Wire Feed Speed Research Articles

Investigation on underwater wire-feed laser deposition of 5052 aluminum alloy

The underwater laser deposition layer with uniform forming on the 5052 aluminum alloy was successfully manufacturing by the underwater wire-feed laser deposition (UWLD) technology with a laser deposition (LD) gas-shielding nozzle. Process parameters including deposition speed and wire feed speed were optimized and laser propagation attenuation mechanism, the geometrical characteristics, microstructure and microhardness of deposited track in the in-air and underwater environment were investigated. Increasing deposition speed or reducing wire feed speed, the wetting between the base material and deposited metal improved and a high-quality UWLD layer without defects was obtained at 15 mm/s deposition speed and 1.2 m/min wire feed speed. For UWLD, the laser beam energy decreased owing to absorption and scattering of aerosol particles, causing differences in the geometric features to in-air wire-feed laser deposition (IWLD) and reducing the wettability and fluidity of the deposited metal on the substrate. In both IWLD and UWLD layers, the microstructure of the deposition region (DR) was equiaxial dendrites while the fusion region (FR) was composed of columnar dendrites. The columnar dendrites nucleated at the fusion line and grew along the reverse direction of the temperature gradient to the centerline of the melt pool while the underwater grains were more refined attributed to the greater cooling rate under water, indicating the increase of microhardness.

A machine learning approach for the prediction of melting efficiency in wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) appears as one of the most promising technologies due to its capacity to process all types of materials used in welding, its high production rate, and capacity to process large geometries of particular interest in the aeronautical industry. Since this technology is still under investigation, it is important to determine the efficiency of the process; in this sense, the melting efficiency stands out not only as a parameter of interest in energy terms but also as a measure of the stability of the process. For calculating melting efficiency, it is necessary to use tailored colorimeters or apply models requiring specific dimensions that involve destructive testing. For this reason, in the development of this work, the melting efficiency is evaluated through machine learning algorithms. Processing parameters such as wire diameter, wire feed speed, travel speed, and net power are used to determine melting efficiency. In addition, a simplified analytical model was developed to compare the results. The average melting efficiency analytically calculated was 44.56 ± 5.48%, while the predicted value reaches a comparable value of 44.32 ± 4.79% obtained with the Gaussian process regressor, which shows the highest accuracy. Moreover, the known relationship with travel speed was verified.

Machining of Y2O3 reinforced magnesium rare earth alloys using wire electrical discharge turning process

Advanced machining has become one of the inevitable processes for the fabrication of miniature industrial components that demands high dimensional accuracy. Magnesium (Mg) and its composites have widespread applications in the areas of aerospace, medical, and automobile sectors. The objective of this work is to analyze the machinability of Mg—rare earth (RE) alloy (Mg3Al2.5La)-based nanocomposites using wire electrical discharge turning (WEDT), a variant of EDM process. Y2O3 (0.6 and 1.9%) reinforced magnesium composites are prepared through disintegrated melt deposition technique. SEM and XRD analyses confirmed the intermetallic phase formation, such as Al11La3, and Al2La. Machining experiments are conducted with input parameters: discharge ON time, wire feed and spindle rotational speed each varied at three levels to study surface roughness (Ra) and volume of material removed (MRR). Results showed that Ra of the machined samples increases and MRR decreases, with the increase in % reinforcement and discharge ON time. The lower Ra value of 2.985 µm and higher MRR of 34.85 mm3/min are observed for the Mg3Al2.5La sample. This result is attributed to the absence of particle pullout and increased thermal conductivity of magnesium alloy during machining. Prediction analysis based on mean values is carried out to confirm the accuracy of the experimental results at optimal parametric levels.

Study on droplet transition behavior, bead geometric characteristics and formability of wire + arc additively manufactured Inconel 718 alloy by using CMT MIX+ Synchropulse process

In this paper, the droplet transfer behavior, geometric characteristics of weld bead and formability of CMT MIX + Synchropulse (CSP) wire + arc additively manufactured Inconel 718 alloy under high wire feeding speed are studied. The results show that a CSP cycle is composed of a CSP high-frequency pulse stage (CSP–HFP) and CSP-CMT stage, and the periods ratio is about 1.7:1. The high frequency and large average welding current of CSP-HFP increase the arc force, which further increases the droplet impact force on the molten pool. The molten pool is significantly deformed, resulting in the penetration depth of the CSP weld bead (1.8 mm) apparently higher than that of CMT (0.5 mm). The surface of the CMT-WAAM sample is more rough and irregular. The large penetration depth provides sufficient support for the molten pool, which promotes the overall stability of the molten pool. The increase of the droplet impact and arc forces enhance the convections in the molten pool, which finally suppresses the overflow phenomenon.

Numerical Analysis and Experimental Verification of Resistance Additive Manufacturing

In recent years, scholars have proposed a metal wire forming method based on the Joule heat principle in order to improve the accuracy of additive manufacturing and reduce energy consumption and cost, but it is still in the theoretical stage. In this paper, a mathematical model of resistance additive manufacturing was established using finite element software, and the temperature variation of the melting process under different currents was analyzed. A suitable current range was preliminarily selected, and an experimental system was built. Through experimental study of the current and wire feeding speed, the influences of different process parameters on the forming appearance of the coating were analyzed. The results showed that the forming appearance was the best for Ti-6Al-4V titanium alloy wire with a diameter of 0.8 mm, when the current was 160 A, the voltage was 10 V, the wire feeding speed was 2.4 m/min, the workbench moving speed was 5 mm/s, and the gas flow rate was 0.7 m3/h. Finally, the process parameters were used for continuous single-channel multilayer printing, verified the feasibility of the process at the experimental level and provided reference data for the subsequent development of this technology.

Parametric Optimisation of Micro Plasma Welding for Wire Arc Additive Manufacturing by Response Surface Methodology

High deposition rate with minimal heat input is one of the primary emphases in wire arc additive manufacturing. This study aims to determine the optimal input parameters of micro plasma welding for single-layer deposition. The stability of a single layer is crucial as it serves as the foundation relative to the deposition of layers to avoid a discontinuous multi-layer material. The study focuses on wire feeding speed, welding speed, and pulse and their interaction between the input and response variables. Based on the study, the regression equation between the three key parameters and the response using the Box-Behnken Design response surface methodology was proposed. The outcome demonstrates that the op-timized sample deposition produces a smooth surface appearance with no apparent defects.

Influence of tool path planning on process stability and deposition accuracy in laser material deposition with coaxial wire feed

Laser material deposition (LMD) is a laser-based additive manufacturing process that is widely used for fabrication, diversification, and repair of parts in various industries. LMD processes can be distinguished by the form of the filler material. In terms of availability, storage, safe handling, and price, filler material in wire form often has advantages over powdered materials. In this work, the influence of tool path planning on the deposition accuracy and the process stability of LMD with coaxial wire feed is studied. The laser beam and wire are arranged coaxially to each other, with the wire being fed through the inside of an annular shaped laser beam without any shadowing. While the process is completely directionally independent, the stability is linked to the wire feed rate, laser power, and process feed rate. Additionally, the ratio between the wire and the laser beam diameter affects the stability. Movement of the wire inside the annular beam may result in shadowing and process abort. Changes in the working distance (defocusing) lead to changes in the beam diameter, which affects the process stability. This can result in imperfections, i.e., bonding defects, or pores in the tracks and layers that will add up in the built components and must be avoided for imperfection-free three-dimensional geometries. On even surfaces, the geometry of the deposited tracks is controlled by changing the laser power, the wire feed speed, and the process speed. When building three-dimensional parts, critical points of the tool path planning are acute angled corners and crossing points. In the experiments, boundaries for the process stability in critical points are established and track geometries are compared to previous results. Furthermore, different strategies for the avoidance of material accumulation at the start, end, and crossing points are investigated. The different approaches are discussed, and finally an outlook for further use and possible applications is given.

Optimization of Argon Gas Metal Arc Welding Process Parameters with Regard to Tensile Strength for AISI 310 Stainless Steel Using Taguchi Technique

Gas metal arc welding (GMAW) is the leading process in the development of arc welding process for higher productivity and quality. In this study, the effect of process parameters of argon gas welding on the strength of T type welded joint of AISI 310 stainless steel is analyzed. The Taguchi technique is used to develop the experimental matrix and tensile strength of the welded joint is measured using experimental method and finite element method. Optimization of input parameter is performed for the maximum tensile strength of welded joint using ANOVA. The results showed that welding speed is the most significant factor affecting the tensile strength followed by voltage in argon gas metal arc welding (AGMAW) process. Argon gas welding process performance with regard to the tensile strength is optimized at voltage: 18.5 V, wire feed speed: 63 m/min and welding speed: 0.36 m/min.

Effect of the current waveform on the droplet transfer in CMT welding high-nitrogen steel

During the welding process of high-nitrogen steel, droplet bursts often occurs, which is caused by the escape of nitrogen. To analyze the influence of the current waveform on the cold metal transfer (CMT) welding process of high-nitrogen steel, a high-speed camera and current and voltage sensors were used to establish a simultaneous acquisition system for droplet transfer visualization and electrical parameter waveform monitoring. In this way, the characteristics of the droplet transfer behavior of the high-nitrogen steel CMT welding process were analyzed. The results showed that the solubility of nitrogen in the droplet decreased as the energy input rose, causing nitrogen to escape in the form of bubbles. When the pressure difference inside and outside of the droplet was greater than the surface tension, droplet cracking occurred. In the CMT welding process of high-nitrogen steel, the peak stage of the current waveform had a relatively high influence on droplet transfer. The condition of stable droplet transfer was that the peak phase current was 100–150 A, the time was 4.55–6 ms, and the maximum energy input in the peak stage was 15.5 J per CMT cycle. The current in the waiting phase, which was under 100 A, did not affect the droplet transfer behavior but did affect the shape of the molten pool. The increase in the peak wire feed speed reduced the CMT cycle time, but had little effect on droplet transfer.

Optimization of the mechanism welding mode in a shielding gases environment of shell structures in the position “on weight”

Due to their simplified spatial shape, shell cylindrical designs have acceptable manufacturability. The latter makes it possible to use a variety of fusion welding methods in their manufacture, including the option of mechanized welding in protective gas environments. Such a technological process is considered to be sufficiently developed in terms of theory and application, as evidenced by specialized equipment for it and numerous recommendations for the selection of installation and running welding parameters. Analysis of such material demonstrates that the basic technology is welding in the lower position with a seam root lining or with the use of a suitable technological arrangement for rotating large structures to provide such conditions. Much more difficult to meet the quality requirements for a welded joint are repair and welding works of non-rotating structures with a one-sided approach to the welding zone and the absence of a seam root lining. In this case, welding equipment with electric or electric-mechanical control of the process of dropwise transfer of metal into the bath is used, regardless of the spatial position of the seam. However, in cases of single production or repair welding, classical welding sources are still widely used, in which the regulatory requirements for the weld are provided by its appropriate external characteristics, the effect of self-regulation of the arc and dynamic characteristics. Here, the variant of droplet transfer with a short circuit of the droplet to the bath is typical, with the characteristic instability of energy accumulation / return of the source choke at the stages of the arc and droplet and the corresponding behavior of the arc in different spatial positions. Since the parameters of the mode are interdependent and, thus, welding itself represents a poorly organized system that has a variety of physical parameters that cause different in nature, but tightly interconnected processes in the zone of weld formation. The best tool for assessing the condition and regulation of such a system today is planning an experiment with independent controlled (setting) parameters of the welding mode and quality feedback – the optimized amount of weld penetration. On the basis of the processing of the array of recommended data regarding the selection of the value of the setting parameters of the welding process by the procedure of constructing symmetric histograms and the distribution polygon and calculating the analytical model of the description of the distribution density for each setting parameter of the process, their average values are set with a probability of 0.9. The latter were used to calculate the actual values of the following parameters for welding a given material thickness – electrode wire diameter 1.6 mm, welding current 190 A, voltage 25±1 V, welding speed – 26–42 m/h, wire feed speed 21–29 m/h, electrode discharge wire 16 mm. On the basis of the specified reference base of parameter values, a planned experiment was set up and implemented to find the optimum on a matrix of a composite symmetrical three-level plan, as variable factors are set – process voltage, welding wire feed speed and welding speed; the height of penetration of the assembled parts is set by the response. The region of the optimum and the influence of the setting parameters of the mode on it, as well as the analysis of its response surfaces and cross sections of such surfaces demonstrate that the setting parameter – the source voltage should practically be constant at the level of 24 V and does not have a significant adjustment ability for the correction of the welding mode. The setting kinematic parameters of the mode are the wire feed speed and the welding speed, respectively 23 and 27 m/h, at the given arc voltage, they provide welding in one pass. In terms of the depth of the ability to adjust the quality of the seam formation, the welding speed prevails, since, all other things being equal, the wire feed speed is strictly correlated with the speed of its melting at a given diameter and electrode distance. The latter determine the actual value of the current, the value of which is limited by the source voltage, which is strictly specified and constant for the given process under study.

Effects of deposition parameters on cumulative energy demand for Cold Metal Transfer additive manufacturing processes

This paper proposes a methodology that can be used to assess the effects of variations in the process parameters on the energy consumption of a Cold Metal Transfer (CMT) additive manufacturing process. The analysis was carried out at the process level and then extended to cradle-to-gate system boundaries. A thin-walled component was considered as a demonstrative case study. The results demonstrate that any variation in deposition process parameters (namely, the wire feed speed and the travel speed) affects not only the energy requirements related to the deposition process itself, but also the material deposition efficiency and the cradle-to-gate cumulative energy demand.

Dependence of process planning strategy on deposition ratio in wire arc additive manufacturing

Metal parts are manufactured using various metal additive manufacturing processes. Wire arc additive manufacturing (WAAM) is the process that uses an arc as a heat source and feeding material in the form of wire. The existing WAAM process has limitations in producing metal components with high geometrical accuracy. In this study, ER70S6 wire was used for developing a unique process-planning method based on deposition ratio (DR) to minimize the complexity of the process in achieving high geometrical accuracy. Weld bead geometry is determined by measuring the width and height of the deposited beads. By varying the travel speed (TS) keeping the wire feed speed (WFS) constant the process depends on the deposition ratio is studied. The result justified the direct proportionality between the deposition ratio and the bead height. Hence, this indicates that this procedure is effective in producing a high-quality deposited bead profile just by controlling the deposition rate.

Development of WEDM Simulation with Parameters Adaptively Changed using Wire Electrode Displacement Sensor

During wire electrical discharge machining (WEDM), various forces like discharge reaction force, electrostatic force, electromagnetic force, and drag force due to fluid flow cause vibration and deflection of the wire electrode. The generated vibration and deflection of the wire electrode exert a large impact on machining accuracy. Therefore, to achieve higher machining accuracy, a WEDM simulation was developed to calculate the behaviors of the wire electrode during machining to obtain the workpiece shape. In the simulation, parameters which are difficult to measure directly, such as the discharge reaction force and drag force, were obtained from the inverse problem method so that the vibration and deflection of the wire electrode measured using an optical sensor coincided with the calculated ones in the simulation. Since these parameters may change during machining even under the same discharge pulse conditions depending on the cutting depth, workpiece thickness, and curvature of the machining path, the parameters should be changed adaptively based on the wire behaviors measured in the process. In this study, the WEDM simulation with parameters adaptively changed was applied to the machining of a stepped workpiece and the accuracy of the simulation was evaluated. Although there were certain errors in the kerf width and wire feed speed between the simulation and real machining, the changes in the kerf width and feed speed could be reproduced qualitatively. The necessary to improve the simulation strategies was discussed to realize higher accuracy.

Parametric study and optimization of GMAW based AM process for Multi-layer bead deposition

Wire arc additive manufacturing (WAAM) is popularly becoming an important and cost-effective manufacturing process to fabricate medium-large size components. The process provides the ability to build a near-net-shape structure with a high production rate (50–130 gm/min) and high material usage efficiency (80–90%). However, as per other additive manufacturing (AM) processes, process planning and optimization provide a uniform, time-efficient, and defect-free deposition. Therefore, this study focuses on the parametric study and process optimization to fabricate multi-layers wall components. The most commonly and widely used SS304 stainless steel metallic wire has been used to fabricate four-layered wall structures using multi-layer bead deposition. Open circuit voltage (OCV); wire feed speed (WFR) and shielding gas flow rate (SGFR) has been selected as the input process parameters and the bead height to width ratio (H/W) selected as the output parameter. The nine experiments were performed using the L9 orthogonal array based on the Taguchi method and then implemented the analysis of variance (ANOVA) to describe various properties. The resultant data has been analyzed and studied using Minitab-17 software. The results obtained showed that the optimum condition for the H/W ratio is 24 V OCV, 14 m/min WFR, and 10Lit/min SGFR. The order of process parameters influencing the H/W ratio is OCV, WFR, and SGFR. These results were validated by conducting confirmation experiments and found satisfactory.

Prediction of bead geometry on filling cavities in hydroelectric turbine blades by means of robotic welding

This paper presents a methodology of mapping the bead geometry, deposited on a fillet like joint, as a function of the input parameters of the synergic pulsed gas metal arc welding process and the welding position, to allow the planning of repairing hydroelectric turbine runner blades by means of robotic welding. The challenges of automating the repair process; further, to choosing the best welding parameters, include the definition of the path that the robot must follow during the metal deposition, such that it is able to fill completely the damaged blade cavity, by means of producing overlapped layers from several individual weld beads. Thus, this research focused on developing statistical prediction models that could map the geometric variations of the weld bead section as function of the input parameters (wire feed speed, welding speed and bead face rotation angle). For this purpose, the bead section was approximated by a parallelogram whose height, width and inclination angle were considered as dependent variables. Several welding trials were carried out according to a central composite experimental design and three multiple regression models were obtained. Here, the physics is used to interpret the influence of the input parameters on the output results.

Comparative Study Regarding the Welding Behavior of Galvanized Steel Using Laser Welding and Gas Metal Arc Welding Processes

Gas metal arc welding (GMAW) and laser welding are two commonly used joining methods. In this study, these two welding methods were used to join the galvanized sheets. For GMAW, the process parameters were: welding wire diameter, shielding gas flow, welding speed, current and wire feed speed. In term of laser welding, the analyzed parameters were: welding speed, power and pulse duration. In order to establish the effects of the main parameters on the resistance of the welded joint, changes were made to the values ​​of a single process parameter, and the others were kept constant. The combined welded samples were examined non-destructively using X-rays method and then were subjected to destructive tensile tests, analyzing the tensile strength values.

Effect of wire feeding speed on dissimilar laser welding of NiTi shape memory alloy and 2A12 aluminum alloy

Laser welding of NiTi shape memory alloy (SMA) and 2A12 aluminum alloy was realized by using a TC4 wire. Due to the poor metallurgical compatibility of Ti and Al elements, the surface appearance of welded joints was uneven and fluctuated. No obvious cracks were found on the surface. When the wire feeding speed increased to 280 cm/min, the pores at the interface disappeared. There were mainly a fusion zone (FZ), the NiTi SMA/FZ interface, and the 2A12 aluminum alloy/FZ interface in the welded joints. Some dendritic microstructures grew vertically toward the FZ at the NiTi SMA/FZ interface. The distance grown of the microstructure at the interface reduced while the wire feeding speed increased. Due to the increase of wire feeding speed and the decrease of the heat input per unit volume, the ability of the atoms to diffuse and migrate reduced and the trend grown of the microstructure was inhibited. For the FZ, there were α-Ti + β-Ti + Ti2Ni phases. The difficulty of decomposition for the β-Ti phase increased because the molten pool contained a large amount of the Ni elements and a small amount of Fe and V elements. After the molten pool cooled, there would be the β-Ti phase in the FZ. With the increase of wire feeding speed, the intermetallic compounds changed from Ni–Ti to Al–Ti. Besides, the fracture load of welded joints first increased and then decreased. When the wire feeding speed was 280 cm/min, the maximum fracture load of the welded joint was 176 N/mm and the fracture mode of the joint was an intergranular brittle fracture.

Laser hot-wire cladding of Ni/WC composite coatings with a tubular cored wire

Ni/WC composite coatings were successfully prepared on carbon steel by the method of laser hot-wire cladding with a tubular cored wire. The processing characteristics, phases compositions, microstructural evolution, and wear resistance of the coatings were systematically investigated. A high-speed camera was used to investigate the wire transfer behaviors under various processing parameters which included the laser power of 1000 W, wire feeding speed of 4 mm/s, laser scanning speed of 2 mm/s, and different preheating currents (0∼100A). Three typical wire transfer modes including wire stubbing transfer (0∼50A), wire plunging transfer (55∼80A), and wire fusing transfer mode (90∼100A) were obtained. The coating microstructure was mainly consisted of the retained particles, Ni-dendrites, Ni/Ni3B eutectic structure, and various kinds of precipitations including WC, W2C and M6C (M = Fe, Ni, W) carbides. It was found that the wire transfer mode was a critical factor of influencing the geometrical and microstructural characteristics of the coatings. The WC particles could be generated in the coatings when the lower dilution degree (0.8∼1.2 %) was obtained under the wire stubbing transfer mode. When the wire plunging transfer was produced as the total energy input was increased, the homogeneously distributed W2C particles could preferentially be precipitated in the coatings with a relatively low dilution (1.9∼7.9 %). The M6C carbides were mainly formed in the coatings with a high dilution ratio (12.1∼13.9 %) fabricated under the wire fusing transfer mode. The coatings fabricated under wire plunging transfer mode exhibited higher wear resistance which was about 31∼51 times higher than that of substrate.

Transferability of the working envelope approach for parameter selection and optimization in thin wall WAAM

This work aims to propose and assess a methodology for parameterization for WAAM of thin walls based on a previously existing working envelope built for a basic material (parameter transferability). This work also aimed at investigating whether the working envelope approach can be used to optimize the parameterization for a target wall width in terms of arc energy (which governs microstructure and microhardness), surface finish and active deposition time. To reach the main objective, first, a reference working envelope was developed through a series of deposited walls with a plain C-Mn steel wire. Wire feed speed (WFS) and travel speed (TS) were treated as independent variables, while the geometric wall features were considered dependent variables. After validation, three combinations of WFS and TS capable of achieving the same effective wall width were deposited with a 2.25Cr-1Mo steel wire. To evaluate the parameter transferability between the two materials, the geometric features of these walls were measured and compared with the predicted values. The results showed minor deviations between the predicted and measured values. As a result, WAAM parameter selection for another material showed to be feasible after only fewer experiments (shorter time and lower resource consumption) from a working envelope previously developed. The usage of the approach to optimize parameterization was also demonstrated. For this case, lower values of WFS and TS were capable of achieving a better surface finish. However, higher WFS and TS are advantageous in terms of production time. As long as the same wall width is maintained, variations in WFS and TS do not significantly affect microstructure and microhardness.

Study on Medium-Thick Al-Alloy T-Joints by Dual P-GMAW Bilateral Synchronous Welding

The T-joints of medium-thick 6082 Al-alloy plates created by dual pulsed gas metal arc welding (P-GMAW) and bilateral synchronous welding were investigated to improve weld quality using the adaptive deposition method, which calculates the minimum amount of deposition according to the welding condition, groove size, and cross-sectional area, effectively reducing the heat input and deformation of the welds on the basis of weld filling. The optimized linear energy with a wire feed speed (WFS) of 9.5 m/min can ensure a well-formed weld with a complete root fusion, and high-quality T-joint welds were obtained both in root openings of 0 mm and 1 mm. The biggest penetration was 4 mm, which was four times more than that of the result from a single torch welding process. When the distance between the two welding torches exceeded 20 mm, the molten pool was completely separated, and process pores were observed in the unfused root zone. Influenced by the thermal cycles in asymmetric welding, the hardness distribution changed: the width of the softer zone at the base plate with the fore arc was smaller than that zone with the rear arc. Furthermore, dual P-GMAW bilateral synchronous welding with an asymmetric heat source can further reduce the deformation of the welded joint by about 20% compared to that of symmetric welding.