response signals when a torsional guided wave impinges on the corroded pipelines. A five-cycle Hanning tone-burst signal with a central frequency of 30k Hz was used throughout the study. The results demonstrated that mode conversion to a flexural mode F (1, m) occurs when the stimulated T (0, 1) strikes non-symmetric defects. Nonetheless, as the circumferential extent of the corrosion increased, the response signals tended to behave symmetrically, and there was less mode conversion detected. Thus, the presence of flexural mode F (1, m) can be used as the criteria to distinguish symmetric and asymmetric faults. In addition, the results demonstrated that the reflection coefficients increase monotonically with the defect's depth due to the increases in the estimated cross-sectional area loss (ECL). As a result, a more significant proportion of the transmission wave was reflected. These findings serve as guidelines for on-site inspections. With the known speed of guided wave propagation, it is possible to precisely forecast the position of faults.