Welding Applications Research Articles

Consideration on the Applicability of Electron Beam Welding for the Manufacture of Small Modular Reactor

The overall technology required for the application of electron beam welding to ultra-thick plate pressure vessel in small modular reactors was considered. Electron beam welding has the advantage of reducing the manufacturing time compared with traditional arc welding, but it requires the construction of complex equipment and the establishment of related process technology. Based on the thickness of 150~250 mm, the electron beam welding equipment for application to SMR pressure vessel requires large-capacity equipment of 120~170 kV, 150 kW or more, which has never been commercially manufactured so far. A stable beam must be maintained for a constant time. Anti-arcing and seam tracking functions are also required. Electron beam welding of low-alloy steel has superior characteristics in terms of strength and toughness compared with arc welding. The welded area can be made into a base material by solution heat treatment. Cleaning and gap control are important for weld quality. Weld area should not be affected by magnetic fields. As circumferential welding overlaps in span at the welding start and end, it requires precise setting of welding parameters. For welding of large pressure vessel, customized cylindrical vacuum chamber or local vacuum chamber are suitable. It must be shielded from X-rays generated during welding.

A Study on Bead on Plate (BOP) Test for Laser Welding Application of Stainless Steel to Liquified Hydrogen Tank (PART I: STS 304)

Liquified hydrogen is considered a new energy resource to replace conventional fossil fuels due to environmental regulations by the IMO. When building tank for the storage and transportation of liquified hydrogen, materials need to withstand temperatures of -253°C, which is even lower than that of LNG (-163°C). These materials mainly include austenitic stainless steel and high-manganese steel, especially STS 304 steel mainly used to build liquified hydrogen tank. When building the tanks, both the base material and welding zone need to have excellent strength in cryogenic condition, however, manual arc welding has several issues due to prolonged exposure of the base material to high temperatures. Laser welding, which has some benefits like short period of exposure time and decrease of thermal affected zone, is used many industries. In this study, to determine the laser butt welding condition for STS 304 steel, laser bead on plate welding was conducted. After the BOP test, cross-section observation was conducted to analyze the penetration characteristics. After observation, four bead parameters were measured, and these tendency result of laser welding for STS 304 steel can be used as conditions laser butt welding of STS 304 steel.

Investigation of the influence of pulse parameters on the resulting weld seam quality in pulsed electron beam welding of AW 6061

Utilizing pulsed lasers in favor of a continuous wave in laser beam welding is a well-established method to achieve higher process efficiency and reduce heat input into the workpiece, which is especially useful for thin-walled workpieces (Steen, 2005). In addition, pulsed processes have shown to lead to smaller grain sizes due to higher cooling rates, which can lead to a reduction in hot cracks in some aluminum alloys (Beiranvand et al., 2019). Since an electron beam can also be pulsed, a technique industrially utilized in electron beam drilling, the same principles apply (Schultz, 2000). However, pulsed electron beam welding is rarely used in industrial welding applications due to the risk of pores, spiking and sputtering resulting from the pulsed process dynamic, especially in the deep welding regime (Kautz, 1991). This study aims to develop a pulsed electron beam welding process for AW 6061 sheet metal, which is susceptible to hot cracking. The influence of the welding and pulse parameters, as well as the combination of a pulsed beam with high frequency beam oscillation is discussed. Furthermore, suitable welding parameters for pulsed electron beam welding of AW 6061 are developed, and the increased efficiency of pulsed welding is shown by comparison to continuous welds.

Numerical analysis of arc physics and energy transfer under circumferential gas constraint effect

Energy dispersion and easy instability associated with arcs, the traditional metal processing heat source, restrict its development and application in the modern high-precision welding and additive manufacturing. This work aims to study the characteristics of a novel arc under circumferential gas constraint effect which can improve the arc stability and processing accuracy. A magnetohydrodynamics model was established to calculate the arc physics and heat transfer, considering the electron emission characteristics of tungsten and the effect of metal vapor. It indicates that the annular flexible constrained gas flow can significantly increase the physical characteristics such as arc temperature, plasma flow velocity and current density compared with traditional free arc which is named GTA. The arc heat generation increasement of the novel arc makes the heat transfer from arc to base metal higher than that of GTA. The additional annular gas flow inhibits the diffusion of metal vapor, stabilizing the arc and protecting the tungsten electrode from contamination. However, as the arc length decreases, eddy of arc plasma flow appears inside the arc, which can cause metal vapor to contaminate the tungsten. It's found that this novel gas flow constrained arc needs to be applied with a small current when welding with small arc length to avoid the eddy. Finally, the accuracy of the calculation model is verified by experimental detection of arc temperature.

Electron Gun Generation and Application in Welding, Lithography and Treatment of Pollutants

Electron Gun Generation and Application in Welding, Lithography and Treatment of Pollutants

Dirençli Punta Kaynağı Prosesinin KNN ve CART Makine Öğrenimi Teknikleri ile Değerlendirilmesi

Spot welding, a type of resistance welding, is a welding application widely used in the production area and it is a common method for joining metal sheets. The spot-welding process is widely used in many production areas, especially in the automotive industry, radiator, and wire mesh production. Spot welding in car production lines is mainly performed by robotic applications. Industry 4.0 and digital transformation trends have led to unprecedented data growth. Nowadays, the manufacturing industry benefits from the power of machine learning and data science algorithms to monitor production processes and make predictions for quality, maintenance, and production optimization. Applying machine learning algorithms reduces the duration and cost of experiments. This study aims to confirm whether the spot welding, applied by robotic arms, is within the ideal spot-welding norms, in real production area. The ideal parameter norms were evaluated by using KNN and CART machine learning algorithms. To use real production data, this study was executed in the body production assembly line, which is selected as the pilot area, at TOFAŞ factory. The data set used in this research consists of the welding parameters of the current year, 2023. By running machine learning algorithms on the dataset, the performance evaluation of each algorithm was examined and the most appropriate estimation method was determined. In the experiments, the best F1-Score value was obtained by the CART model with 93%.

Buried Arc Application in Hybrid Laser-Arc Welding of Thermo-Mechanical Control Process Steels

Buried Arc Application in Hybrid Laser-Arc Welding of Thermo-Mechanical Control Process Steels

A novel 3D vision-based robotic welding path extraction method for complex intersection curves

With the rapid development of robot technology, robotic welding technology has gradually been applied in the complex co-main intersection pipeline welding field. However, due to the existence of clamping errors and processing dimensional errors in intersecting pipes of the same specification, the actual welding path deviates from the taught path and cannot meet the accuracy requirements of robot welding, which further hinders the development and application of robotic welding in this field. To solve these problems, we propose a 3D vision-based robotic welding path extraction method for complex intersecting curves without programming and teaching. We begin by selecting the complex co-main intersection pipeline as the research object and building a robotic welding system based on 3D vision. Through mathematical analysis of the complex intersecting pipe model and an analysis of the internal coordinate transformation relationship within the welding system, we establish a mathematical model of the complex intersection curves at any clamping position in the manipulator coordinate system. On this basis, We propose a multi-view point cloud stitching method using Eye-in-Hand calibration and the ICP algorithm to obtain a complete co-main intersection pipeline point cloud. Subsequently, we propose a mathematical model parameter-solving algorithm based on the co-main intersection pipeline point cloud. Finally, the obtained actual parameters of the workpiece are combined with the established mathematical model to extract the welding path of the robot’s current position. Experimental results demonstrate that the proposed method can automatically extract welding seams for complex intersection curves without the need for programming and teaching.

Investigation of joints from corrosion-resistant steels obtained by energy-saving rotary friction welding technology

In this article the possibility of application of rotary friction welding for joining parts from stainless steels is evaluated on the example of 10Cr17Ni13Mo2Ti steel. Application of rotary friction welding allows to refuse post-weld heat treatment, which is labor-intensive, energy-consuming and environmentally harmful operation. For this purpose, cylindrical samples of 20 mm in diameter were made from the above steel using friction welding without subsequent heat treatment. The microstructure, microhardness measurement, tensile and impact bending tests were carried out. The microstructure study showed that the weld width across the entire cross-section does not exceed 12 μm. It has an irregular wavy shape with a fine-grained structure. Tensile tests showed that the average value of yield strength of samples with welded joint is 1.6% higher than the same value of samples from the base metal, but the average value of time resistance is lower by 5.6%. Impact bending test results showed that the average impact toughness of welded samples is almost the same as that of base metal samples. According to the results of studies concluded that the weldability of steel 10Cr17Ni13Mo2Ti using friction welding is good, welded joints are obtained high quality.

The Application of Electron-Beam Welding in Pellet Mold Preparation

This paper provides insight into the application of electron-beam welding in pellet mold preparation, highlighting the importance of the combination of electron-beam welding and pellet mold preparation in the fields of microstructure joining and micro- and nanostructure preparation. Precise material joining and microstructure fabrication can be achieved by the precise control of electron-beam welding and the shape adjustment of pellet molds. These applications hold significant potential in the modern industrial field, providing robust support for the development of new materials and the growth of the petrochemical industry. This paper asserts that in the future, the ongoing development of electron-beam welding and pelletizing template technology will unlock new possibilities in the field of petrochemicals, fostering progress in science and technology.

Advances in ultrasonic welding of lightweight alloys: A review

Abstract The lightweight alloy sheet materials have been widely used in industries such as automobiles, aviation, and aerospace. However, there are huge challenges in the structural joining process. Likewise, industries are probing new technologies and are rapidly adapting to more complex light alloy materials. The ultrasonic metal welding is a reliable solid-phase joining technology, which has incomparable development prospects in the high-strength joining of lightweight alloy sheet materials. This article summarizes the research progress of ultrasonic welding of aluminum alloy, magnesium alloy, and titanium alloy thin plates in recent years. The key features of this review article are the ultrasonic welding process, advantages, applications, and limitations. It introduces the welding process parameters to explore the breakthroughs for straightforward direction. Furthermore, to strengthen the phenomena, the current state of the ultrasonic welding of lightweight alloys and their future perspectives are also reflected.

Optimization of ultrasonic welding parameters for better seam performance

PurposeUltrasonic welding is an emerging apparel manufacturing technique. However, the applications are widely explored in the field of technical textiles, with less exploration in the apparel endues. The purpose of this study is to explore the application of ultrasonic welding in apparel by analyzing the impacts of different parameters.Design/methodology/approachThis study analyzed the influence of ultrasonic welding parameters, including pressure, welding speed and ultrasonic power on the seam performances (seam strength, seam bursting strength, seam thickness and seam stiffness). The parameters are optimized using Box–Behnken experimental design to achieve better seam performances.FindingsThe properties of ultrasonic seams are influenced by welding and fabric properties. Ultrasonically welded seams showed better performances in the case of comfort properties of seams, whereas the functional properties are lesser compared to conventional seams.Originality/valueThe findings of the research clearly outline the level of influence of different parameters on the performance of the ultrasonically welded seams in knitted fabrics, which can greatly help in applying ultrasonic welding manufacturing methods in apparel manufacturing.

Design of continuous-duty high-power converter for multi-purpose welding applications

One large-current high-power full-bridge DC-DC converter is often used to cater several multi-characteristic welding loads. The load could be a welding arc or a conductive molten flux. The contour of operating point (voltage-current) of each load type is different. The converter often operates under complex light-load conditions. The design of such high power continuous-duty converter needs to meet three objectives – desired control performance, high across-the-load efficiency, and superior thermal management. To address the thermal issues, this article proposes to use parallel-connected converter modules. It helps distribute the power loss over larger component base; increased surface area would assist the heat removal process. For high operating efficiency, this article proposes superior component engineering in each module. And, for high across the load efficiency, this article proposes to enable or disable an efficient converter module based on the current demand. It means each converter module is equipped to feed the connected load in stand-alone mode. For reduction of power loss, this article elaborates the role of each critical component. The distribution of heat loss would be optimally shared if the current sharing by converter modules is equal, but it needs to be compatible to the dynamic behavior of multi-input process loads. This research proposes and practically validates that single PWM-controller driven parallel-connected converter-modules are not only compatible to process dynamics, the idea would achieve proper current sharing among similar components.

A review of friction stir welding parameters, process and application fields

It is important to join materials for systems that require high-performance and to minimize the defects that may occur during this joining. Welding is the most common way for joining materials but for lightweight and similar/ dissimilar materials, Friction Stir Welding preferable for its high-performance joining properties. Lightweight and durable materials such as aluminum alloys are widely used in sectors such as defense industry, aerospace industry, automotive industry, and high-speed train manufacturing. Some of these materials cannot be welded by conventional methods due to their high thermal conductivity and low melting point. In welding processes, material properties are expected to be as close as possible to base material. Friction stir welding (FSW) is a joining method that provides welding below the melting point of materials that cannot be welded by conventional methods or where the welding process causes the mechanical structure of the material to deteriorate. In this study, Friction Stir Welding process, advantages and disadvantages and application fields of Friction Stir Welding were examined.

Effect of laser-arc synergy on melting energy in laser-CMT hybrid welding of aluminum alloy

The physical process of laser-arc synergy in laser-cold metal transfer (CMT) hybrid welding of aluminum alloys is extremely complex and difficult to observe, which limits our understanding of laser-arc synergy and the industrial application of laser-CMT hybrid welding. In this paper, the laser-arc synergistic effect is studied quantitatively by the change of melting energy. Therefore, the dimensionless parameter (ψ) is introduced to discuss the effect of heat source guidance, energy distribution and distance of laser and arc (DLA) on melting energy increment. The results show that the novel laser-arc simultaneous co directional hybrid welding (no-guided) process increases ψ by 4.3 times and 1.8 times compared to CMT-guided and laser-guided processes, respectively. The laser-arc synergy is strongest when the laser power is 80% of the total power and DLA is 2 mm. The quantitative analysis method in this paper can be extended to the study of other hybrid heat sources, and this research can facilitate the optimization of the welding process and a better understanding of the hybrid welding mechanism.

Enhancing Microstructural, Textural, and Mechanical Properties of Al-Ti Dissimilar Joints via Static Shoulder Friction Stir Welding

Abstract The present study explores the application of static shoulder friction stir welding (SSFSW) to address the challenges of poor mechanical properties in conventional Al-Ti dissimilar friction stir joints, which arise due to significant material mixing and the formation of thick intermetallic layers. The results show that SSFSW inhibited material mixing and the mutual diffusion of Al and Ti were suppressed due to lower heat input. Mutual interdiffusion of Al and Ti was directed by an exothermic chemical reaction, forming an Al5Ti2 – Al3Ti sequence due to sluggish diffusion of Al in Ti at a temperature of 512°C achieved in this study. The microstructure at stir zone (SZ) comprised equiaxed grains with Ti particles acting as dispersoids for nucleation, whereas the presence of large Ti blocks at SZ of Conventional FSW (CFSW) resisted plastic deformation, resulting in non-homogeneous concentration of dislocations near its interface. A significant decrease in grain size at all the critical zones of weldment was due to rearrangement of dislocations through slip-and-climb mechanism, as evidenced by the occurrence of dynamic recrystallization. Emergence of γ-fiber and basal fiber texture increased the tensile strength of SSFSW to 289 MPa, which is about 11.2% higher than CFSW, with joint efficiency of about 88%. The study also analysed the contribution of various strengthening mechanisms to the yield strength improvement of SSFSW weldments in detail of SSFSW weldments in detail, and the results showed that grain boundary strengthening contributed the most to strength improvement in SSFSW.

Acceleration of metal plates by hybridization of electrical and chemical energy for potential application in high-velocity impact welding

Vaporizing foil actuator welding is employed to connect dissimilar metals by utilizing the energy of an electrical explosion as the driving force for flyer plate acceleration. Herein, the electrical and chemical energies of explosives were combined to increase flyer plate velocity. A metal foil or wire mesh was used as an actuator, and a small amount of explosives was placed on the foil. Uniform acceleration of the flyer plate on the actuator was recorded using a high-speed video camera. The electrical energy applied to the actuator was measured synchronously by filming. The explosion of chemical explosives was successfully initiated owing to the electrical explosion of the actuator. In all experiments, the combination of the electrical explosion and chemical reaction improved the acceleration of the samples, facilitating higher velocities. The impact of the actuator type (mesh or foil) and the electric discharge parameters on the performance was studied. While foil actuators were more efficient in experiments on electric explosions alone, mesh actuators were superior when the chemical explosive was added. Explosions of the mesh actuator could initiate low density pentaerythritol tetranitrate (PETN) (the space-filling rate of PETN was approximately 30%). An explosive force of 0.3 g of PETN was converted into a driving force, imparting the flying plate with a velocity greater than 210 m/s. Electrical energy consumption for PETN initiation may be assumed to have an insignificant impact on flyer plate acceleration. In future, the proposed method may be used to connect heavier and thicker materials without expensive high-performance capacitors.

Study on infrared emissivity model based on perturbation method and Kirchhoff approximation and its application in aluminum alloy welding

Infrared temperature measurement ubiquitously finds applications across multifarious domains. The surface infrared emissivity constitutes the critical parameter influencing the precision of infrared temperature measurement. Therefore, investigating the surface infrared emissivity is of tremendous significance. This paper establishes an infrared emissivity analytical model for rough texture surfaces by considering the repercussions of roughness on the infrared emissivity of material surfaces. First, power spectrum analysis of random roughness is performed. The positive and negative power law components of the rough surface model are constructed using the Monte Carlo method and fractal theory, respectively. Second, based on the perturbation method and Kirchhoff approximation, the infrared emissivity model for rough textured surfaces is established. Third, the infrared emissivity of rough textured surfaces with different fractal dimensions (D), characteristic length scales (G), and surface textures is simulated using the FDTD optical simulation software to validate the efficacy of the infrared emissivity model. Finally, the infrared emissivity model is applied to the temperature measurement system of aluminum alloy friction stir welding. The infrared measurement precision before and after rectification is contrasted and scrutinized to validate the accuracy of this model.

Laser welding of GH3539 alloy for molten salt reactor: Processing optimization, microstructure and mechanical properties

GH3539 is a most promising material for next-generation molten salt reactors (MSR) due to its excellent performance in harsh high temperature molten salt environments. To promote the application of laser welding of GH3539 alloy in the molten salt reactor, the effect of various laser welding parameters on the weld geometry was investigated, as well as the microstructure and mechanical properties of GH3539 laser welded joints. The results indicate that GH3539 alloy has good laser weldability. The weld geometry of the laser welded alloy joint is significantly affected by the laser welding parameters. After processing optimization, the optimized laser welding process parameters were obtained. The microstructure close to the fusion line is a columnar crystal growing perpendicular to the direction of the fusion line. The core of the central portion of the welded joint consists of equiaxed crystals. No apparent “softened” heat-affected zone (HAZ) was discovered in the laser-welded joints. The hardness of the weld metal (WM) is approximately 130% of the hardness of the base metal (BM). Hardness values in different areas of the WM display unique distributions due to the influence of microstructure and intergranular carbides. A small amount of tiny solidification cracking, liquidation cracking is found in welded joints. Compared to specimens at room temperature (RT), both the tensile strength and elongation dropped significantly under the circumstances of elevated temperature. All fractures are located in the BM with a brittle fracture pattern.

Interfacial evolution mechanism of W/Cu explosive welding interface affected by preheating

Tungsten/copper (W/Cu) laminated composites possess high application potential in electronic, aerospace, and nuclear industries by combining the advantages of W and Cu. Among various fabrication methods, the explosive welding method is regarded as one rapid and cost-effective approach to producing W/Cu laminated composites considering the huge differences in physical properties between W and Cu. However, the lack of investigation on the bonding interface evolution between thick W plate and Cu plate inhibits the potential application of explosive welding on the large-scale production of the W/Cu laminated composites. In this study, the crack-free thick W/Cu laminated composites have been obtained successfully through the hot explosive welding approach, and the evolution mechanism of wavy interface formation is studied through numerical simulation and experimental investigation. The microstructure of welded W/Cu interface zone is further characterized to analyze the evolution mechanism of the wavy interface and corresponding bonding features. Moreover, the results of the mechanical property tests, such as compression shear, direct tensile, and micro-hardness tests, demonstrate that the welded W/Cu laminated composite features outstanding mechanical properties. Our study reveals the formation mechanism of the W/Cu interface during the hot explosive welding process and provides a rapid and efficient strategy to produce large-size W/Cu laminated composite with a thick W layer.