Solid Wire Research Articles

Evaluation of Continuous GMA Welding Characteristics Based on the Copper-Plating Method of Solid Wire Surfaces

Gas metal arc welding (GMAW) is widely used in various industries, such as automotive and heavy equipment manufacturing, because of its high productivity and speed, with solid wires being selected based on the mechanical properties required for welded joints. GMAW consists of various components, among which consumables such as the contact tip and continuously fed solid wire have a significant impact on the weld quality. In particular, the copper-plating method can affect the conductivity and arc stability of the solid wire, causing differences in the continuous welding performance. This study evaluated the welding performance during 60 min continuous GMAW using an AWS A5.18 ER70S-3 solid wire, which was copper-plated using chemical plating (C-wire) and electroplating (E-wire). The homogeneity and adhesion of the copper-plated surface of the E-wire were superior to those of the C-wire. The E-wire exhibited better performance in terms of arc stability. The wear rate of the contact tip was approximately 45% higher when using the E-wire for 60 min of welding compared with the C-wire, which was attributed to the larger variation rate in the cast and helix in the E-wire. Additionally, the amount of spatter adhered to the nozzle during 60 min, with the E-wire averaging 5.9 g, approximately half that of the C-wire at 12.9 g. The E-wire exhibits superior arc stability compared with the C-wire based on the spatter amount adhered to the nozzle. This study provides an important reference for understanding the impact of copper plating methods and wire morphology on the replacement cycles of consumable welding parts in automated welding processes such as continuous welding and wire-arc additive manufacturing.

Multi-pass laser welding with cut-wire particles of 50 mm thick steel plates

Multi-pass laser welding with filler wire feeding shows significant potential for welding thick plates. However, this method faces challenges due to the need for edge preparation and stringent control of parameters such as wire feed speed and the relative positioning to the laser beam. Utilizing cut-wire particles instead of solid wire may address these limitations. This investigated the usage of cut-wire particles in multi-pass laser welding of 50 mm thick square groove butt joints. The study involved welding experiments to optimize the amount of cut-wire particles, laser power density, and travel speed for root and buildup passes. The final pass employed hybrid laser-arc welding to compensate for the voids between the cut-wire particles. The joints were successfully welded in eight passes. Mechanical testing demonstrated that the welded joints exhibited strength surpassing that of the base metal. The heat-affected zone displayed a hardness exceeding 350 HV. The fusion zones of the hybrid and buildup passes showed an impact toughness of 100 J, while the root pass fusion zone exhibited an impact toughness of approximately 45 J. This difference was attributed to the presence of a bainitic/martensitic microstructure in the root pass, compared to a mixture of acicular and grain boundary ferrite in the hybrid and buildup passes.

Calculation of Resistances and Inductances in Multi-Conductor Systems Including Solid and Litz Wires Using the 2-D Boundary Element Method

Calculation of Resistances and Inductances in Multi-Conductor Systems Including Solid and Litz Wires Using the 2-D Boundary Element Method

Effects of deposition strategies on microstructure and mechanical properties of wire arc additive manufactured CoCrFeNiMo0.2 high-entropy alloy

High-entropy alloys (HEAs) have great potential for application in various fields due to their excellent performance. However, there are few reports on wire arc additive manufacturing of HEAs. In this study, CoCrFeNiMo0.2 HEA solid wire was prepared and used for WAAM based on cold metal transfer for the first time. Different deposition strategies (namely single-pass (SP), oscillation (OS), and multi-parallel pass (MPP)) were used to prepare metal wall samples of different thicknesses. The HEA samples' microstructure with different deposition strategies were explored by optical and scanning electron microscopy, as well as the electron backscatter diffraction method. Microhardness and tensile tests were used to evaluate the mechanical properties of different samples. The results prove that SP and MPP samples exhibit rougher surfaces due to heat accumulation. The OS sample has the best molding and an effective deposition ratio of up to 91.5 %. The composition of columnar grain grown along the deposition direction with strong {100}<001> cubic texture in both SP and OS samples. Therefore, these two samples have similar mechanical properties, and the mechanical performance in the vertical direction is better than that in the horizontal direction. Due to the complex internal thermal effects and remelting effects between welds, the internal structure of the MPP sample exhibits no obvious preferred orientation. Therefore, the anisotropy of mechanical properties is significantly alleviated.

Impact of Ultrasonic Welding Parameters on Weldability and Sustainability of Solid Copper Wires with and without Varnish.

This article contains an advanced analysis of the properties of solid wire electrical contacts produced by ultrasonic welding, both with and without varnish. The main disadvantage of ultrasonic welding of thin wires is the inability to achieve acceptable peel force and tensile strength, which is mainly due to the deformation and thinning of the wires. This study deals with ultrasonic welding using a ring of thin solid copper wires that minimises the deformation and thinning of the wires. The influence of welding parameters such as energy, pressure and amplitude were systematically analysed. Based on these parameters, the optimum welding programme and control method was determined to weld unvarnished and varnished wires. The investigations included electrical resistance tests, optical microscopy, micro-hardness measurements, peel tests and tensile tests, and the measurement of energy consumption. The results showed no significant differences in microstructure and hardness between varnished and unvarnished joints. Ultrasonic joints of varnished wires achieved lower electrical conductivity (by 38%), lower tensile strength (by 3%) and higher peel strength (by 7%), while the welding process was more sustainable in terms of energy (by 6.6%) and time consumption (without preprocessing).

Preparation and formation mechanism of (W) WC/Fe bundle reinforced iron matrix composites

To address the issue of strength and toughness inversion in traditional metal matrix composites, which are reinforced by uniformly distributed ceramic particles, this research developed a novel space bundle configuration of reinforced iron matrix composite using tungsten wire (W) and tungsten carbide (WC). This composite was prepared using a lost foam casting process combined with in-situ reaction. Microstructural analysis revealed that WC particles are distributed along the tungsten wire, with larger particles at the center and smaller ones at the edges. The formation of the reinforcement occurs in two stages: first, a solid-liquid reaction between the solid tungsten wire and molten iron during the lost foam casting process, promoting WC formation at high temperatures and carbon potential; second, an in situ solid-solid reaction where Fe diffuses and Fe3W3C decomposes, forming a composite structure of WC and α-Fe. The composite obtained at 1100 °C for 9 h exhibited a compressive strength of 836.59 MPa and a fracture strain of 18.69 %, representing increases of 48.46 % and 48.69 % respectively compared to gray cast iron (GCI). The (W) WC/Fe bundle reinforcement effectively enhances the strength and toughness of the composite through the high volume fraction and gradient distribution of WC particles, combined with the synergistic effect of α-Fe. This research provides a new strategy for improving the mechanical properties of composite materials and resolving the issue of strength-toughness inversion.

Effect of Heat Input on Microstructure and Microhardness in WAAM

Experiments were carried out for WAAM of samples using electric arc and additive material in the form of solid wire grade G3Si1. The layers were built-up with one transition each. Metallographic macro- and microsections were made from the obtained samples. The macro- sections are used to determine the locations of microhardness measurements. The microsections were used to measure the microhardness and to illustrate the microstructure. The analysis of the obtained results shows that the heat input and the interlayer temperature are of crucial importance for the obtained mechanical characteristics of the built-up samples. The microstructure of the obtained layers varies along the height of the built-up samples thus witnessing for the thermal treatment occurring in each layer except the last one as a result of applying the subsequent layers.

Effect of Cr Element in Gas-Shielded Solid Wire for Oil and Gas Long-Distance Pipeline on Microstructure and Low Temperature Toughness of Weld.

In this paper, the influence of Cr element on the mechanical properties of welded joints of gas-shielded solid wire used in oil and gas long-distance pipelines was studied by means of tensile test, impact test, and hardness test, and the microstructure and crack propagation path of weld were characterized by means of an optical microscope, scanning electron microscope, and electron backscattering diffraction. The results show that with the addition of Cr, the strength and toughness of the weld are significantly improved, in which the tensile strength is increased from 607 MPa to 656 MPa, and the impact toughness is increased from 126.37 J to 223.79 J. The proportion of the ferrite side plate in the weld structure is reduced by about 20%, and the effective grain size of acicular ferrite is reduced by about 15%. The reason is that the addition of the Cr element improves the hardenability of the weld structure, inhibits the formation of the ferrite side plate, and promotes the effective refinement of acicular ferrite, which increases the proportion of high-angle grain boundaries in the weld, effectively hindering the crack propagation, improves the crack propagation work, and thus improves the strength and toughness of the weld.

Microstructure and Mechanical Properties of Low Stacking-Fault Energy Cu-Based Alloy Wires

Innovations in electronic devices and their capabilities have driven the demand for improved conductive materials relevant to device fabrication. To gain insights on developing solid solution-type Cu alloy thin wires with a superior balance of strength and conductivity, this study investigated variations in the microstructures and properties of pure Cu wires and Cu–5 at. pct Zn, Cu–5 at. pct Al, and Cu–5 at. pct In alloy wires during intense drawing and analyzed the effects of stacking-fault energy (SFE) of Cu alloys on their microstructural evolution. During the initial drawing stages, lower SFE Cu–5 at. pct Al and Cu–5 at. pct In alloys yielded more high-density deformation twins than pure Cu and Cu–5 at. pct Zn. Deformation twins promoted grain refinement during drawing. Effective grain refinement and dislocation accumulation during drawing in low-SFE Cu alloys substantially strengthened them without adversely impacting electrical conductivity. During intense drawing in the Cu–5 at. pct In alloy wires, ultrafine fibrous grains (diameter ~ 80 nm) and a high-dislocation density yielded excellent tensile strength and conductivity. These results indicate that adjusting the solute element content in Cu matrix to reduce SFE and optimizing deformation strain via wire drawing significantly improve alloy wire performance.

The Influence of Variable Plasma Welding Parameters on Weld Geometry, Dilution Factor, and Microhardness

Weld surfacing is the process of applying a layer of metal to the surface of metal objects by simultaneously melting the substrate. As a result of this process, the metal content of the padding weld can be as high as several tens of percents. It is a method used to regenerate machine parts and improve the properties of the surface layer, increasing its resistance to abrasion, corrosion, erosion, and cavitation. It also supports the repair and creation of permanent protective coatings in the engineering, automotive, energy, and aerospace industries. This makes it possible to repair damaged parts instead of completely replacing them, saving time and production costs. Plasma surfacing technology is used for components that require high hardness and corrosion resistance under various environmental conditions. Plasma wire surfacing is not sufficiently presented and described in the current literature, which creates problems in determining the appropriate process parameters. The influence of variable plasma surfacing parameters on steel C45 significantly affects surfacing weld geometry, the dilution factor, and microhardness. Higher currents can increase the dilution factor, integrating more base metal into the weld pool, which may alter the chemical composition and mechanical properties of the weld. Variations in surfacing speed and heat input also affect the microhardness of the surfaced joint, with higher heat inputs potentially leading to softer welds due to slower cooling rates. Optimizing these parameters is essential to achieving desired surfacing weld characteristics and ensuring the structural integrity of C45 steel joints. This paper presents the influence of varying plasma surfacing parameters on the surfacing geometry, the dilution factor, and microhardness. The tests were carried out on a Panasonic TM-1400 GIII automated surfacing machine with CastoMag 45554S solid wire as the filler material. Flat bars of C45 steel were prepared, and then the variable parameters of the surfacing process were developed. Tests were carried out to determine the dilution factor, followed by microhardness measurements. The results showed a significant dependence of the effect of the parameters on the surfacing geometry and the dilution factor.

Comparative Process Parameter Optimization For Wire Arc Additive Manufacturing (WAAM) of E120C-GH4 Metal Cored and ER120S-G Solid Wire

Comparative Process Parameter Optimization For Wire Arc Additive Manufacturing (WAAM) of E120C-GH4 Metal Cored and ER120S-G Solid Wire

Green Synthesis of Copper Oxide Nanoparticles from Waste Solar Panels Using Piper nigrum Fruit Extract and Their Antibacterial Activity

To promote environmental development and sustain resource circularity, recycling metals from electronic waste is essential. Electronic waste is a significant secondary source of metals, with its production increasing rapidly and most remaining unrecycled. In solar panels, copper is the second-most-valuable metal after silver. We propose an innovative method to recycle copper from waste solar panels and convert it into copper oxide nanoparticles (CuONPs) using a green synthesis method. Synthesizing CuONPs is advantageous due to their large surface area compared to bulk material. Nitric acid, a strong oxidizing agent, was used to leach copper from solid copper wires in waste solar panels. A green synthesis method, following a bottom-up approach, was employed using Piper nigrum fruit extract to synthesize CuONPs. The synthesized nanoparticles were characterized using various qualitative and quantitative techniques. Spectroscopic analysis confirmed the formation of CuONPs, and transmission electron microscopy revealed that the nanoparticles were spherical with sizes up to 60 nm. Biomolecules from the Piper nigrum extract were detected on the surface of the crystalline CuONPs. These nanoparticles exhibited antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus using a well-diffusion method, showing a larger zone of inhibition for E. coli compared to S. aureus. This research demonstrates the complete recovery of copper from waste solar panels and its conversion into useful CuONPs, which have potential medicinal applications.

A new Ti–Al–Cr–Mo–Zr titanium alloy welding wire: Stability, microstructure and mechanical properties

In order to improve the plasticity of titanium alloy welded joints, relevant scholars currently focus primarily on studying the mechanism of action of alloying elements Mo and V, such as reducing the phase transition temperature of the welded seam and ensuring a certain amount of β phase residue in the welded seam. In addition to improving the stability and strengthening ability of titanium alloy welded joint, it can also maintain a certain degree of plasticity of the welded joint. However, the poor impact toughness is still the key problem that restricts its long-term stable service in the harsh environment. Our work designed and developed a new Ti–Al–Cr–Mo–Zr solid welding wire, with the synergistic effect of Al, Cr, Mo and Zr, the welded seam microstructure and grain can be refined while ensuring the enough stiffness of the welding wire and its flatness during wire feeding into the designated working area. It ensures good wetting and spreading flow performance of the liquid molten pool metal in the welding process, so better welded seam formation can be obtained. The relative contents of α′ martensite and β phase in the welded seam are 76.79% and 23.21%, respectively. The residual β phase is interspersed between the α′ martensite of the slats. The β phase provides a path for the plastic deformation of the welded joint, making it easier for dislocation slip to pass the β/α′ interface. At the same time, more dislocation slip channels and a small number of fine twins can be found in the interior of α′ martensite, which can ensure the strength while taking into account the toughness. After testing, it is found that the average tensile strength of welded joints is 901 MPa, which is close to 95% of the base metal (BM), the average post-fracture elongation of welded joints is 21%, and the impact toughness value at room temperature is distributed between 25 J and 33 J, which meets the requirements of the synergistic effect of welded joint strength and plastic toughness. It is suitable for long-term stable service of Ti64 titanium alloy welding structure under harsh working conditions.

Research on the Welding Process and Weld Formation in Multiple Solid-Flux Cored Wires Arc Hybrid Welding Process for Q960E Ultrahigh-Strength Steel.

This paper proposes a novel welding process for ultrahigh-strength steel. The effects of welding parameters on the welding process and weld formation were studied to obtain the optimal parameter window. It was found that the metal transfer modes of solid wires were primarily determined by electrical parameters, while flux-cored wires consistently exhibited multiple droplets per pulse. The one droplet per pulse possessed better welding stability and weld formation, whereas the short-circuiting transfer or one droplet multiple pulses easily caused abnormal arc ignition that decreased welding stability, which could easily lead to a "sawtooth-shaped" weld formation or weld offset towards one side with more spatters. Thus, the electrical parameters corresponding to one droplet per pulse were identified as the optimal parameter window. Furthermore, the weld zone (WZ) was predominantly composed of AF, and the heat-affected zone (HAZ) primarily consisted of TM and LM. Consequently, the welded joint still exhibited excellent mechanical properties, particularly toughness, despite higher welding heat input. The average tensile strength reached 928 MPa, and the impact absorbed energy at -40 °C for the WZ and HAZ were 54 J and 126 J, respectively. In addition, the application of triple-wire welding for ultrahigh-strength steel (UHSS) demonstrated a significant enhancement in post-weld deposition rate, with increases of 106% and 38% compared to single-wire and twin-wire welding techniques, respectively. This process not only utilized flux-cored wire to enhance the mechanical properties of joints but also achieved high deposition rate welding.

Optimization of metal transfer in rutile flux-cored arc welding through controlled CO2 concentration in argon–CO2 shielding gas

In this study, we analyzed the impact of carbon dioxide concentration in argon–carbon dioxide shielding gas on droplet transfer characteristics in rutile flux-cored arc welding, employing titanium oxide as a primary wire flux component. The welding process was carried out at a welding current of 190, 220, 250, 280, and 310 A under an argon–CO2 shielding gas mixture with six levels of CO2 concentration of 0, 5 %, 10 %, 15 %, 20 %, and 25 % for a parametric study. Unlike the conventional solid wire welding trend, where the droplet transfer frequency decreases with the increase in carbon dioxide concentration, an increase in metal transfer frequency was observed with the increase in CO2 concentration from approximately 5 % to 20 %. The concentration reaching the maximum frequency was 20 % at 190 A, which decreased as the welding current increased, reaching 5 % at 310 A. Droplet initiation at the lower sheath end is succeeded by a gradual downward movement along the flux column's side after a few milliseconds. Upon reaching the lower end, the droplet forms a neck and undergoes separation. Thus, the length of the flux column directly impacts the duration of one droplet transfer cycle. The length was decreased by arc constriction when increasing CO2 concentration appropriately to concentrate beneath the flux column or by increasing the welding current to raise the arc temperature, which contributed to melting and shortening the flux column.

Insight into the morphological instability of metallic nanowires under thermal stress

HypothesisMetallic nanowires, particularly polyol-grown silver nanowires, exhibit a morphological instability at temperatures significantly lower than their bulk melting point. This instability is commonly named after Rayleigh's description of the morphological instability of liquid jets, even though it has been shown that its quantitative predictions are not consistent with experimental measurements. In 1996, McCallum et al. proposed a description of the phenomenon assuming a solid wire lying on a substrate. It is assumed that the latter description depicts more accurately the reality. ExperimentsNanowires with varying diameters have been deposited on silicon wafers. Statistical analysis of their radius and the wavelength of their periodical instability have been performed. FindingsMcCallum et al.'s model better aligns with experimental observations compared to Rayleigh's description. This validation provides a robust theoretical framework for enhancing the stability of nanowires, addressing a crucial aspect of their development.

Effect of Heat Input on the Metal Microstructure and Mechanical Properties of Q960 High‐Strength Steel Solid Core Welding Wire

Effect of Heat Input on the Metal Microstructure and Mechanical Properties of Q960 High‐Strength Steel Solid Core Welding Wire

Effect of mechanical vibration on the microstructure and mechanical properties of CO2/MAG welded joint of Q345B steel

Vibration assisted welding (VAW) has emerged as a successful replacement for heat treatments of arc welds to refine grain, reduce residual stresses and distortions and thus to improve its mechanical properties. In this paper, mechanical VAW would be applied on the 8 mm thickness Q345B steel CO2/MAG filler welding, and the filler materials are solid core welding wire and flux-cored welding wire, respectively. The results show that: with the application of vibration, the proeutectoid ferrite in the weld area becomes finer, and the dendrites in the columnar crystals become significantly finer and more evenly distributed. The microhardness value of the weld zone in the welded joint with vibration is higher than that in the welded joint without vibration. The tensile strength of the welded joint increased from 502.5 MPa to 551.0 MPa at the motor speed of 2700 r/min when using solid core welding wire, increase nearly 10%. While, the tensile strength was deteriorated after the motor speed increased to 3600 r/min, which decreased to only 412 MPa, and the decreasement reached 25% comparing with the motor speed of 2700 r/min. During the VAW, the tensile strength and impact value of the welded joints fabricated by flux-cored welding wire are obviously better than that fabricated by solid core welding wire.

One‐Step Synthesis and Deposition of Metal Oxides: NiO Quantum Dots as a Transport Layer for Perovskite Photovoltaics

One‐step synthesis and deposition of nickel oxide quantum dots using a gas‐phase microplasma process is demonstrated and their applicability as a transport layer for solar cell devices is shown. The process uses a solid nickel metal wire as sacrificial electrode, and the concentration of oxygen gas required in the synthesis is investigated. The quantum dots are characterized for physical, chemical, and optical properties and critical process parameters such as the process throughput are also estimated. Direct one‐step deposition directly on perovskite solar cells is carried out using a computer‐controlled x–y stage and the performance of the solar cell device is assessed.

Disinfection of Bacteria in Aerosols by Applying High Voltage to Stranded Wire Electrodes.

The inactivation of airborne pathogenic microorganisms is crucial to attenuate the dissemination of infectious diseases induced by airborne pathogens. Conventional air disinfection methodologies, such as ultraviolet (UV) irradiation and ozone treatment, have demonstrated limited efficacy. Consequently, we investigated the potential of employing pulsed voltages to effectively eradicate bacteria within aerosols. Our inquiry revealed that the bacterial disinfection rate increased proportionally with elevated applied voltage and frequency. For instance, when a pulsed voltage of 20 kV and a frequency of 500 Hz were applied, a substantial disinfection rate exceeding 6.0 logarithmic units was attained. Furthermore, with the utilization of the stranded wire anodes, the disinfection intensity could be augmented by up to 2.0 logarithmic units compared with the solid wire configuration. Through the utilization of a stranded wire electrode model, we scrutinized the electric field encompassing the electrode, revealing a non-uniform electric field with the stranded wire electrode. This observation indicated an amplified bacterial disinfection effect, aligning with our experimental outcomes. These findings significantly enhance our comprehension of efficacious approaches to electrically disinfecting airborne bacteria.