Joining Of Pipes Research Articles

Microwave joining of copper pipes using selective microwave hybrid heating process: Simulation and experimental study

High thermal conductivity of copper poses serious challenges in its joining in conventional welding techniques leading to development of alternate welding techniques. Microwave welding is one such newly developed joining technique that use selective microwave hybrid heating (SMHH). The joining of the copper pipes using SMHH has not been explored in existing literature. The present paper attempts the microwave joining of copper pipes using SMHH. The exposure time required for joining copper pipes using SMHH was predicted by COMSOL Multiphysics software. The joining was attempted at the predicted exposure time using a novel cavity design inside a conventional microwave oven. The copper pipes have been successfully joined at temperature and exposure period of 1080ºC and 720 s respectively and was in good agreement with the predicted values i.e., 708 s. Scanning electron microscopy (SEM) revealed good metallurgical bonding between the base metal and joint interface. The presence of columnar grains has been observed at heat affected zone (HAZ) using electron back scattered diffraction (EBSD). EBSD analysis revealed randomly arranged grains with mixed modes of planes inside the base metal. The occurrence of high angle grains (HAGs) along with high dislocation density in base metal resulted in the improvement in the mechanical properties as revealed in grain average misorientation (GAM) maps. The maximum value of microhardness has been observed at the joint region (105 ± 7 Hv) followed by base metal and HAZ i.e. (97 ± 5 Hv) and (89 ± 8 Hv) respectively owing to the existence of fine grain of copper (µm) and carbide formation.

Joining of EN AW 6060 Pipes by Plastic Forming

The article deals with an innovative, but not widely used type of joining of aluminum pipes through experiments. The joints are formed by plastic forming. The process is carried out in one step using the principle of pipe expansion, in order to bring the mating surfaces of the two pipes into a suitable position for the subsequent joining, which is created by means of plastic instability and simultaneous pressure flanging. Experimental tests were carried out with the tools designed to create most suitable joints. The length of the plastically formed pipe sections involved in the joint, the angle of the sharpened pipe ends, and the thickness of the formed joints were analyzed. One of the main goals of this study is to determine the proper joining parameters, such as tool distance or edge tapering for further investigations. As per the test results, it can be stated that the technology is suitable for joining aluminum tubes in a cost-effective way, and based on the promising strength results, further investigations will be conducted.

Friction-Assisted Dissimilar Solid State Lap Joining of Aluminum and Copper Pipes

Friction-Assisted Dissimilar Solid State Lap Joining of Aluminum and Copper Pipes

Investigating friction spin welding of thermoplastics in shear joint configuration

The welding of thermoplastic pipes under a shear joint configuration using friction spin welding is investigated. The shear joint configuration consists of two cylindrical and concentric polypropylene plastic parts joined with each other at their interfacing cylindrical surfaces through frictional heat generation. The effects of welding pressure and rotational velocity on the joint overlap distance and joint strength between the parts of polypropylene plastic are evaluated. The study is of a specific application in making plastic pressure vessels and joining of pipes. The joint strength is tested by conducting the hydraulic pressure burst test. The burst test is conducted for welded specimens manufactured using different values of rotational velocity and welding pressure. It is observed that at the constant spin velocities, the welding pressure in the range 64.8 to 65.2 kPa produced better joint strength than the other values of welding pressure in the overall range 64–76 kPa. It is concluded that the suitable welding pressure range to manufacture polypropylene plastic pressure vessels in the shear joint configuration using friction spin welding is 64.5 to 65.2 kPa. Further, it is established that the user can control the joint overlap distance at 64.8 kPa welding pressure by selectively controlling the rotational velocity in the range of 700 to 2500 rpm.

Challenges in joining of metallic pipes using microwave hybrid heating

Microwave hybrid heating (MHH) is a distinct and emerging alternative joining technique used to join metallic materials compared to available conventional joining processes such as FW, TIG, MIG, etc. MHH shows significant characteristics such as selective and volumetric heating, lower processing time, eco-friendly processing against conventional joining. This paper aims to investigate the joining of 316L stainless steel pipes by incorporating micrometric size (45μm) of 316L stainless steel powder in between the faying surfaces of the candidate material. Charcoal as a susceptor material was placed at the joint zone and exposed to microwave energy at 2.45 GHz inside the domestic microwave applicator at 900 W power levels. The challenges and principles involved in joining SS 316 L pipes using MHH have been discussed and initial experimental observations have been analyzed.

Influence of plunge depth during friction stir welding of aluminum pipes

This study focuses on the application of friction stir welding (FSW) process for joining of pipes. It addresses key issues associated with fusion welding techniques, such as lack of fusion, over penetration, slag inclusions, root crack, undercut root gap, and thermal distortion. The influence of process parameters on the physical properties during FSW of aluminum pipes has been studied, which allows selecting an optimum combination of parameters for achieving superior welds. Physical responses such as variation in axial force, torque, temperature, and power have been analyzed. Tensile test of the joints fabricated shows a maximum of ∼90% joint strength efficiency with respect to the base material. The peak temperature or heat input is found to be increasing during FSW, which creates a larger grain size in the stir zone of the joints, resulting in the higher hardness of the joints.

Double-Sided Welding as an Alternative for Joining Internally Clad Pipes

AbstractHigh strength steel pipes internally clad with nickel (Ni) superalloys are components widely used in the oil and gas industry in the production of rigid risers. The joining of clad pipes is...

Exploration of magnetically impelled arc butt welded SA210GrA tubes for boiler applications

Abstract Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of SA210GrA tubes were carried out to study the microstructure of weldedments. The effect of arc current on the weld interface is also detailed and is found to be defect free at higher values of arc currents. The results reveal that MIAB welded specimens shows superior structural property correlation for high pressure applications with an added benefit of improved productivity at lower cost. The study will enable the use of MIAB welding for high pressure applications in power and defence sectors.

Finite element analysis of a sandwich pipe joint

Sandwich pipes in which the core material performs both thermal insulation and structural function are viewed as a lightweight alternative to conventional pipe-in-pipe systems in which insulation material carries no loading. Developing a suitable method that permits the joining of sandwich pipes in an efficient manner is essential for their successful application. In this paper, the mechanical response of a swaged field joint between sandwich pipes subjected to bending is investigated using a series of finite element models. In order to gain a thorough understanding of the response of the joint components to installation based loadings, parametric studies are carried out to establish the effect of the inner pipe thickness, cutback length, and stiffness of the field joint filler on the strain concentration at the joint, with particular focus on the swaged weld region and the girth weld region. The influence of interface adhesion properties and weld metal yield strength on the variation of strain intensity is also evaluated. Numerical studies show that increasing filler stiffness and maintaining a cutback length less than 2.5 times the radius of the inner pipe could produce lower strain intensity at the two regions of interest.

Experimental- and numerical-based studies for magnetically impelled arc butt welding of T11 chromium alloy tubes

Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. Past studies based on experiments and finite element analysis (FEA) suggested that the weld quality can be significantly improved by proper adjustment of its input parameters such as current, voltage, flux density, etc. Experiments are useful for understanding the physics behind the process, but the quantification and optimization of the MIAB process needs a thorough numerical investigation. Therefore, the present work presents a combined experimental and numerical study for investigating the arc speed indicator of the T11 grade chromium alloy tubes of the MIAB process. Firstly, experiments on the MIAB process are conducted, and the arc speed is measured based on the four inputs (welding current, welding voltage, magnetic coil current, and voltage). This is followed by introduction of a numerical approach of multi-gene genetic programming (MGGP) to formulate a functional relationship between arc speed and the four design variables. The statistical error metrics based on the square of correlation coefficient, relative error (%), and root mean square were used to validate the model performance against the experimental data. The proposed model can be utilized to select the best combination of input variables to optimize the arc speed, which has a vital role in governing the weld quality. In addition, 2-D analysis conducted reveals that the welding current influence the arc speed of the clay the most followed by coil current and coil voltage.

Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

Abstract Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11) tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ). To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations of arc current and arc rotation time. It is found that TMAZ shows higher hardness than that in base metal and displays higher weld tensile strength and ductility due to bainitic transformation. The effect of arc current on the weld interface is also detailed and is found to be defect free at higher values of arc currents. The results reveal that MIAB welded samples exhibits good structural property correlation for high pressure applications with an added benefit of enhanced productivity at lower cost. The study will enable the use of MIAB welding for high pressure applications in power and defence sectors.

Evaluation of a Pipe-Flange Connection Replacing Fusion Welding

Joining of steel pipes and pipe flanges use today the conventional method of fusion welding, where the flange is girth-welded onto the pipe. However, fusion welding of flanges to pipes is associated with many disadvantages such as the final quality of the weld, degradation of the mechanical properties of the base pipe near the heat affected zone, defects and cracks appearing in the weld, misalignments, to mention a few.The current study proposes a novel pipe-flange connection to replace the fusion welding process of steel pipes with a method based on cold working. The method is based on that the steel pipe is inserted into the neck of the flange, in which two circumferential grooves are manufactured. An expansion tool having two teeth is entered from the open side of the connection and is expanded hydraulically such that the teeth deform the pipe and cold work it plastically into the grooves. This will provide a strong joint between the flange and pipe. In this study the performance of the connection is maximized by optimizing the design of the flange and the expansion tool.

Neutron diffraction investigations of residual stresses in titanium–steel and niobium–steel bilayer pipes manufactured by explosive welding

Joining of pipes made of stainless steel (SS) and some other metals (Ti and Nb) still represents a serious technical problem. Recently reliable and hermetic joining of pipes from SS and Ti/Nb has been achieved by the explosive bonding technique at the Russian Federal Nuclear Center (Sarov). These adapters are supposed to be used at the future International Linear Collider with crossed electron-positron beams. The adapters have shown excellent behavior at room and liquid helium temperatures, during high pressure tests and thermal cycling. Here we describe the neutron diffraction experiments, in which the residual stresses in the SS-Ti and SS-Nb adapters were measured with the POLDI instrument at the SINQ spallation neutron source.

Dynamic Interaction between Manipulator and Omni-Directional Platform

Recent advancements in mechatronics has led to tremendous development of application of robots for industrial applications involving high health hazards, rough working conditions and difficult to reach locations. Robot assisted welding is one such high risk operation for human being. The industrial arc welding robots are either mounted on the floor, table or on overhead rails. In this scenario, the jobs to be welded are brought to shop floor. However, the on-sight joining of big pipes and structures with precision and speed, demands for mobility of welding robot. In this research work, a novel concept of mounting 5-dof welding robot on the omni-directional platform (Omni-WMR) is implemented to provides immense maneuvering mobility to the manipulator. This paper presents the combined dynamic model of omnidirectional mobile robot for welding operation to study the effect of dynamic interaction between manipulator and mobile platform. Dynamic interaction is carried out to find the variation in torque at manipulator link due to the motion of platform as well as its location on the platform. In addition, the variation in torque developed at platform wheels due to positioning the manipulator at two different locations on platform is accessed. For this, two case studies have been discussed to study the effect of dynamic interaction between manipulator and omni-directional platform.

Residual stresses in a stainless steel – titanium alloy joint made with the explosive technique

Joining of pipes from stainless steel (SS) and titanium (Ti) alloy still experience serious technical problems. Recently, reliable and hermetic joining of SS and Ti pipes has been achieved with the explosive bonding technique in the Russian Federal Nuclear Center. Such adapters are earmarked for use at the future International Linear Collider. The manufactured SS-Ti adapters have excellent mechanical behavior at room and liquid nitrogen temperatures, during high-pressure tests and thermal cycling. We here report the first neutron diffraction investigation of the residual stresses in a SS-Ti adapter on the POLDI instrument at the SINQ spallation source. The strain scanning across the adapter walls into the SS-SS and SS-Ti pipes sections encompassed measurement of the axial, radial and hoop strain components, which were transformed into residual stresses. The full stress information was successfully determined for the three steel pipes involved in the joint. The residual stresses do not exceed 300 MPa in magnitude. All stress components have tensile values close to the adapter internal surface, whilst they are compressive close to the outer surface. The strong incoherent and weak coherent neutron scattering cross-sections of Ti did not allow for the reliable determination of stresses inside the titanic pipe.

Analysis of pressure exertion’s effect on electrofusion welding process of polymer pipes

Electrofusion welding process is perhaps the most common method in joining of polymer pipes at time of installation. To provide a sturdy, ideal weld, certain parameters have to be accounted for in precise measure. One such item is applied pressure while process takes place. By conducting several experiments from welding to testing in joining of polymer pipes, required data was gathered from analysis of parameters mentioned. In particular, effect of pressure exertion, its quantity and duration was contemplated. Moreover, impact analysis of applied pressure as an effective parameter on welding of polymeric pipes has been investigated. This pressure is exerted to provide internal contact between melting surfaces and to prevent molten material escape from welding zone during expansion phase. In this study, optimized pressure of weld has been sought, measured, and recognized to provide high-strength weld. Shear strength at initial pressure and as its function, change in thickness of connection line, and displacement change were all measured through experimental methods designed and were utilized for this purpose. Tensile test was conducted to measure the amount of strength of the weld in pipes. The findings were indicative of optimized values of exerted pressure.

Defoe’s Writings and Manliness: Contrary Men by Stephen H. Gregg

225 to get published. Ms. Maruca rightly states that the statute of 1709, known as the ‘‘Copyright Act,’’ was more of a smokescreen protecting booksellers’ copyright interests than it was a law intended to establish authors’ copyrights. However, her follow-up statement—‘‘in order to get published a writer had to sell this right’’—is not entirely true. Many publications of the following decades show imprints that read ‘‘Printed for the Author by [such and such a printer].’’ In such cases, of course, the author did not sell the copyright to the printer (or bookseller), but rather assumed all expenses the publishing agent incurred for the book’s paper, printing, and advertising . Likewise, authors who had already established popular reputations and therefore considered their new publications to be sure sellers did not feel compelled to sell their copyrights to their booksellers; and often booksellers, especially beginners, were happy just to share the profits with such authors. Finally, as Ms. Maruca herself notes, Pope set up businesses for a series of booksellers (Lawton Gilliver, Dodsley) so that he would not have to negotiate with established City booksellers for the copyrights to his works. Notwithstanding Ms. Maruca’s significant achievement, at times certain themes seem questionable or disproportionate, for example, her penchant for sexualizing the printing/publishing process: she dedicates thirteen pages, in one instance, to a sexual interpretation of Moxon’s and Smith’s typesetting equipment. Although indeed Moxon employed the terms ‘‘male’’ and ‘‘female’’ in describing the interaction of the tools of his trade, his allusions were more likely voiced in the jargon of a modern plumber’s describing the joining of pipes. Ms. Maruca’s novel and intriguing interpretation takes historical liberties. Finally, traditional book historians will find her volume hard travelling. Whereas traditional book history has usually been conveyed in the simple language of the trade, the new language of media theory that characterizes Ms. Maruca’s treatment often obscures the subject she is attempting to encapsulate. We find such long stretches as: ‘‘Such an analysis does acknowledge the especially slippery nature of print as a self-advertising discourse, invisibly mediating itself through itself. To disrupt its tautology and to re-envision it as the graphic, visible tool that it is, we must turn to the rhetoric of print, to print as a human-linguistic construct.’’ It is not surprising that the author misinterprets Thomas Sprat’s intention when the seventeenth-century bishop, attempting to put an end to the inflated language that had characterized science of the past, insisted that the work of the Royal Society be carried on in the ‘‘language of Artizans, Countrymen, and Merchants.’’ James E. Tierney University of Missouri–St. Louis BOOKS BRIEFLY NOTED STEPHEN H. GREGG. Defoe’s Writings and Manliness: Contrary Men. Burlington , VT: Ashgate, 2009. Pp. 208. $99.95. Defoe’s women—Moll Flanders and Roxana—have gender issues. Until recently , his men did not. Robinson Crusoe struggled for control over his passions , H. F. the Saddler wrestled with a vengeful (if not absent) God who visited 226 London in the time of the plague, Colonel Jack looked for gentility in all the wrong places, and Captain Bob dared not explain the basis of his friendship for William the Quaker, but none of these dilemmas was thought to be related to their masculinity. Mr. Gregg now shows us that a unifying theme of much of Defoe’s writing had to do with the nature of manliness, a problem made especially urgent by the emergence of a culture in which such traditionally (or stereotypically) feminine practices as the pursuit of civic and religious virtue, the consumption of luxury goods, and a dependence on credit and trade increasingly defined what it was to be a man. Defoe, like the Earl of Shaftesbury and other contemporaries, assumed that masculinity was normative and natural, and defined femininity (and feminized men, like fops) as the contradiction to manliness. Thus physical vigor, personal courage, rationality, godliness, selfcontrol , and an ethic of civic utility comprised manliness, and their contraries were feminine. But none of the males in Defoe’s writings exhibited all of these qualities all of the time; rather, his men are often anxious that they...

Fast joining of composite pipes using UV curing FRP composites

AbstractIn this paper, twelve butt‐weld composite pipe joints were prepared. Among them, six were prepared using ultraviolet (UV) curing fiber reinforced plastics (FRPs) and six were prepared using ambient environment curing FRPs as controls. Filament wound composite pipes were used. Each section of pipe was 304.8 mm long with a 101.6 mm inner diameter. The wet lay‐up technique was used to prepare the test samples. The curing time for the UV curing samples was 40 minutes, while the curing time was 24 hours for the control samples. Both internal pressure tests and four‐point bending tests were conducted on the prepared samples. The test results show that the UV curing FRP wrapped composite pipe joints achieved nearly the same bending strength as the control samples. However, the internal pressure rating achieved by the UV curing FRP coupled joints was lower than that achieved by the control samples. A finite element analysis was conducted to understand the mechanism for the lowered internal pressure rating. Based on the test and the finite element analysis results, the UV curing FRP can be used in joining composite truss structures and composite frame structures. Suggestions were made to increase the internal pressure rating of UV curing FRP coupled composite pipes. Polym. Compos. 25:298–306, 2004. © 2004 Society of Plastics Engineers.

Characterization of Fe–Mn–Si–Cr shape memory alloys containing VN precipitates

Abstract An Fe–28Mn–6Si–5Cr shape memory alloy containing VN coherent precipitates has been developed so that mechanical properties and shape recovery are high enough to be applied to pipe joining of steel pipes. The proof stress over 400 MPa and 3.4% of recovery strain are obtained on aging, where VN compounds are formed homogeneously in the parent Fe–28Mn–6Si–5Cr material. Electron microscopic observation has indicated that high-density formation of coherent VN precipitates can enhance the proof stress of the alloy. A large amount of shape recovery strain has been obtained from the shape memory alloy containing high densities of VN compounds that exhibit large size.

Effects of Over-Torque on Stress Relief in Conical Threaded Connections

The analysis of the stress state induced by the make-up torque of tapered threaded connections is very important for the improvement of both the static and the fatigue resistance of such connections. Make-up torque induces a nonuniform stress state; in the same way, the axial load induced by the make-up torque is distributed in a nonuniform way along the sections of the coupled elements of the connections. The most important consequence is the overloading at the first threads engaged, which has to be summed to the stress concentration in the core section due to the notch effect. The aim of this paper is to analyze the stress and strain fields induced by make-up torque in tapered threaded connections; in particular, the purpose is to investigate the effects of the application of over-torque before putting the connections into service (stress relief due to over-torque before nominal make-up torque application). The evaluation of the local stress state and of stress relief, with a good level of precision, was performed by using finite element models in order to assess the percentage of load carried by each thread after the application of the make-up torque and further axial tensile or compressive loads. Numerical results confirmed the favorable thread load distribution induced by overloading. Experimental tests carried out on full-scale connections, used in the oil and gas industry for the joining of pipes, confirmed the numerical results.