Wire Feed Speed Research Articles

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.

The effect of WAAM process parameters on process conditions and production metrics in the fabrication of single-pass multi-layer wall artifacts

The present work seeks to understand the impact of varying dwell time and input deposition power on part quality and overall production time for wire arc additive manufacturing. In this work, multi-layer wall geometries were deposited under different input power conditions without affecting the material deposition rate by setting traverse speed and wire feed speed constant and varying the contact tip-to-workpiece distance and the deposition power settings. Current and voltage data and optical imaging of the deposition zone were captured in situ, and wall geometry was characterized using laser scanning, so to understand the applicability of these methods for determining part height in situ. The present results demonstrate that alternating dwell times with lower input deposition power can result in significantly reduced overall production time and minimal material underbuilding, despite increased deposition geometry width. Furthermore, it is shown that while elimination of process dwell results in severe underbuilding of the deposition, it also yields the highest production rate for a hybrid-finished (e.g., deposited, machined) wall in terms of mm in build direction per minute and the highest buy-to-fly ratio.

Microstructure investigation and fracture mechanism of TC4−304L dissimilar joints fabricated by the cold metal transfer arc-brazing method

Wire feeding speeds of 3.5, 4.5, and 5.5 m/min are operated to arc-braze TC4 titanium alloy to 304 L stainless steel with the cold metal transfer method and CuNi filler wire. The microstructure and fracture behavior of TC4−304Ldissimilar joints were characterized by transition electron microscopy (TEM), selected area electron diffraction (SAED) patterns and X-ray microscope (XRM). The results show that the TC4/seam transition zone consists of an inner Ti-rich layer and an outer Ti-poor layer based on the line scanning result, which contains complex eutectic microstructures such as (Cu, Ni)Ti3, CuNiTi2, CuNiTi, (CuxNi1-x)Ti, and (Cu) solid solutions. The microstructure of the 304 L/seam interface consists of CuNi2Ti, (Cu, Ni) and (Fe, Ni) solid solutions. With increasing heat input, the thickness of the TC4/seam transition zone and the size of (Fe, Ni) dendrite grains increase, the ultimate tensile strength decreases from 350.8 to 230.5 MPa, and all samples fracture near TC4 side based on tensile samples and XRM results. The crack propagation is due to both the thickness of TC4/seam transition zone and a large amount of brittle CuNiTi equiaxial dendrite grains with a high hardness of 10.4 GPa.

Molten Pool Behaviors in Double-Sided Pulsed GMAW of T-Joint: A Numerical Study

The T-joint is one of the essential types of joints in aluminum welded structures. Double-sided welding is a preferable solution to maintain high efficiency and avoid significant distortion during T-joint welding. However, interactions between double-sided molten pools make flow behaviors complicated during welding. Numerical simulations regarding molten pool behaviors were conducted in this research to understand the complex flow phenomenon. The influences of wire feed rates and torch distances were simulated and discussed. The results show that droplet impinging drives the fluid to flow down to the root and form a frontward vortex. Marangoni stress forces the fluid to form an outward vortex near the molten pool boundary and flatten the concave-shaped molten pool surface. With an increased wire feed speed, the volume of the molten pool increases, and the root fusion is improved. With an increased torch distance, the width of the front molten pool decreases while the length increases, and the rear molten pool size decreases slightly. Both wire feed speeds and the torch distances have limited influences on the basic flow characteristics.

Effect of fabrication parameters on the microstructure and mechanical properties of wire arc additive manufactured AZ61 alloy

The wire arc additive manufacturing (WAAM) was employed to fabricate the AZ61 alloys via different fabrication parameters. The microstructure, including grain size and porosity, varies with the processing conditions, which significantly influence the mechanical properties of the fabricated materials. The superior microstructure with fine grains and reduced porosity was achieved via fabrication parameters with current of 130A, voltage of 12.5 kV and wire feed speed of 820 mm/min, providing exceptionally excellent comprehensive mechanical properties.

Синтез математичної моделі з нечіткою логікою для адаптивного управління процесом MIG/MAG наплавлення

A functional transformer with fuzzy logic is synthesized, which allows to get the estimations of weld beads height and width at the arbitrary values of entry parameters: wire feed speed and torch transverse oscillations amplitude. The influence of these input parameters on the base metal penetration and beads geometric parameters, welded using MIG/MAG process, were studied. Surfacing was performed by a robotic system with an arc power supply "Fronius TPS- 320i", which operated in the mode of arc process synergetic control. The formation of both individual beads and surfacing layers at different overlap coefficients has been studied. The arc surfacing process was realized in a mixture of protective gases (Ar+18%CO2) using a welding wire Св-08Г2С with a 1.0 mm diameter. Surfacing speed – 4 mm/s, frequency of welding torch oscillations – 1 Hz. The obtained experimental dependences of beads width and height, as well as the length of the welding pool can be used in both: creating of multi-pass MIG/MAG surfacing program for robotic restoration of critical purposes parts surfaces, and in preparing of FEM model of MIG/MAG surfacing.

Comparison of Properties and Bead Geometry in MIG and CMT Single Layer Samples for WAAM Applications

The process of Wire Arc Additive Manufacturing (WAAM) utilizes arc welding technology to fabricate metallic components by depositing material in a selective layered fashion. Several welding processes exist that can achieve this layered deposition strategy. Gas Metal Arc Welding (GMAW) derived processes are commonly favored for their high deposition rates (1–4 kg/h) and minimal torch reorientation required during deposition. A range of GMAW processes are available; all of which have different material transfer modes and thermal energy input ranges and the resultant metallic structures formed from these processes can vary in their mechanical properties and morphology. This work will investigate single-layer deposition and vary the process parameters and process mode to observe responses in mechanical properties, bead geometry and deposition rate. The process modes selected for this study were GMAW derived process of Metal Inert Gas (MIG) and Cold Metal Transfer (CMT). Characterization of parameter sets revealed relationships between torch travel speeds, wire feed speeds and the specimen properties and proportions. Differences were observed in the cross-sectional bead geometry and deposition rates when comparing MIG and CMT samples though the influence of process mode on mechanical properties was less significant compared to process parameter selection.

Prediction of bead geometry with consideration of interlayer temperature effect for CMT-based wire-arc additive manufacturing

Cold metal transfer (CMT)–based wire-arc additive manufacturing (WAAM) is increasingly popular for the production of large and complex metallic components due to its high deposition rate, low heat input, and excellent material efficiency. The accurate prediction of the bead geometry is of great importance to enhance the stability of the process and its dimensional accuracy. Besides the wire feed speed (WFS) and travel speed (TS), the interlayer temperature is another key factor in determining the bead geometry because of the heat accumulation in the multilayer deposition. In this paper, considering the varying interlayer temperature, WFS, and TS as inputs, an artificial neural network (ANN) is developed to predict the bead width, height, and contact angle; then, by connecting the ANN model with a bead geometric model, a combined model is established to improve the ANN model. Based on experimental test data, with random combinations of input parameters, the combined model is demonstrated to be able to accurately predict the bead geometry (mean error < 5.1%). The general effect of interlayer temperature on the bead geometry was also investigated by experiment.

Metal transfer behaviour of CMT-based step-over deposition in fabricating slant features

The metal transfer behaviour of slant feature of thin-walls fabricated by cold metal transfer (CMT) process in step-over deposition mode was observed by high speed camera. A slanted short circuiting transfer (SSCT) was generated during deposition and then analysed by asymmetrical magnetic and force model, complicating metal transfer behaviour in comparison with conventional deposition process. The SSCT allowed the droplet to transfer obliquely into the molten pool on previous layer, owing to the pushing force generated by unevenly distributed electromagnetic field in asymmetrical deposition model. The surface tension between wire and liquid metal is the most important force that retarded droplet transfer. The retraction force and electromagnetic force are the main forces to promote droplet transition. The positive forces that promote droplet transfer process can be arranged as Fem > Fr > Fg. The wall width was mainly affected by wire feed speed and the inclined angle can be significantly increased with increasing step-over distance.

Control of forming process of truss structure based on cold metal transition technology

PurposeThe purpose of this paper is to study the wire and arc additive manufacturing (WAAM) method and path planning algorithm of truss structure parts, to realize the collision-free rapid prototyping of truss structures with complex characteristics.Design/methodology/approachFirst, a point-by-point stacking strategy is proposed based on the spot-welding mode of cold metal transfer welding technology. A force analysis model of the droplet is established, which can be used to adjust the posture of the welding torch and solve the collapse problem in the WAAM process of the truss structure. The collision detection model is developed to calculate the interference size between the truss structure and the welding torch, which is used to control the offset of the welding torch. Finally, the ant colony algorithm has been used to optimize the moving path of welding torch between truss with considering the algorithm efficiency and collision avoiding and the efficiency of the algorithm is improved by discretizing the three-dimensional workspace.FindingsA series of experiments were conducted to prove the validity of the proposed methods. The results show that the wire feeding speed, welding speed are the important parameters for controlling the WAAM process of truss parts. The inclination angle of the welding torch has an important influence on the forming quality of the truss.Originality/valueThe force analysis model of truss structure in the WAAM process is established to ensure the forming quality and a collision-free path planning algorithm is proposed to improve forming efficiency.

Numerical study of the thermo-fluid flow and weld appearance of 2195 Al-Li alloys in wire feed laser welding

The wire feed laser welding has significant merits in metal joining technology for the manufacturing industry, which including high energy efficiency, high welding speed, automated workflow and narrow heat-affected zone. During to the interaction between weld pool and welding wire, the welding process is more complicated. In this work, a numerical model to the wire feed laser welding for the liquid bridge transition was built. By constructing a movable welding wire entity accurately, the simulation result for flow and heat transfer inside weld pool and welding wire were acquired by the numerical solution. The temperature field, velocity field and weld appearance can be obtained by simulation results. The results shown that the rapid wire feed speed will increase the heat absorption of welding wire, which can improve the hardness due to higher cooling rate. Through the analysis of experimental and simulation results, the quantitative relationship between weld parameters and weld result can be obtained. The numerical simulation can guide the optimization of welding parameters and control the weld appearance.

Modeling of additive height and numerical analysis of cooling parameters for aero blade remanufacturing

Abstract. Additive remanufacturing height and matching cooling parameters are the key factors affecting blade repair quality. First, the mathematical model of the single additive remanufacturing repair height and wire-feeding speed was established, the solution method was proposed and the numerical solution was obtained, and the validity of the model was verified by experiments. Then, based on the calculation results of a single additive remanufacturing repair, the geometric morphology of the cross section under double additive remanufacturing repair was analyzed, and the mathematical model was established. Second, based on the optimal parameters obtained by numerical analysis and the mathematical model, the fluid structure coupling heat transfer model of “blade fixture” for base channel cooling was established. The cooling effect of the typical section under different initial temperatures and different flow rates was calculated, and the coupled heat transfer in the process of blade remanufacturing was explained by the mechanism. Third, through the comparative analysis of the cooling effect, optimal cooling parameters of double additive remanufacturing repair were obtained, and the model of coupled heat flow was verified by experiment. The results showed that the mathematical model of additive remanufacturing height is effective for studying the thermal cycle and cooling effect of welding, and the cooling parameters obtained by numerical analysis can effectively guarantee the quality of double additive remanufacturing of blade repair.

Effect of ER5356 Welding Wire on Microstructure and Mechanical Properties of 5083 Aluminum Alloy GTAW Welded Joint

Automatic gas tungsten arc welding experiments of 5083 aluminum alloy were completed, to analyze the weld microstructure and mechanical properties. The influences of welding current, travel speed, frequency, and arc length on weld forming and mechanical properties were studied. When the welding current was 160 A, the travel speed was 380 mm/min, the frequency was 100 Hz, the arc length was 4 mm, and the maximum tensile strength of the welded joint was 296.9 MPa, which was 86.8% of the base metal’s tensile strength. The fracture elongation was 7.8%. No porosity was formed in the weld, but there were poor fusion problems. ER5356 welding wire can improve the problem of poor weld fusion and accommodate Mg element vaporization losses. When the wire feeding speed was 1200 mm/min, the tensile strength of the welded joint can be improved to 315.2 MPa, which was 92.2% of the base material’s tensile strength, and the fracture elongation was 8.5%. The tensile specimens fractured in the heat-affected zone. The fracture surface was characterized as plastic fracture. Introduction Specific strength of aluminum alloy is high, so aluminum alloys reduce the weight of the structure compared with steel structures. Aluminum alloys have a broad application prospect in aerospace, automotive, and marine industries based on their good corrosion resistance, low temperature resistance, good processability, and rich alloy system (Kuk et al. 2004; Wang &amp; Zhang 2015; Canepa et al. 2018; Gaur et al. 2018; Qiang &amp; Wang 2019). In recent years, to reduce the weight of the structure such as trimaran hull and improve speed, aluminum alloys have been more and more applied in shipbuilding. But there are many problems in the welding of aluminum alloy.

Mild Steel GMA Welds Microstructural Analysis and Estimation Using Sensor Fusion and Neural Network Modeling.

This study aims at evaluating the efficiency of sensor fusion, based on neural networks, to estimate the microstructural characteristics of both the weld bead and base material in GMAW processes. The weld beads of AWS ER70S-6 wire were deposited on SAE 1020 steel plates varying welding voltage, welding speed, and wire-feed speed. The thermal behavior of the material during the process execution was analyzed using thermographic information gathered by an infrared camera. The microstructure was characterized by optical (confocal) microscopy, scanning electron microscopy, and X-ray Diffraction tests. Finally, models for estimating the weld bead microstructure were developed by fusing all the information through a neural network modeling approach. A R value of 0.99472 was observed for modelling all zones of microstructure in the same ANN using Bayesian Regularization with 17 and 15 neurons in the first and second hidden layers, respectively, with 4 training runs (which was the lowest R value among all tested configurations). The results obtained prove that RNAs can be used to assist the project of welded joints as they make it possible to estimate the extension of HAZ.

Bead shape control in wire based plasma arc and laser hybrid additive manufacture of Ti-6Al-4V

Wire based plasma transferred arc (PTA)-laser hybrid additive manufacture has the potential to build large-scale metal components with high deposition rate and near-net shape. In this process, a single bead is the fundamental building block of each deposited component, and thus the bead shape control is essential for the deposition of different geometries. However, how to control the bead shape by manipulating various process parameters is still not understood. In this study, the effect of different process parameters, including laser power, energy distribution between the PTA and laser, wire feed speed, travel speed, and laser beam size on the deposition process and bead shape was investigated systematically. The results show that the optimum operating regime for the hybrid process is with the wire being fully melted by the PTA and the melt pool being controlled by the laser, which gives a good bead shape as well as a stable deposition process. The bead shape is significantly affected by the laser power and travel speed due to the large variation in energy input. The effect of wire feed speed is more complex with the bead width initially increasing to a maximum and then decreasing as the wire feed speed increases. The laser beam size has a minor effect on the bead shape, but a small beam size will result in an irregular bead appearance due to the unstable process caused by the high power density. In addition, a procedure for controlling the bead shape in the hybrid process was proposed, which provided a reference for selection of different process parameters to achieve required bead shapes. The feasibility of this proposed procedure was demonstrated by the two deposited multi-layer single-pass walls. • The bead shape control in wire based plasma arc-laser hybrid additive manufacture was investigated. • The effect of different process parameters on the deposition process and bead shape was obtained. • A procedure for selecting different process parameters for achieving required bead shapes was proposed. • The feasibility of the proposed procedure was demonstrated by the deposited multi-layer single-pass walls.

Effects of process parameters on bead shape, microstructure, and mechanical properties in wire + arc additive manufacturing of Al0.1CoCrFeNi high-entropy alloy

The goal of this study is to investigate the wire + arc additive manufacturing (WAAM) of a high-entropy alloy (HEA) and to identify the near-optimal process parameters. To achieve the goal, a two-stage investigation is attempted using pre-alloyed and extruded Al 0.1 CoCrFeNi wire. In the first stage, single-layer beads are deposited with a range of process parameters (current, wire feed speed, and travel speed). Through process-signal monitoring, bead cross-section measurements, and statistical analysis, the threshold of energy density (≥80 J/mm 3 ) for the uniform and continuous bead has been identified. In the second stage, thin-walled, multi-layer structures are deposited using two heat input conditions (low and high) with the same energy density. Large columnar grains with cellular dendritic substructures and a homogeneous composition are observed in both. Almost identical yield strength (260 MPa) and ultimate tensile strength (420 MPa) are measured with exceptional ductility (45–55%) for both deposits, which can be superior to casting and other AM processes. The high heat input is identified as the near-optimal processing condition, due to the improved surface quality, the higher ductility, and the higher deposition rate.

METHOD TO DEFINE MEASUREMENT UNCERTAINTY FOR DESIGN SPACE EXPLORATION IN ADDITIVE MANUFACTURING

AbstractAdditive manufacturing is a process used for quick prototyping in industries. Geometrical defects are observed on printed parts. The aim of the paper is to propose a design method to implement measurements uncertainties into a Design Space for Additive Manufacturing parameters selection. To do so, two tests have been realized. The first test consists in determining the instrument’s uncertainty by measuring a standard length several times by an operator. The second test aim to determine the uncertainty within operators mesurement of geometric outputs (clad’s height, clad’s width, dilution’s height, dilution’s width and contact angle). Based on the results of our tests, uncertainties have been applied in our Design Space populated with 31 real printed clads. The uncertainties display with error bars on scatterplots allow to capitalize the knowledge for his/her exploration of the Design Space for future prints. The given information provides to ease the engineer to select the optimal solution (laser power, tool speed and wire feed speed) for his/her given Additive Manufacturing problematic among candidate points