Joints Of Pipelines Research Articles

Methods for protecting corrosion of the inner surface of steel vitrified pipes during welding

ABSTRACT In work corrosion problems of welded steel vitrified pipelines and ways of their protection under the action of high mineral water with hydrogen sulphide (water conduits) of oil-compressor stations are considered. It is established that in order to eliminate the harmful effect of microalloying by boron of the welding seam, it is recommended to use the mentioned above welded joints of such pipelines as well as their repair. In view of the presence of a glass coating, it is recommended that extreme safety precautions be taken when installing such pipelines, in order to avoid disruption of the continuity of the glass coating.

Wine-processing waste sludge permeable reaction barrier utilized to block a gasoline plume in a simulated aquifer.

Oil leakage from gas stations in Taiwan is commonly caused by the corrosion of oil tanks or loose pipeline joints, contaminating the soil and groundwater near the gas station. Wine-processing waste sludge (WPWS) does not contain toxic substances and has a high organic matter content. Thus, it has high affinity for methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX), being suitable for application in preventing and controlling groundwater pollution. In this study, a permeable reaction barrier (PRB) constructed utilizing WPWS in a large water tank was designed to simulate the diffusion and blockage of gasoline plumes in an aquifer. The constructed WPWS PRB had a rectangular shape with a thickness and height of 9 and 60 cm, respectively. The depth in the aquifer was adjusted to 50 cm. MTBE was detected in the aquifer downstream of the WPWS PRB every day during the experiment; however, the maximum concentration detected was only 5.33 ppb. BTEX were only detected on 3 days during the experiment and had maximum concentrations of 1.76, 2.28, 0.34, and 0.60 ppb, which are below the water quality control standards.

Welding of ring joints of field pipelines with internal corrosion-resistant surfaced layer

The purpose of this work was to study the issues of ensuring the standard quality indicators of installation of welded pipes of field pipelines with a deposited layer of high-chromium steel. The research was performed on pipes made of steel 09G2S of the K48 strength category with a diameter of 258 mm and a wall thickness of 6 mm. The formation of the deposited layer on the inner surface of the pipe ends was performed by electric arc welding in protective gases with a wire SV-12X13 with a diameter of 1.2 mm. Welding of ring joints of pipes was performed with LB-52U type E50A electrodes according to GOST 9467 in accordance with the developed technology. Experimental testing of welding technology with an assessment of the quality of the resulting welds and their corrosion resistance was evaluated using non-destructive and destructive testing methods. Research results have shown the possibility of obtaining a corrosion-resistant welded joint with appropriate quality standards. Regulatory requirements for the welded connection of pipes with an internal surfaced layer were defined, which can be used in the implementation of projects for the construction of field pipelines with this design. It was shown, that to provide normative values of mechanical properties of welded joints of pipes with internal weld layer requires the development of additions to existing welding technology to the preparation of pipes prior to welding and temperature control prior and concomitant heating, to avoid embrittlement of the metal of the root seam layer when its alloying.

The study of the influence of technological parameters of the impulse process on the formation of the weld metal and the microstructure of the heat-affected zone

With prolonged use of metal structures, the likelihood of their mechanical destruction increases. This is largely true of welded joints of pipelines. One of the promising ways to solve the issue of increasing their service life is the development of welding methods based on the use of pulse control of the energy parameters of the process. The pulsed welding mode allows for controlled heat input to the weld zone, control the melting mode of the electrode metal and the formation of the weld metal structure and the heat-affected zone (HAZ).
 Two types of metal transfer from the electrode to the weld pool were used in the work: with short circuits and without them, that is, welding was performed on a "long" arc. At a constant feed rate of the electrode wire, the welding mode was changed by changing the shape of the current-voltage characteristics of the power source.
 It is established that with increasing pulse-arc welding frequency, pulse-arc welding on the effect of influence on the HAZ metal approaches the process of welding by a stationary arc. The results of metallographic studies showed a slight decrease in the total width of the HAZ with an increase in frequency to 50 Hz. A similar trend is observed for the area of ​​coarse-grained in the HAZ. However comparedwith a stationary welding process, the width of this section decreases more significantly - by 25 ... 30%. Thus, in the case of welding pipe steels due to the application of technology with a pulsed process, there is a prospect of influencing the structure of the HAZ overheating aria at different frequencies and relatively small linear energies (6.0 ... 6.2 kJ / cm). From a practical point of view, this makes it possible to reduce the proportion of an unfavourable, non-plastic overheating zone in the HAZ, which is important for cases of repair of thinning of the pipe walls during the surfacing of defects in an existing pipeline in a mechanized manner.

Structural condition and fatigue damageability of welded joints of steam pipelines

The Paton Welding Journal, 2020, №06. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

Stress Distribution in Pipe Samples of Gas Pipelines with Welded Joints

Напряжения в зоне термического влияния и сварного соединения связаны с наличием внутренних напряжений, возникновение которых связано с различными причинами. Основными из них являются неравномерность нагрева и усадки сварного шва, а также структурные изменения металла и околошовной зоны в процессе сварки. Эти напряжения могут складываться с эксплуатационными напряжениями, что в свою очередь приводит к ускорению скорости зарождения трещин в зоне сварного соединения. Произведена оценка двухосных напряжений в основном металле и в зоне сварных соединений магистральных трубопроводов на основе явления акустоупругости с использованием трех типов волн различных поляризаций (продольной и двух поперечных с ортогональной поляризацией) и электромагнитно-акустического преобразования ввода-приема ультразвуковых волн.В осевом направлении ближе к краям вырезки значения напряжений ниже, чем по центру, что объясняется уменьшением напряжений при удалении связей. Похожая картина наблюдается для окружного σ2 направления. В образцах со сварным соединением наблюдается резкое уменьшение значения относительных напряжений в зоне термовлияния сварного соединения по сравнению с напряжениями в области основного металла.

Моделирование дефектов при ультразвуковом контроле сварных соединений

The paper analyzes and develops proposals for optimizing the quality control of welded joints of technological pipelines using mechanized ultrasonic testing using the phased array method. The main advantage of the proposed method, in addition to identifying all existing defects, is the storage of information about scanning for a considerable time on electronic media, which makes it possible to use it in cases where a controversial situation arises, when an incident occurs, or if an accident occurs.

INFLUENCE OF REPAIR ON THE BASIS OF THERMAL TREATMENT ON CORROSION RESISTANCE OF WELDED CONNECTIONS SECTIONS OF LONG-TERM MAIN PIPELINES

Background The main cause of accidents of long-term operation main pipelines operating in the Republic of Belarus is the failure of ring welded joints due to the development of existing ones and the generation of new defects that lead to pipeline rupture or the formation of a corrosion fistula. The restoration of the visco-plastic properties of the welded metal is possible due to the repair work using the heat treatment method. At the same time, there are no studies on the effect of this method on the corrosion resistance of welded joints. Aims and Objectives To determine the effect of heat treatment on the corrosion resistance of sections of the ring welded joint of long-term operation main pipelines. Methods Corrosion studies were carried in accordance with the recommendations of State Standard 9.908 «Unified system of corrosion and ageing protection. Metals and alloys. Methods for determination of corrosion and corrosion resistance indices», State Standard 9.907-83 «Unified system of corrosion and ageing protection. Metals, alloys, metallic coatings. Methods for removal of corrosion products after corrosion tests», State Standard 9.905-82 «Unified system of corrosion and ageing protection. Corrosion test methods. General requirements». Results The use of heat treatment for repair work leads not only to the restoration of the visco-plastic properties of the welded joints of the long-term operation main pipelines, but also to a decrease in the corrosion rate by an average of 4 %. An increase in corrosion resistance is observed in all areas of the welded joint, which can be explained by the relative homogenization of the microstructure and the removal of residual stresses.

Ensuring industrial safety of pipelines with developed hard sections

Oil refining and petrochemicals have a wide demand for pipelines from heat resistant chromium steels. One of the main reasons for frequent failures of more stressed joints may be the presence of wide solid and brittle layers having significant areas in metal volume with maximum clusters of imperfections of metal structure and creating excessive concentration of additional residual deformations and stresses in welded joints, which are most saturated with defects inherent in welded joints. Presence of such extended sections leads to reduction of process strength of welded joints, increases tendency to formation of cold cracks and sharply limits time of laying of thick-walled welded joints of pipelines before subsequent high-temperature thermal treatment. The work carried out studies on welding pipe blanks in order to compare different methods of 5CroMo16 steel treatment during welding and determine the most efficient mode. Regularities of stressed state of different-module structural elements with wide solid layers are established.

Structural changes in the metal of welded joints of long-term operating steam pipelines

Structural changes in the metal of welded joints of long-term operating steam pipelines

Структурні зміни металу зварних з’єднань тривало експлуатованих паропроводів

Структурні зміни металу зварних з’єднань тривало експлуатованих паропроводів

Modelling and parametric study of a gasketed bell and spigot joint in a buried high density polyethylene pipeline

The performance of joints in gravity flow pipelines has recently been investigated since these elements influence the longevity of the pipeline system. A variety of pipe materials and joint configurations are available for gravity applications; for lined corrugated High Density Polyethylene (HDPE) pipelines, gasketed bell and spigot joints are the commonest configuration employed in North America. The purpose of the present research study is to develop a numerical model of this joint configuration that helps improve the understanding of its behavior by capturing the kinematics of the system while buried and subjected to surface load. The model provided estimates of springline rotation within 9% of the observed angle, and vertical displacement at the joint in the crown region within 8% of the experimental data from a previous research study. Other objectives include a parametric study to assess the influence of various factors that control joint performance such as surface load position and configuration, soil properties around the pipe, and the presence of pavement. The results from the parametric study indicated that the size difference of the loading pads employed in North America had little influence on the response of the jointed pipeline. It also confirmed that the single wheel pair configuration produces some of the largest demands across the joint compared to single and tandem axle configurations. The results demonstrated the significant influence that the soil and pavement have on the kinematics demands that develop across the joint due to surface loads.

Alternative design of buried pipelines at active fault crossings using flexible joints

The use of “flexible joints” in buried high-pressure pipelines is examined herein as an effective design technique for the mitigation of Permanent Ground Displacement (PGD) effects due to fault activation. Pipeline joints that are available in the industry today are considered in connection with the needs of high-pressure pipelines in areas of seismic faults. The efficiency of this novel technique is examined through a series of parametric numerical analyses for both strike-slip and normal faults, while its applicability in common engineering problems is examined through an economic-technical comparison with more conventional techniques. It is concluded that the use of flexible joints provides a cost-efficient design method, that can drastically reduce pipeline strains for medium to large fault displacements.

Investigation on the application and retention of intravenous infusion tools in hospitalized children

Objective To investigate the use of different tools of intravenous infusion and the issues associated with intravenous catheter indwelling in hospitalized children and to provide reference for clinical practices. Methods Using the convenient sampling method, from July 24th to 31st, 2018, the intravenous infusion treatment of children inpatients in 49 hospitals within the Beijing Children's Hospital Medical Association was selected for investigation. A self-designed Cross-sectional Questionnaire for Children's Intravenous Infusion and a photo of an intravenous infusion tool were used for data collection. Statistical analysis was performed using SPSS 17.0 software. Results During the data collection period, there were 18 316 hospitalized children in the 49 hospitals, among which there were 14 421 cases of infusions, with the infusions rate of 78.73%. The application rate of indwelling needle was 87.94%. The connector of venous catheter was mainly heparin cap connection (64.23%) . The infusion tools used in 6 398 cases (44.37%) were made by PVC and containing 2-ethyl hexyl phthalate (DEHP) . Aseptic transparent dressing was the main dressing choice. During catheter indwelling, there were some problems such as back-blood in the pipeline or infusion joint, incorrect clamping position of small clips, unclamping, and tube detachment. Indwelling needles had more problems than central venous catheters, including old blood returning in the tube and blood returning in the infusion connector. The difference between the peripheral indwelling needle and the central catheter was statistically significant (P<0.05) . Conclusions The rate of intravenous infusion in hospitalized children is relatively high. Although there are various types of intravenous infusion tools, the choice of infusion tools for children was mainly indwelling needle and heparin cap connection, and there were still room for improvement in catheter maintenance. Key words: Children; Intravenous infusion; Tool; Indwelling; Investigation

The assessment of the individual resource of the welded joint during repairs of the technological pipeline

The relevance of research is due to the necessity to develop recommendations for assessing the “individual” resource of welded joints of technological pipelines using non-destructive testing methods for the timely detection of welds with the smallest resource to ensure reliable operation of equipment and the inadmissibility of premature failure in the weld zone. The task is to develop recommendations for determining “individual”resource of welded joints of technological pipelines with a different level of edge displacement and imperfection by introducing correction factors into the modified Coffin-Manson equation based on the mechanical characteristics of the yield strength and strength, determined as a result of static tensile testing of samples of various sections of welded joints with maximum acoustic and magnetic signals according to the results of flux-probe and ultrasonic non-destructive testing. For research, 6 pipe fragments were selected made of steel 20 with dimensions of 159×7 mm and a length of 45 mm each. Fragments were welded together by different types of welding with different displacements of the edges of the welded elements. The authors developed recommendations for assessing the “individual” resource of welded joints of technological pipelines. It is shown that the introduction of correction factors depending on the amount of offset of the edges of the welded joint allows to increase the accuracy of the predicted durability of individual welds by 4% for manual and 11% for semi-automatic welding, respectively.

Development of self-protective powder wire with diameter of 1.6 mm for automatic welding of pipe-lines joints root

The results of self-protective powder wire with diameter of 1.6 mm are presented. The working purpose is to create small-section powder wire and its manufacturing technology, designed for automatic welding of the root layer of the seam of non-rotating joints of main pipe-lines transporting oil and gas with admixture of hydrogen sulfi de, and providing increase of at least 1.5 times the productivity of pipe welding. The forming rollers for the initial billet with diameter of 2.4 mm of two-bend powder wire are developed. The composition of the charge fl uxcored wire, providing the requirements of product development: reliable penetration of the root layer of the seam fi xed joints of pipe-lines with tensile strength of the weld metal at 490 MPa. Recommendations on the production technology of self-protective powder wire of two-bend design are developed.

Mechanical Response of Gasketed Bell‐and‐Spigot Joint of Concrete Pipeline under Multifield Coupling

Concrete pipe may suffer joint failure under the coupling effect of internal fluid and overlying load, which may lead to pipe leakage. Based on Abaqus and Fluent finite element software, a three‐dimensional refined model of drainage pipeline with gasketed bell‐and‐spigot joints and flow field model inside the pipeline was established. Fully considering the compression of the gasket during pipeline assembly and pipe‐soil interaction, the fluid‐structure coupling numerical simulation was carried out by using the MpCCI (Mesh‐based parallel Code Coupling Interface) platform, and the mechanical response of the concrete pipe joint under the multifield loads coupling effects of burial condition, traffic load, and internal fluid was studied. The accuracy of the coupling model was verified through the full‐scale tests that have been carried out. The influences of various factors on the circumferential stress and vertical deformation of the joint were mainly studied. The result reveals that the influence of different working conditions on the circumferential stress of the pipe joint is mainly concentrated on the crown and the invert of the joint, the areas vulnerable to tensile damage. The change of flow field leads to a slight difference in the vertical deformation of the joint, while variation in gasket hardness and cushion compactness has a certain influence on the vertical deformation of the joint. The change of buried depth has a negative correlation to the vertical deformation of the joint, and the change of load position has a significant nonlinear effect. The result provides a theoretical basis for further research on the mechanical mechanism of the pipeline joints during operation.

The use of magnetic flaw detection to control the offset of the edges of the welded joints of technological pipelines

The task was set of developing recommendations for identifying areas of displacement of the edges of the welded joints of abutting pipes, as well as identifying potentially dangerous sections of welded joints of technological pipelines by changing the normal component of the constant magnetic field. For research, 24 pipe fragments made of steel 20 with a length of 45 mm each were selected. The authors developed recommendations for identifying the presence and zone of displacement of the edges, as well as identifying potentially dangerous sections of welded joints of technological pipelines using the flux-gate control method. It is proposed to use the obtained maximum values of the normal component of the constant magnetic field for the objective detection of edge displacement zones and the determination of potentially hazardous areas. It was shown that the normal component of the constant magnetic field, is quite sensitive both to the displacement of the edges of the welded joints of the pipes and to the quality of the weld, its geometry, defectiveness and determines the above indicators with various characteristic values.

Impact of amplitude modulation of heteropolar square current pulses on formation of permanent joints in metal structures under residual magnetization

The work studies the impact of amplitude modulation of heteropolar current pulses on the formation of permanent joints of main pipelines done by manual shielded metal-arc welding. The results show that square pulsed current together with additional low-frequency current modulation facilitates formation of all weld layers in pipelines with residual magnetization. The work establishes that varying residual magnetization degree has no adverse effect on the quality of all layers of the permanent joints realized by modulated alternating square current, including their macrostructural and microstructural characteristics. This increases the technological stability of welding through elimination of electrode freezing during low-energy periods.

Impact of Mining Extraction on Above-Ground Pipelines

The issue of the impact of subsoil deformations on above-ground steel pipelines, especially district heating pipelines, located in mining areas in Poland was discussed. The pipelines constructed from steel pipes joined by welding and supported by slide, guide and fixed rigid supports were taken into account. Expansion joints in district heating pipelines are installed due to significant changes in their length caused by temperature changes. Subsoil deformations in mining areas cause displacements of supports and thus pipelines are subjected to additional displacements, forces and bending moments. Pipelines are protected against this impact by the use of additional expansion joints or expansion joints with an increased operating range. In the article, the way of assessing the possibility of transferring mining deformations of the subsoil by existing above-ground pipelines was presented. Evaluation of the possibility considers: a. the assessment of the technical condition of the pipelines and supports based on the conducted inventory in the field, b. the assessment of the current ability to transmit the subsoil deformations by expansion joints, c. the kinematic analysis of the pipelines, taking into account the extreme values of support displacements, resulting from predicted values of mining deformations of the subsoil, d. the static and strength analysis for selected elements or sections of the pipelines.