Short-circuiting Transfer Research Articles

Fabricating complex parts through optimizing weld bead geometry in WAAM: A comparative study of surface tension transfer and cold metal transfer

Wire arc additive manufacturing (WAAM) technology is being employed in industries such as aerospace, maritime and automotive to produce high-valued metallic parts. With a growing demand for products with complex structures, it is crucial to develop an effective and reliable method for fabricating such parts to meet the demand. Currently, cold metal transfer (CMT), is one of the waveform-controlled short circuit transfer processes, commonly adopted in the WAAM process to fabricate medium to large-scale parts due to its perceived low heat input. However, the approach of using synergic control of wire feed speed and torch travel speed to control weld bead geometry in CMT may not be applicable for fabricating parts with complex structures. In these circumstances, surface tension transfer (STT), a waveform controlled short circuit transfer process, or one of the alternative variants of controlled short circuit transfer with low heat input, may provide more options to control weld bead geometry. There appear to have been few systematic investigations of alternative controlled short circuiting variants for use in WAAM. This paper provides a comparative study to explore the potential of the STT process for fabricating parts with complex geometries in WAAM. Firstly, the working principles of the STT and CMT processes are reviewed. Then, the impacts of welding parameters in the STT and CMT on weld bead geometry are analysed based on experiment results. Finally, a comparison between these two welding processes with regard to flexibility in welding parameter adjustment, heat input and overlapping performance is conducted. Finally, a comparison between these two welding processes is conducted from three critical aspects: (i) Flexibility in parameter adjustment: STT has 333 % and 174 % larger average width and height variation ranges than CMT; (ii) Heat input: STT's heat input is 74.66 % higher than CMT's at TS = 300 mm/min; (iii) Overlapping performance: the average surface roughness of the tested CMT and STT groups is 0.1312 and 0.1823, respectively. Suggestions for using STT and CMT to fabricate parts with complex geometries are provided accordingly.

Heat and mass transfer behavior in CMT plus pulse arc manufacturing

The metal transfer mode, temperature distribution, flow behavior, and microstructure characteristic in the process of cold metal transfer plus pulse (CMT+P) arc manufacturing were investigated by the in-situ observation and numerical simulation. A novel coupling model for droplet-pool interaction under the CMT+P arc was established, along with a new heat source model that considered Marangoni forces on droplets. These innovations provided significant insights into the heat and mass transfer mechanisms in the CMT+P hybrid arc manufacturing process. The results show that the droplets generated by the CMT+P hybrid arc exhibited a mixed transfer mode: short-circuit transfer in the CMT period and projected transfer of one droplet per pulse during the pulse period. The short-circuit transfer was more stable than the projected transfer, attributed to the smooth transfer of droplets to the molten pool through the liquid metal bridge, dominated by surface tension and Marangoni forces. The main energy of the molten pool was provided by droplets, which had a dominant ability to melt the substrate. However, the liquid metal bridge in the CMT period slowed down the heat transfer to the molten pool and had significant oscillating and stirring effects. During the pulse period, the droplet was accelerated and projected transfer by gravity and electromagnetic force. After solidification, the microstructure exhibited an alternating distribution of columnar and equiaxed grains from the bottom-up in the monolayer deposited layer, with a deflected fusion interface towards the scanning direction. At the top of the deposited layer, coarse columnar grains were distributed obliquely or laterally, inhibiting the growth of equiaxed grains and forming a distinct boundary with the equiaxed grains below.

Preparation and sensing performance of wet-spun fabric triboelectric nanogenerator for energy harvesting

Flexible, wearable triboelectric nanogenerators (TENGs) monitoring human movement and health signals have received more attention recently. In particular, developing a flexible TENG combining stress, strain, electrical output performance and durability becomes the current research focus. Herein, a highly stretchable, self-powered coaxial yarn TENGs were manufactured using a low-cost, efficient continuous wet-spinning method. Carbon nanotube/conductive thermoplastic polyurethane (MWCNT/CTPU) and polyvinylidene fluoride-hexafluoropropylene were utilized for the coaxial fibers conductive layers and dielectric layers, respectively. Fibers were continuously collected over a length of 10 m. Excellent electrical output with an open-circuit voltage (Voc) of 11.4 V, short-circuit current (Isc) of 114.8 nA, and short-circuit transfer charge (Qsc) of 6.1 nC was achieved. In addition, fabric TENGs with different two and three dimensional structures were further prepared by the developed coaxial fibers. The corresponding electrical output properties and practical performance were discussed. Results showed that the four-layer three-dimensional angle interlocking structure exhibited the optimal performance with an open-circuit voltage (Voc) of 38.4 V, short-circuit current (Isc) of 451.5 nA, and short-circuit transfer charge (Qsc) of 23.1 nC.

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.

Heat transfer performance and optimal design of shallow coaxial ground heat exchangers

The heat transfer performance of coaxial ground heat exchangers (GHEs) can be strongly influenced by their structure parameters and improved by the optimal design. To improve the heat transfer efficiency, this study proposed a coaxial GHE with large pipe diameters and thick inner pipe insulation for shallow ground source heat pump systems, which had heat transfer rates of more than 120 W/m in 12 h during both heat injection and extraction experiments. The validated three-dimensional CFD model was used to numerically investigate the influence of various structural parameters on the heat transfer efficiency considering the thermal short-circuiting effect. The thermal short-circuiting effect could be alleviated with thicker inner pipe insulation, while the decreasing annular space occupied by the insulation would reduce the borehole heat transfer rates, thus, an inner pipe with a 35 mm-thick insulation obtained the optimal heat transfer rate. The inner pipe diameter increase contributed to a more severe thermal short-circuiting and poor heat transfer performance. Increasing the outer pipe diameter improved the heat transfer efficiency and an optimal outer pipe diameter of 155 mm existed when considering the heat transfer performance and its efficiency. Therefore, increasing the inner pipe insulation thickness and outer pipe diameters can be regarded as an efficient method to improve the thermal performance of coaxial GHEs.

A triboelectric nanogenerator based on flexible zwitterionic ionic conductive hydrogel for running training monitoring

Recently, wearable electronic devices based on ionic conductive hydrogel have received much attention. However, the hydrogels currently reported face challenges in terms of fatigue strength and mechanical properties. Hence, we designed a flexible zwitterionic ionic conductive (F–Zn) hydrogel for the strain sensor and triboelectric nanogenerator (F-TENG). According to the results, the open-circuit voltage (Voc) of F-TENG can reach 245.54 V. The short-circuit current (Isc) and transfer charge (Qsc) of F-TENG can arrive at 9.16 µA and 81.16 nC. As the self-powered pressure sensor, two linear sensing regions of F-TENG can be observed, with sensing sensitivities of 5.9 kPa−1 and 2.05 kPa−1, respectively. In the meantime, when the F-Zn hydrogel serves as strain sensor, the Gauge Factor (GF) can arrive at 0.99. It's important to note that F-TENG can complement the static sensing of the F-Zn hydrogel strain sensor by having application value in dynamic motion sensing. Comprehensive monitoring of running movements is achievable by two sensors with different working mechanisms, paving the way for multifunctional running hydrogel sensors.

Ultra-stretchable and anti-freezing ionic conductive hydrogels as high performance strain sensors and flexible triboelectric nanogenerator in extreme environments

Conductive hydrogels have shown promising applications in a variety of portable smart wearable electronics and flexible sensors due to their high flexibility, stretchability, adjustable mechanical properties and excellent electrical conductivity. However, most of the current hydrogel-based flexible strain sensors and portable triboelectric nanogenerator (TENG) generally suffer from low stretchability/flexibility, poor mechanical properties, weak low-temperature tolerance and low power output. Herein, a multifunctional ionic conductive hydrogel (PPAVC-BA) with ultra-stretchability (∼1750%), high transparency (85%), high electrical conductivity (13.7 mS/cm), and outstanding anti-freezing properties (below −80°C without freezing). The strain sensor assembled from the PPAVC-BA hydrogel shows high sensitivity (GF=4.43) and ultra-wide sensing detection range (0%-1100%) as well as fast response time. Based on these properties, the PPAVC-BA hydrogel strain sensor can accurately recognize different joint movements of the human body as well as weak muscle beats. In addition, the PPAVC-BA hydrogel-based TENG (PPAVC-BA-TENG) exhibits excellent electrical output performance, with an open circuit voltage (Voc) of about 420 V, a short circuit current (Isc) of 23 μA, a short-circuit transfer charge (Qsc) of 112 nC and a maximum power density of 2246.03 mW/m2, which allows it to power small electronic devices. This PPAVC-BA-TENG also shows outstanding tensile performance and can output stable electrical signals at 200% strain. Impressively, the PPAVC-BA-TENG exhibits good electrical output performance even at low temperature of −50°C and high temperature of 80°C. The flexible strain sensors and stretchable TENG for high performance and multifunctionality reported in this work provide viable references in the development of motion detection, energy harvesting and self-powered electronic devices.

Visualization and control of the free-flight transfer phenomenon in the wire feed control process

Gas metal arc (GMA) welding requires improved process stability, higher quality and efficiency, and quantitative control of the heat input and deposition. These requirements can be achieved by appropriately controlling the metal transfer phenomenon. However, this control method has primarily been applied to short-circuit transfer, and very few examples of its application to free-flight transfer exist. Therefore, the effect of wire feed control on free-flight transfer remains unclear. In this study, the influence of wire feed control on the free-flight transfer phenomenon in the GMA welding process using an aluminum wire electrode was investigated through experimental observations, and free-flight transfer control was attempted.It was observed the free-flight transfer phenomenon, particularly globular transfer, under low-current conditions with controlled wire feeding under various feed conditions, using wire feed–retract speeds and cycles as parameters. The observation results revealed two patterns with different timings of droplet detachment under long- and short-period conditions. Furthermore, the observation of the droplet detachment motions revealed that the inertia caused by the acceleration or deceleration of the feed speed acts on the droplet. Moreover, the difference between the two transfer patterns is primarily caused by the inertia acting on the droplet before and after switching the wire feed–retract direction and the size of the droplet at that time. Based on this, free-flight transfer can be stabilized by reconfiguring the feed conditions.

Evolution of Advanced Process Control in GMAW: Innovations, Implications, and Application

The first half of this paper reviews the significant body of work that has been devoted to understanding the fundamentals of the basic GMAW process and the use of this knowledge to develop and enhance process performance. Some of the important background studies devoted to metal transfer mechanisms are reviewed, and the tools developed to model the process and define the critical control variables for GMAW are discussed. The limitations in process performance, such as unstable transfer in low current globular, spray, and short circuit transfer modes and the perceived risk of lack of fusion in short circuit transfer, are considered. These limitations have been mitigated to some extent by process optimization based on the process models developed as well as improvements in welding consumables. Despite the limitations, it is suggested that satisfactory operation could be achieved with simple equipment and a limited number of essential control variables. Early attempts to rectify the limitations are described, but it is argued that these early innovations were restricted by the limited operating envelopes and capabilities of the original power supplies. The radical development of advanced electronic power control and its effect on extending the process operating modes is described, as are the developments in dynamic waveform control. The introduction of synergic control to enable the more complex control variables to be accommodated is also discussed. The effect of waveform control and synergic program constraints on welding procedure management is analyzed, and the advantages of improved process monitoring are reviewed. Future developments in process monitoring and control based on artificial intelligence are introduced, and a possible development to improve synergic program flexibility is suggested. Finally, the type of applications that fully utilize this ‘intelligent’ GMAW are illustrated.

Stability Analysis of Metal Active-Gas Welding Short-Circuiting Transfer Based on Input Pulsating Energy.

In this study, a platform for a welding experiment, used to collect input and output electrical signals, was constructed, and the algorithm for the input pulsating energy interpolation line (IPEI) was given. Experiments with MAG surface straight line welding were conducted at various voltages. Analysis of the IPEI in relation to the welding current was performed while combining real-world welding occurrences with high-speed camera images of droplet transfer. It was established that the IPEI can be employed as a characteristic parameter to assess the stability of the short-circuiting transfer process in MAG welding. The three criteria for assessing the stability were the spectrum, approximation entropy, and coefficient of variation. A comparative analysis was conducted on each of these approaches. It was determined that the most effective technique is approximation entropy. The approximation entropy of the welding current and IPEI are also highly consistent, with a correlation coefficient as high as 0.9889.

A multifunctional hydrogel-based strain sensor and triboelectric nanogenerator for running monitoring and energy harvesting

Recently, flexible wearable electronics for human running posture monitoring and human energy harvesting have attracted widespread attention. Hence, we design a mixed type conductive hydrogel based on polyvinyl alcohol, cotton paper, graphite oxide, and MXene, named PCGM hydrogel. Furthermore, the PCGM hydrogel can act as the PCGM-based strain sensor and triboelectric nanogenerator (P-TENG) for running posture monitoring and mechanical energy harvesting. The PCGM-based strain sensor has two sensing linear regions: The pressure sensitivity is 0.0164 kPa−1 in the low pressure region (0–16 kPa), whereas it is 0.002 86 kPa−1 in the high pressure region (16–120 kPa). To achieve comprehensive health monitoring of runners, the PCGM-based strain sensors can be installed on human joints and facial skin to monitor human posture and facial expressions. The PCGM hydrogel can be combined with a polytetrafluoroethylene film to form a P-TENG device for mechanical energy harvesting. The P-TENG maximum output power can reach 135 µW with a 30 MΩ load. The short-circuit current (Isc), open-circuit voltage (Voc), and transfer charge (Qsc) of P-TENG can reach 10.36 µA, 229.85 V, and 49.24 nC, respectively. This research provides an effective approach for human-running motion monitoring by using multifunctional flexible devices.

Key mechanism of metal transfer and characteristic of cavity evolution during SAW using in-situ X-ray imaging method

The metal distribution and transfer during submerged arc welding (SAW) were investigated using in situ X-ray high-speed imaging method. The flux-wall droplet transfer mode was observed for the first time in SAW using a 1.6 mm diameter 308 L wire and the repelled droplet transfer mode and short circuit droplet transfer mode are also confirmed as the three fundamental modes. As the unique forces in the SAW, the supporting force and viscous resistance by the flux wall to the droplet affect the droplet geometry feature and transfer mode. These two forces are determined by the geometrical morphology of the cavity. As the welding speed increases from 1.5 mm/s to 4 mm/s, the proportion of short circuit transfer mode decreased from 70.69% to 3.64% while the repelled droplet transfer mode increased from 3.45% to 96.36% due to the reduction of cavity volume. The proportion of flux-wall transfer mode initially increased and then decreased. It reached the highest as the vertical cavity formed at the welding speed of 2 mm/s. Once the welding speed exceeds 4 mm/s, the flux-cored droplet transfer mode disappeared. The proportion of the other two tends to be stable because of an almost unchanged cavity volume.

Characterization of cold metal transfer and conventional short-circuit gas metal arc welding processes for depositing tungsten carbide-reinforced metal matrix composite overlays

This paper compares the processing characteristics of advanced CMT (cold metal transfer) and conventional GMAW-S (gas metal arc welding with short-circuit metal transfer) processes for depositing Ni-WC MMC (nickel-based metal matrix composites reinforced with WC) overlays. In contrast to common expectations, advanced CMT technology with mechanically assisted droplet transfer could not demonstrate significant advantages over the GMAW-S process; on the contrary, CMT exhibits marginal disadvantages in terms of carbide transfer efficiency, volume fraction of retained WC, and deposition rate. Some carbides originally contained in the core of the feed wire are blown away and expelled out of the processing zone leading to physical losses of WC particles during the deposition processes, which is more significant for the CMT process owing to much higher waveform cycle frequency and cyclic feed wire retractions. CMT exhibits superior waveform stability, better control over penetration depth, marginally lower dilution level, and exceptional arc stability. The main parameters affecting carbide transfer efficiency and volume fraction of retained WC are wire feed speed and travel speed for both processes; increased wire feed speed and travel speed generally lead to decreased carbide transfer efficiency and reduced volume fraction of retained WC. Shielding gas may have different effects on the outcomes for the CMT and GMAW-S processes. CMT overlays show comparatively higher W and lower Fe concentration in the matrix, while GMAW-S overlays show a higher concentration of Fe in the matrix (due to elevated dilution level) with marginally higher matrix microhardness and more herringbone-like secondary carbide precipitates.

STUDY OF DROPLET TRANSFER CHARACTERISTICS AND WELD FORMATION WITH ER430LNb FERRITIC STAINLESS STEEL DURING GAS METAL ARC WELDING

An ER430LNb ferritic stainless steel wire was used for a gas metal arc welding (GMAW) test. The characteristics of droplet transfer and its corresponding voltage and current waveforms were investigated using a high-speed camera and synchronous acquisition of electrical signals. The weld formation, droplet transfer patterns and corresponding microstructures under different welding parameters were observed, and the effect of the current level on the droplet transfer frequency was discussed. As the results show, there were three typical metal transfer patterns during the GMAW using the ER430LNb ferritic stainless steel wire, namely short circuit transfer, mix transfer and spray transfer. With an increase in the welding current, the weld formation is changing constantly, and the droplet transfer frequency increases exponentially. With the change in the transfer pattern, the columnar ferrite structure of the weld is continuously coarsening. In addition, hardness measurements were taken on joints welded at different welding currents for comparison.

The influence of bypass current on arc energy density and metal transfer behaviour in bypass current compressed gas metal arc welding

A new welding method, bypass current compressed gas metal arc welding (BCC-GMAW), was developed to enhance the arc energy density and welding stability of GMAW. When the bypass current was applied, the arc energy density was increased with the constraining effect of the circumferential bypass electrode, which was studied by current density and arc pressure, resulting in an increase of 46% in weld depth and a decrease of 38% in weld width. As the coupled arc increased the melting speed of wire and forces of droplet downward transfer, the droplet transfer frequency increased by 185%, and the metal transfer mode was changed from short-circuit transfer to stable small globule transfer, obtaining a smooth and uniform weld appearance.

Deepening the understanding of arc characteristics and metal properties in GMAW-based WAAM with wire retraction via a multi-physics model

Wire retraction is used in the short-circuit droplet transfer mode of gas metal arc welding (GMAW) to improve the stability of transfer, reduce heat input and decrease spatter. The significant effects of wire retraction on the arc plasma characteristics and the thermal properties of the metal are not well understood. In this paper, we develop a three-dimensional, transient, multi-physics coupled GMAW model with wire retraction and apply it to wire arc additive manufacturing (WAAM) of an aluminum alloy. The model takes into account the wire's downward and upward motion, droplet growth and detachment, arc plasma heating, metal vaporization, melting and solidification of the molten pool, and the relative motion of the wire and substrate. The model is used to simulate the deposition of a single layer, and the evolution of the arc characteristics and the metal thermal and flow behavior are analyzed. The results demonstrate that during a wire motion period, the arc characteristics are determined by both the transient welding current and the distance between the welding wire and the molten pool. The arc plasma has a significant influence on the temperature and flow of the droplet and the molten pool metal when the wire is well separated from the melt pool and the welding current is in its peak phase. The energy and momentum of the metal in the molten pool are primarily influenced by the metal transfer, and the maximum flow velocity and maximum temperature occur at the time of the short-circuit contact. The results demonstrate the advantages of using a low welding current during droplet transfer, which is made possible by wire retraction. The model is validated by comparing the predicted morphology of the deposited layer and the shape of the arc during a wire motion period with experimental results, with reasonable agreement found.

On the contact electrification mechanism in semiconductor–semiconductor case by vertical contact-separation triboelectric nanogenerator

With the speed of industrialization accelerating, the traditional energy is in the predicament of being exhausted. Humans urgently need a clean energy to maintain the peace and development. Triboelectric nanogenerator (TENG) is a tiny device that collects and converts the renewable energy, such as wind, vibration and tidal/blue energy, into electrical energy. As the most significant working principle of TENG, contact electrification (CE) has been broadly studied since it was documented thousands of years ago. A large number of related researches are reported. However, most of them are focused on the polymer materials, device structures and potential applications. There are few literatures about the mechanism of CE, especially in the semiconductor–semiconductor case. Semiconductor–semiconductor CE is a promising method to generate electricity, which has been used in many fields, such as the photodetector and displacement sensor. Therefore, it is necessary to establish a serious and detailed theory in order to deeply explain the underlying mechanisms of semiconductor–semiconductor CE. In this work, a novel Fermi level model based on energy band theory is proposed to illustrate the semiconductor–semiconductor CE mechanism. By assembling a ZnO/Si vertical contact-separation (CS) mode TENG, the charge transfer introduced by CE is systematically measured. According to the energy band theory and TENG governing equation, the experimental data is qualitatively and quantitatively analyzed. Moreover, the effects of different concentrations of growth solutions on the morphology of ZnO nanowires and the Fermi level difference between ZnO and Si are explored as well. Results show that it is the Fermi level difference that dominates the short circuit transfer charge amount and direction of semiconductor–semiconductor CE mechanism. Our work can be applied to understand the CE mechanism in semiconductor–semiconductor case and broaden the application prospects of semiconductor-based TENG.

Tensile properties and microstructure of surface tension transfer (STT) arc welded AA 6061-T6 aluminum alloy joints

The wide usage of 6xxx series aluminium alloys in automobile sector is mainly because of the exceptionally good weldability characteristics and better corrosion resistance. Surface tension transfer (STT) arc welding is one of the variants of gas metal arc welding (GMAW) that has potential features such as low heat input and arc stability with an innovative wire feed system. STT is a modified short-circuiting metal transfer technique that regulates the metal transfer rate using a high-frequency inverter power supply This process is widely used in automobile industry due to its higher welding speed and capability to weld thin sheets without defects like spatter, distortion and burn through. This article reports the welding of thin aluminium 6061 sheets by STT arc welding process and presents the tensile properties of the welded joints. The features of the microstructure are characterized by optical microscopy. The fracture surfaces are being examined by scanning electron microscopy. During the tensile test, the welded joint failed at 12 mm from weld zone. It is evident that failure is generated by softening in (heat affected zone) HAZ region due to the production of β′or β precipitates which are softer and incoherent in nature. The tensile properties of STT welded aluminium alloy joints yielded a better joint efficiency of 71.08 % due to the presence of higher hardness in the welded region. The hardness results signify that the HAZ noted low hardness which is called as softened zone, where the transformation of precipitates or coarsening of grains takes place.

Optimization of CMT Characteristic Parameters for Swing Arc Additive Manufacturing of AZ91 Magnesium Alloy Based on Process Stability Analysis.

The droplet transfer behavior and stability of the swing arc additive manufacturing process of AZ91 magnesium alloy based on the cold metal transfer (CMT) technique were studied by analyzing the electrical waveforms and high-speed droplet images as well as the forces on the droplet, and the Vilarinho regularity index for short-circuit transfer (IVSC) based on variation coefficients was used to characterize the stability of the swing arc deposition process. The effect of the CMT characteristic parameters on the process stability was investigated; then, the optimization of the CMT characteristic parameters was realized based on the process stability analysis. The results show that the arc shape changed during the swing arc deposition process; thus, a horizontal component of the arc force was generated, which significantly affected the stability of the droplet transition. The burn phase current I_sc_wait presented a linear function relation with IVSC, while the other three characteristic parameters, i.e., boost phase current I_boost, boost phase duration t_I_boost and short-circuiting current I_sc2, all had a quadratic correlation with IVSC. A relation model of the CMT characteristic parameters and IVSC was established based on the rotatable 3D central composite design; then, the optimization of the CMT characteristic parameters was realized using a multiple-response desirability function approach.

Influence of Ship-based Vibration on Characteristics of Arc and Droplet and Morphology in Wire Arc Additive Manufacturing

To explore the feasibility of using wire arc additive manufacturing (WAAM) for forming and repairing marine components during ship navigation, this study conducted deposition experiments of ER50-6 steel and investigated the interference of ship-based vibrations on the WAAM equipment and influence of the characteristics of the arc droplets and sample morphology. The results revealed that the WAAM equipment vibrated with the external vibrations from the surrounding environment, and the welding gun and base plate produced dissimilar vibrations, which yielded unstable arc shapes resembling a bell, trumpet, fan, broom, and other irregular shapes. The mode of the droplet transfer ranged from the stable spray transfer mode to extensive amounts of large droplet transfer and short-circuit transfer. Although the morphology of the obtained sample deteriorated, the fully dense and defect-free interior demonstrated the applicability of ship-based WAAM.