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Showing papers on "Electric resistance welding published in 2020"


Journal ArticleDOI
01 Mar 2020
TL;DR: The present work provides an overview of interdisciplinary challenges occurring at joints which are exposed to electrical current with a strong focus on interconnecting batteries for electric cars.
Abstract: Automotive battery packs used for electromobility applications consist of a large number of individual battery cells that are interconnected. Interconnection of the battery cells creates an electrical and mechanical connection, which can be realised by means of different joining technologies. The adaption of different joining technologies greatly influences the central characteristics of the battery pack in terms of battery performance, capacity and lifetime. Selection of a suitable joining technology, therefore, involves several considerations regarding electrical and mechanical properties and an assessment of production and operational conditions. Particularly, during the operation of an electric vehicle, challenges and mutual dependencies of the electrical and mechanical system emerge. The present work provides an overview of interdisciplinary challenges occurring at joints which are exposed to electrical current with a strong focus on interconnecting batteries for electric cars. It summarizes common quality criteria for the joining technologies and recombines those with criteria deduced from an electrical engineering point of view. Scientific literature concerning different joining technologies in the field of battery manufacturing is discussed based on those criteria. The most common joining techniques are ultrasonic welding, wire bonding, force fitting, soldering, laser beam welding, and resistance welding. Besides those, friction stir welding, tungsten inert gas welding, joining by forming and adhesive bonding are presented.

91 citations


Journal ArticleDOI
TL;DR: In this article, a fiber coupled 500-W blue laser system coupled to a welding head was used for keyhole welding in copper, stainless steel, and aluminum, achieving an average power density of 1.6 MW/cm2.
Abstract: Welding copper to itself and other metals is challenging using conventional welding techniques. The process window for welding copper with an infrared (IR) laser, resistance welder, or an ultrasonic welder is very narrow. In the case of the infrared laser, the high reflectivity at these wavelengths makes it difficult to couple the power into the material and control the temperature of the weld puddle. In the case of ultrasonic and resistive welding, the high thermal conductivity of the material and the tendency to create particles cause less than ideal welds. These fundamental problems can be overcome by using a laser with a wavelength that is highly absorbed by these materials. This paper will present recent welding results using a fiber coupled 500-W blue laser system coupled to a welding head to deliver a 215 μm spot size and an average power density of 1.6 MW/cm2. These results will be compared with the authors’ previous results from a free space delivered laser system that was the prototype for the 500-W fiber coupled laser. The fiber coupled laser system performance exceeded the free space performance because of two factors: (1) the welding was able to be performed at normal incidence (90°) to the surface allowing for greater power coupling into the copper and (2) a smaller spot size with a higher power density was used (1.6 MW/cm2 vs 398 kW/cm2). Tests on welding battery components, including stacks of foils, buss bars, hairpins (for motors), and other components, with no porosity and no spatter will be covered. Both copper and mixed metals welding results will be presented. Tests have also been performed with 1 kW of laser power from a processing head with a 400 μm spot size and an average power density of 800 kW/cm2. Both systems have enough power density to initiate the keyhole welding process in copper, stainless steel, and aluminum. The difference in welding speeds for these two systems will be compared in this paper.

30 citations


Journal ArticleDOI
TL;DR: In this article, a literature review on the joining methods applicable to thermoplastic based composites and their potential applications to be used as repair procedures in structural elements is presented, focusing on the three most promising fusion bonding techniques: resistance welding, induction welding, and ultrasonic welding.
Abstract: Thermoset fiber reinforced composites, widely used in current structural applications, have complex repair procedures and generates significant amounts of scrap due to its recycling difficulties, which does not comply with the most recent environmental restrictions. These disadvantages may be overcome by using a thermoplastic matrix phase, which is very suitable to be joined and repaired by local melting, making the composite material fully recyclable. This work presents a literature review on the joining methods applicable to thermoplastic based composites and their potential applications to be used as repair procedures in structural elements. The effectiveness of selected adhesive and fusion bonding techniques for several thermoplastic composite systems is evaluated by a comparative study based on the joints’ strength and toughness results available in the literature. This work focuses on the three most promising fusion bonding techniques: Resistance welding, induction welding, and ultrasonic welding. The advantages and drawbacks for each one of these processes are discussed, as well as their suitability for several specific structural applications. In addition, several discordant aspects for each welding technique are identified and the corresponding recommendations are discussed. A compilation of analytical models for the mechanisms of heat generation and transient heat transfer modelling is also presented for each fusion bonding process in order to promote their application in numerical modelling.

29 citations


Journal ArticleDOI
TL;DR: In this paper, surface coatings are applied on a stainless-steel (SS) mesh to improve the adhesion between a thermoplastic matrix, i.e., polyphenylene sulfide (PPS), and the SS mesh heating element.
Abstract: Resistance welding of thermoplastic composites involves applying an electric current to a heating element, usually a stainless-steel (SS) mesh, which heats up by Joule effect, melts the surrounding polymer matrix and remains at the joint interface following the welding operation. In this study, the adhesion between a thermoplastic matrix, i.e., polyphenylene sulfide (PPS), and the SS mesh heating element is evaluated and improved through the application of surface coatings on the SS. The coatings are based on an organosilane, a bivalent molecule often used to create an organic coating on metals. The efficiency of the surface coatings is evaluated by measurement of the water contact angle on treated SS plates, characterization of the coating by ATR-FTIR, observations by SEM and TEM and mechanical testing of resistance-welded quasi-isotropic carbon fibre (CF)/PPS joints. A lap shear strength (LSS) improvement of 32% is reported for joints welded using the treated heating elements relative to joints welded using untreated heating elements. Double cantilever beam tests between a SS plate and the CF/PPS composite also show a much better adhesion between the PPS and SS following surface coating, with a higher load at failure and fracture surfaces showing polymer and fibre remaining attached to the SS plate.

24 citations


Journal ArticleDOI
TL;DR: In this paper, two different types of weld inserts were embedded in glass fiber reinforced polypropylene sheets and then welded to steel sheets, and the quality of the joints was analyzed by microsections before and after the welding process.
Abstract: Joining is a key enabler for a successful application of thermoplastic composites (TPC) in future multi-material systems. To use joining technologies, such as resistance welding for composite-metal joints, auxiliary joining elements (weld inserts) can be integrated into the composite and used as an interface. The authors pursue the approach of embedding metal weld inserts in TPC during compression moulding without fibre damage. The technology is based on the concept of moulding holes by a pin and simultaneously placing the weld insert in the moulded hole. Subsequently, the composite component can be joined with metal structures using conventional spot welding guns. For this purpose, two different types of weld inserts were embedded in glass fibre reinforced polypropylene sheets and then welded to steel sheets. A simulation of the welding process determined suitable welding parameters. The quality of the joints was analysed by microsections before and after the welding process. In addition, the joint strength was evaluated by chisel tests as well as single-lap shear tests for the different weld insert designs. It could be shown that high-quality joints can be achieved by using the innovative technology and that the load-bearing capacity is significantly influenced by the weld inserts head design.

21 citations


Journal ArticleDOI
TL;DR: In this paper, three compatible thermoplastic polymers poly(methyl methacrylate) (PMMA), amorphous polyamide (PA12TR90), and poly(hydroxy ether) (phenoxy) were chosen to determine their affinity and interphase formation with the epoxy system.
Abstract: This study focuses on investigating thermoplastic polymers and their interphase behaviour with the fast-curing epoxy system Araldite LY3585/Aradur 3475. The three compatible thermoplastic polymers poly(methyl methacrylate) (PMMA), amorphous polyamide (PA12TR90), and poly(hydroxy ether) (phenoxy) were chosen to determine their affinity and interphase formation with the epoxy system. The final concept involves the use of a thermoplastic as a boundary layer on top of the epoxy to establish a connection between two joined parts by resistance welding. The thermoplastic boundary layer was generated by co-curing during the curing process. The experiments resulted in a high compatibility between phenoxy and PMMA in the selected epoxy system which leads to excellent mechanical properties after welding. Phenoxy showed the strongest joints, with an average lap shear strength of 25 MPa, demonstrating the high potential of this joining technique for industrial applications in the automotive and wind energy fields.

18 citations


Journal ArticleDOI
20 Feb 2020
TL;DR: A critical review of the current state of the art of welding molybdenum alloys components is presented in this paper, where the advantages and disadvantages of various methods, i.e., electron-beam welding (EBW), tungsten-arc inert gas (TIG) welding, laser welding (LW), electric resistance welding (ERW), and brazing and friction welding (FW) are discussed with a view to imagine future directions.
Abstract: Owing to its potential application prospect in novel accident tolerant fuel, molybdenum alloys and their welding technologies have gained great importance in recent years. The challenges of welding molybdenum alloys come from two aspects: one is related to its powder metallurgy manufacturing process, and the other is its inherent characteristics of refractory metal. The welding of powder metallurgy materials has been associated with issues such as porosity, contamination, and inclusions, at levels which tend to degrade the service performances of a welded joint. Refractory metals usually present poor weldability due to embrittlement of the fusion zone as a result of impurities segregation and the grain coarsening in the heat-affected zone. A critical review of the current state of the art of welding Mo alloys components is presented. The advantages and disadvantages of the various methods, i.e., electron-beam welding (EBW), tungsten-arc inert gas (TIG) welding, laser welding (LW), electric resistance welding (ERW), and brazing and friction welding (FW) in joining Mo and Mo alloys, are discussed with a view to imagine future directions. This review suggests that more attention should be paid to high energy density laser welding and the mechanism and technology of welding Mo alloys under hyperbaric environment.

17 citations


Journal ArticleDOI
TL;DR: In this paper, a carbon nanotube (CNT) reinforced laminae was embedded into the interface of the welding region to enhance the strength of the hybrid joints of Ti -GF/PEI.

15 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of superimposed ultrasonic vibration on resistance spot welding (RSW) of aluminum alloy AA6061-T6 were investigated, and ultrasonic resistance welding (URW) was applied to weld AA 6061 at various conditions and compared with the results from RSW.

15 citations


Journal ArticleDOI
TL;DR: In this article, wire mesh interlayers are introduced to fabricate high interface strength metal-polymer-metal sandwich panels, where resistance welding is used to join metal sheets to wire mesh at predesignated spots, and vacuum hot pressing is employed to infuse polymer into the wire mesh.

15 citations


Journal ArticleDOI
TL;DR: The Multi-Spot-Joint as discussed by the authors is an innovative joining concept bypassing the problems of conventional joining techniques by using small-scale form-fitting elements in combination with established resistance welding processes.

Journal ArticleDOI
TL;DR: In this article, the effect of mechanical properties like Hardness, Tensile strength along with Microstructure by varying the tool rotational speed of 500 rpm, 710''rpm, 1000''rpm and 1400''rpm during the friction stir welding of Aluminium Alloy 6082 with different reinforcement percentages of 5%, 10% and 15% of Al2O3.

Journal ArticleDOI
TL;DR: In this article, a two-stage projection welding process with an additional insert element was proposed to join aluminum-silicon-coated hot stamped ultra-high strength steel with aluminum.

Journal ArticleDOI
TL;DR: In this article, an electric resistance welding method was used to construct steel pipe with diameters of 244 and 508 mm using two different optimized conditions (i.e., FMT and coiling temperature) to analyze the change in mechanical properties induced by the work-hardening effect during the piping process.
Abstract: Oil country tubular goods (OCTG) steels with a low yield ratio (yield strength/tensile strength) and excellent impact toughness have recently been demanded to ensure mining performance and safety. From this viewpoint, the optimization of the manufacturing conditions is important because they influence the microstructure and mechanical properties of the steels; in particular, in the case of OCTG steels with carbon contents greater than 0.2 wt%, the finishing mill temperature (FMT) and coiling temperature (CT) strongly affect the microstructure of the final products, which are generally composed of ferrite and pearlite phases. In this study, 0.39C-0.23Si-1.56Mn-0.11Cr steel plates were fabricated under various FMT and CT conditions and their yield strength, tensile strength, and impact energy were investigated. In addition, pipes with diameters of 244 and 508 mm were manufactured via an electric resistance welding method using two of these strips fabricated under two different optimized conditions [(1) FMT = 880 °C and CT = 630 °C and (2) FMT = 800 °C and CT = 690 °C] to analyze the change in mechanical properties induced by the work-hardening effect during the piping process. The results revealed that the FMT and CT are closely related to the volume fraction of the ferrite phase, the grain size and lamellar spacing of the pearlite phase, and the tensile and impact properties of the steel strips; the variations in the microstructure and mechanical properties with the FMT and CT were also discussed in detail.

Journal ArticleDOI
TL;DR: In this article, a composite ceramic-centered annular electrode (RAW) was adopted to increase the strength of welded joints by the formation of a large nugget with low indentation depth.

Journal ArticleDOI
TL;DR: In this paper, the authors present the results of failure analysis carried out on leaking of pipes and fittings and give recommendation on good fabrication practices to be followed so that similar kind of failures could be avoided in future.

Journal ArticleDOI
TL;DR: In this article, the impact of defects on similar sheets and dissimilar sheets used in the automotive industry was investigated by using finite element method for non-destructive tests on spot welding, which is one of the types of resistance welding used in this experiment for sheet welding.
Abstract: This paper investigates the impact of defects on similar sheets and dissimilar sheets used in the automotive industry. Spot welding is one of the types of resistance welding used in this experiment for sheet welding. The thickness of sheets welded by the spot welding method can be between 0.5 and 3 mm. In this paper, the simulation is performed by finite element method for non-destructive tests on spot welding. This study investigated the propagation of ultrasonic waves in two similar layers of stainless steel and galvanized stainless steel sheets and two dissimilar layers of stainless steel sheets and galvanized stainless steel sheets in different thicknesses. This test was performed by ultrasonic immersion method and the intensity and amplitude of the reaction of the resulting defect waves and its effect on the results were also investigated. Due to the performance of finite element method softwares, Comsol Multiphysics software because of its high accuracy used. It has been studied various factors and conditions including excitation frequency, boundary conditions, the most suitable position for the probr Fto stimulate the waves, focused or unfocused waves in the simulation, sensitivity analysis of mesh size and appropriate mesh size for simulation. In this paper, the joint of similar sheets and dissimilar sheets is investigated. For this performance, the average relative error that can meet the industrial requirement is mentioned. The results of the simulation with the results of the experimental test They were compared and investigated And with the amount of error tests, have acceptable results and it can be used with the error specified and can meet the needs of the automotive industry.

Journal ArticleDOI
TL;DR: In this paper, a procedure has been brought out to understand the relationship between processing conditions and performance of the fiber reinforced thermoplastics (FRTP welding joints), where continuous glass fiber reinforced polypropylene (GF/PP) laminates fabricated by hot-pressing method were investigated.

Journal ArticleDOI
TL;DR: In this article, an analysis of the influence of surface layers on the welding process was performed on aluminum-silicon and zinc-coated parts with temperature histories, typical for industrially manufactured partially hot-stamped parts with aluminum and zinc coating.
Abstract: One of the methods to achieve local change in material properties when producing high strength parts with tailored mechanical properties is variating temperature histories in the furnace prior to hot stamping. This causes changes in surface layer development of coated steels and thus differences in contact resistances, which determine heat development during the resistance welding process. To get a deeper understanding of the influences, surface layers have on the welding process, parts with temperature histories, typical for industrially manufactured partially hot-stamped parts with aluminum-silicon and zinc coatings were investigated. Static contact resistance was determined; measurements of dynamic resistances in welding process were conducted. Welding current ranges were determined for different heat-treated conditions. No correlation between static contact resistance and welding current range was found; however for Zn coating, the welding current range was moved towards lower welding currents and shrinked for the measured total static contact resistance of about 4000 μΩ. For aluminum-silicon coating, no dependence between welding current range and static contact resistance was evident. For Al-Si-coated steel, a novel criterion, based on the fraction of the resistive phases in the surface layer, determined by metallographic investigations was developed, allowing to determine material joinability.

Journal ArticleDOI
R. Goyal1, Mohamad El-Zein1
01 Mar 2020
TL;DR: In this article, the C-shape laser weld has been selected as the geometric shape in comparison to the straight linear shape of laser weld produced on a series of single lap joints.
Abstract: Traditional manufacturing processes, like arc welding and resistance spot welding, are still the main welding processes to join structural components used across the on/off-road vehicle industry. Due to the abundance of data, experiences and insights over the decades of usage, lot of fatigue design data has been generated for different joint geometries produced using these methods. The laser welding process has excellent capabilities to join thin sheet metal structures with minimum heat input resulting into lower deformation and improved productivity that offers significant benefit as compared to the arc and resistance welding processes. However, due to the agility of designing joint configurations and limited availability of understanding regarding the fatigue behaviour of laser welded joints, the need arises for the fatigue design data. Most of the research presents the use of straight linear shape laser welds and limited knowledge exist regarding the influence of shape of laser welds on mechanical and fatigue performance of the laser welded joints. The laser welded joints produce small notch like radius at the root of laser weld which could act as a stress raiser causing early crack initiation. For this work, C-shape laser weld has been selected as the geometric shape in comparison to the straight linear shape of laser weld produced on a series of single lap joints. Detailed fatigue experimental investigation has been carried out for linear and C-shape laser welded joints tested in 3 different orientations with respect to the applied cyclic load and several different R-ratio's and the results are compared. The metallurgical studies have been carried out to understand the failure mode and micro-hardness variations across the weld and heat affected zone. Further, the residual stress profiles have been compared for the C-shape laser weld with the linear welds using detailed X - Ray Diffraction based residual stress measurement.

Journal ArticleDOI
TL;DR: In this paper, the effects of freeze/thaw cycles on the mechanical performance and failure mode of resistance-welded carbon fiber/polyphenylene sulphide composite joints were evaluated.
Abstract: This study evaluates the effects of freeze/thaw cycles on the mechanical performance and failure mode of resistance-welded carbon fibre/polyphenylene sulphide composite joints Dry and moisture-sat

Journal ArticleDOI
11 Dec 2020-Polymers
TL;DR: The findings show that the quality of heating is determined by the shape and size of the electrodes, and parts based on woven fabric can be heated more homogeneously because of the existence of intersections between rovings, generating contact between fibers.
Abstract: Although direct Joule heating is a known technique for heating carbon fiber reinforced plastics, it is a yet unexplored heating method for thermoplastic prepregs before back-injection molding. The knowledge obtained from resistance welding, for example, is not directly transferable because of considerably higher heated volumes and more complex shapes. In this study, the governing parameters and process limits are established for this method. The influences of the contacting, the materials used, and the size of the heated part are investigated with respect to the part temperature and heating efficiency. The findings show that the quality of heating is determined by the shape and size of the electrodes. Larger electrodes lead to a more homogeneous temperature distribution. Parts based on woven fabric can be heated more homogeneously because of the existence of intersections between rovings, generating contact between fibers. An increase in part width results in uneven heating behavior.

Journal ArticleDOI
TL;DR: In this article, a Gleeble® thermo-mechanical simulator combined with microstructure characterization using a field emission scanning electron microscope was used to provide insights into seam weld formation during resistance welding (RW).
Abstract: A Gleeble® thermo-mechanical simulator combined with microstructure characterization using a field emission scanning electron microscope was used to provide insights into the seam weld formation during resistance welding (RW). Gleeble® was used to physically/microstructurally simulate the seam weld formation during RW for the first time. It was found that a peak temperature of 1500 ̊C and 10-mm stroke produced a microstructure in the solid-state bondline, the flash, and the heat-affected zone similar to the resistance welded pipe manufactured in an industrial scale. Using the force response obtained during seam weld formation in Gleeble®, microstructure characterization of the seam weld, and thermodynamic calculations, it is proposed the seam weld in a resistance weld consists of a mushy zone with delta ferrite and solute-enriched liquid, which solidifies into austenite, and on post welding cooling, transforms into ferrite and stringers of M/A, respectively. The presence of a mushy zone in the weld joints provides a physical explanation for the “decarburization” phenomenon observed in the seam of resistance welds.

Journal ArticleDOI
TL;DR: In this paper, an electrospark deposition AA4043 interlayer is applied for the dissimilar resistance spot welding of an aluminum alloy (AA5052) to a galvanized dual phase steel (GI DP600).
Abstract: The transportation industry is facing increasing pressure to lightweight vehicles and improve fuel economy. One option is the use of low-density aluminum alloys rather than steels. However, adoption of aluminum alloys is hampered by challenges during the welding of aluminum to steel. Here, an electrospark deposition AA4043 interlayer is applied for the dissimilar resistance spot welding of an aluminum alloy (AA5052) to a galvanized dual phase steel (GI DP600). A minimum 30% tensile lap-shear strength increase is obtained using this interlayer. This manufacturing technique has the potential to allow for greater adoption of aluminum alloys in vehicle lightweighting applications.

Book ChapterDOI
01 Jan 2020
TL;DR: This paper presents the use of analytic hierarchy process (AHP) and modified AHP to justify the selection of suitable welding technique for welded tube manufacturing.
Abstract: Traditionally, some of the alternative processes for manufacturing welded tubes have been high-frequency (HF) alternating current resistance welding and tungsten inert gas (TIG) welding. Recently, the laser welding (LW) is also emerging as a potential process owing to reduction in its cost. The HF electric resistance welding gained wider popularity and is almost always used without any second thoughts for manufacturing aluminum tube industry. A scientific examination of the decision criteria may make a way for systematic consideration and justification of newer technological developments to reap competitive advantages. This paper presents the use of analytic hierarchy process (AHP) and modified AHP to justify the selection of suitable welding technique for welded tube manufacturing.

Proceedings ArticleDOI
05 Oct 2020
TL;DR: In this paper, a split-pi converter is presented for resistance welding application, and the operation of the converter topology is validated with simulated results. But the utilization of hybrid energy storage such as battery-supercapacitor combination in the resistance welding applications can make a negative effect on the current pulse shaper circuit.
Abstract: In this paper, a Split-pi converter is presented for resistance welding application. Generally, the resistance welding application requires high current and low voltage circuits with high operating frequency as a current pulse shaper. The recently invented Split-pi converter has great potential in the power electronics field due to its ability to work in different switching modes during operation. The utilization of hybrid energy storage such as battery-supercapacitor combination in the resistance welding application can make a negative effect on the current pulse shaper circuit. To overcome this effect, a Split-pi converter is presented in this work. The operation of the converter topology is validated with simulated results.

Journal ArticleDOI
TL;DR: In this article, a new dimensionless welding quality criterion that takes into account the unbalances of metal flow is proposed, based on analysis of simulation results obtained by QForm Extrusion FEM software and experiments.

Journal ArticleDOI
TL;DR: In this paper, a numerical model of the ideal weld is presented, which enables the elimination of all welding imperfections, including, among other things, an indent left by the electrode as well as stresses and deformations of materials present in the actual welded joint.
Abstract: The paper presents investigation on the ideal spot weld numerical model. The weld discussed in the paper was made by the resistance spot welding of two overlapping steel sheets. The ideal weld contained three parts, i.e. two welded steel sheets and an intermediate component (connector) made of the same material. The connector was placed between the sheets, assembled mechanically and fixed. A numerical model of the ideal weld enables the elimination of all welding imperfections, including, among other things, an indent left by the electrode as well as stresses and deformations of materials present in the actual welded joint. The ideal weld was intentionally not subjected to the thermal cycle. As a result, the heat-affected zone and the molten nugget were eliminated from the model (welding area). Consequently, the entire tested (analysed) weld specimen only had the properties of the base material. The analysis presented in the paper is based on 3D FEM numerical modelling and experimental validation. The numerical model of the ideal weld (nugget surface) was investigated in relation to various shapes of the nugget (e.g. circular, square and rectangular) as well as in relation to different dimensions. The research also involved the performance of a comparative analysis including various welding conditions. The analysis was carried out to determine the highest possible value of shear force generated during a static tensile test. The results of the numerical tests were compared with the results of selected laboratory tests.

Journal ArticleDOI
TL;DR: In this article, the authors describe the welding process study with the subsequent control of cooling for full-profile rail joints, produced by passing alternating electric current pulses after welding, and investigate the welding mode influence on the welded joint quality.
Abstract: The article describes the welding process study with the subsequent control of cooling for full-profile rail joints, produced by passing alternating electric current pulses after welding. The welding mode influence on the welded joint quality was investigated. Welding was carried out on a resistance butt welding machine MCP-6301 in conditions of the rail welding company OOO RSP-M (RSP-29). For research, the samples of P65 type full-profile rails of DT350 category 600 mm long were cut out. The isothermal holding conditions after welding were controlled using a personal computer with a change in the program of the SIMATIC S7-300 industrial controller and the software SIMATIC STEP 7, which allows modes of controlled cooling to be set. The control program was written in the LAD graphic language. To search for optimal modes of controlled cooling, a complete factor experiment N = 2k was carried out. Non-heat-treated joints were tested for three-point static bending according to the state standard STO RZD 1.08.002 – 2009 “Railway rails, welded by electric contact method”. Static bending tests were carried out on the press of PMS-320 type. Values of the force arising during bending Pbend and the bending deflection fdef at which the control sample is destroyed, were determined. The maximum values of these indicators were also determined if the sample was not destroyed during the tests. During the experiments, regression models were obtained for output parameters of the bending force and bending deflection. Sample macrostructure and metal hardness distribution on rolling surface of the rails welded joint were studied. A new method of resistance butt welding was developed, which makes it possible to obtain a welded connection of P65 type rails of DT350 category with properties that exceed the technical requirements of the mentioned state standard.

Book ChapterDOI
01 Jan 2020
TL;DR: The finite element model of a welding connection part is developed by employing CSEAM element in NASTRAN and its feasibility for representing a seam weld is investigated and a damage detection method by updating the properties of the built CSEam elements is proposed for welding quality assurance.
Abstract: Seam welds are widely used in assembled structures for connecting components. However, the dynamic effects of a seam weld are often difficult to characterise in numerical models for several reasons: (1) it is often not wise to build a fine mesh on the seam line which will add considerable computational cost for a structure with many welds, (2) the mechanical properties of weld materials are not well known; (3) sometimes some geometric information about welds is not known beforehand. In this work, the finite element model of a welding connection part is developed by employing CSEAM element in NASTRAN and its feasibility for representing a seam weld is investigated. Based on this result, a damage detection method by updating the properties of the built CSEAM elements is also proposed for welding quality assurance. The damage takes the form of a gap in the weld which causes a sharp change of model strain energy at the edges of the gap for certain vibration modes. Specifically, the model strain energy shape is used as the objective function. A Kriging model is introduced for efficiency and simulation of a T-shaped welded plate structure to demonstrate the effectiveness of this method.