Metal-cored Wire Research Articles

Layered synthesis of workpieces by mig-pulse surface method using austenitic metal-cored wire with nitrogen

Layered synthesis of workpieces by mig-pulse surface method using austenitic metal-cored wire with nitrogen

Structure and Properties of Welded Joints of High-Strength Steels Made by Metal-Cored Wire with Nitrogen

Structure and Properties of Welded Joints of High-Strength Steels Made by Metal-Cored Wire with Nitrogen

Surface plasmon enhanced THz spontaneous emission near metal-cored wires coated with graphene

This work deals with the theoretical study of the spontaneous emission of a point dipole source placed near a cylindrical structure composed of a central metallic core and a dielectric shell covered with graphene. We show that the spontaneous emission rate is dominated by coupling into surface plasmon (SP) modes on graphene, which present high values of the propagation constant along the cylinder symmetry axis. When the dielectric shell thickness is reduced, the plasmon dispersion is modified into a linear dependence and the modal SP propagation constant is further incremented, involving an improved field confinement. This effect is manifested as a redshift of the emission frequency spectrum for each individual cylindrical harmonic mode. We propose a simple model that provides us a link between the dispersion characteristics and maximum emission rate for each SP cylindrical mode.

Individual Effects of Alkali Element and Wire Structure on Metal Transfer Process in Argon Metal-Cored Arc Welding.

This study aimed to clarify the effect of wire structure and alkaline elements in wire composition on metal transfer behavior in metal-cored arc welding (MCAW). A comparison of metal transfer in pure argon gas was carried out using a solid wire (wire 1), a metal-cored wire without an alkaline element (wire 2), and another metal-cored wire with 0.084 mass% of sodium (wire 3). The experiments were conducted under 280 and 320 A welding currents, observed by high-speed imaging techniques equipped with laser assistance and bandpass filters. At 280 A, wire 1 showed a streaming transfer mode, while the others showed a projected one. When the current was 320 A, the metal transfer of wire 2 changed to streaming, while wire 3 remained projected. As sodium has a lower ionization energy than iron, the mixing of sodium vapor into the iron plasma increases its electrical conductivity, raising the proportion of current flowing through metal vapor plasma. As a result, the current flows to the upper region of the molten metal on the wire tip, with the resulting electromagnetic force causing droplet detachment. Consequently, the metal transfer mode in wire 3 remained projected. Furthermore, weld bead formation is the best for wire 3.

Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires

Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires

Aluminium-Assisted Alloying of Carbon Steel in Submerged Arc Welding with Al-Cr-Ni Unconstrained Metal Powders: Thermodynamic Interpretation of Gas Reactions

Unconstrained metal powders of chromium and nickel, in combination with aluminium, were used in the submerged arc welding (SAW) process to simplify weld metal alloying. Unconstrained metal powders refer to non-alloyed metal powders that are not constrained in tubular wire, such as fluxed-cored and metal-cored wire. Aluminium powder is used to control the oxygen potential at the molten flux–weld pool interface. The results presented here show that the addition of aluminium powder to the weld metal enhances Cr and Ni yields to 89% for Cr and 91% for Ni, compared to lower values reported in pre-alloyed powder application. Alloying of the carbon steel in the base plate and weld wire combination was achieved at 6.0% Cr, 6.2% Ni, and 4.5% Al, with the weld metal oxygen controlled to 162 ppm O. Thermodynamic analysis was applied to investigate the likely gas reactions in the arc cavity emanating from the chemical interaction between Cr, Ni, and Al. The effects of gas-based chemical reactions on the yield of Cr and Ni to the weld pool are discussed and incorporated into our SAW reaction flow diagram. Overall SAW process productivity gains can be accomplished by using unconstrained metal powders to alloy the weld metal because expensive and time consuming steps, such as the manufacturing of alloyed wire and alloyed powder, can now be eliminated.

Effect of multi-walled structure on microstructure and mechanical properties of 1.25Cr-1.0Mo steel fabricated by GMAW-based WAAM using metal-cored wire

Wire-arc additive manufacturing (WAAM) offers multiple benefits, such as high metal deposition, low capital cost, suitable mechanical properties, and reasonable costs. In the present work, Gas metal arc welding (GMAW) based WAAM was employed to manufacture a multi-walled component of 1.25Cr-0.5Mo at optimized parameters using metal-cored wire. The fabricated multi-walled structure was observed with seamless fusion and free from disbonding. The fabricated multi-walled component was studied through microstructure investigations, mechanical properties such as microhardness (MH), tensile test, and impact test at various positions (top side, middle side, and bottom side) of the built structure. Microstructure results have shown a tempered martensite structure in the bottom zone with coarse grains and finer microstructures in the middle and top zones. MH values throughout the component were uniform and thus indicated a similar nature to the multi-walled component. A comparison of tensile properties was carried out among the results of metal-cored wires and multi-walled structures to check the internal eminence of the obtained component. For all sides of the multi-walled structure, all the tensile properties were found to be in the range values of 1.25Cr-0.5Mo metal-cored wire. The results of all three conditions for impact toughness showed far better strength than the requirement. Fracture surface morphologies of tensile and impact test parts showed the presence of large dimples with the homogenous distribution. Thus, all the obtained results have suggested the suitability of the GMAWAM process for the fabrication of a multi-walled structure of 1.25Cr-0.5Mo metal-cored wire for various industrial applications.

Processing of a Martensitic Tool Steel by Wire-Arc Additive Manufacturing.

This work investigates the processability of hot-work tool steels by wire-arc additive manufacturing (DED-Arc) from metal-cored wires. The investigations were carried out with the hot-work tool steel X36CrMoWVTi10-3-2. It is shown that a crack-free processing from metal-cored wire is possible, resulting from a low martensite start (Ms) temperature, high amounts of retained austenite (RA) in combination with increased interpass temperatures during deposition. Overall mechanical properties are similar over the built-up height of 110 mm. High alloying leads to pronounced segregation during processing by DED-Arc, achieving a shift of the secondary hardness maximum towards higher temperatures and higher hardness in as-built + tempered condition in contrast to hardened + tempered condition, which appears to be beneficial for applications of DED-Arc processed material at elevated temperatures.

Metal Transfer Behavior of Metal-Cored Arc Welding in Pure Argon Shielding Gas

The metal transfer behavior of gas metal arc welding in a pure argon shielding gas was evaluated through experiments using a standard solid wire and a metal-cored wire. The investigation was conducted using observation techniques based on recording images by a high-speed camera equipped with laser assistance and bandpass filters in a range of welding currents. It was observed that the metal transfer mode became a streaming transfer mode when the welding current increased in the solid wire. Meanwhile, in the metal-cored wire, the droplet transfer frequency increased, and the droplet diameter decreased without changing the metal transfer mode in the globular transfer mode. We surmised that the streaming transfer in the solid wire would be caused by the spread of argon plasma at the wire tip, which decreases the effect of the electromagnetic force on droplet detachment. Conversely, due to the presence of flux inside the metal-cored wire, the argon plasma could not spread and was attached close to the iron vapor plasma at the overhead of the droplet. Hence, the electromagnetic force acting on the side of the unmelted flux was ineffective at promoting droplet detachment, preventing the transition to a streaming transfer mode. Furthermore, weld bead formation in the metal-cored wire was better than that in a conventional solid wire.

Effect of Flux Ratio on Droplet Transfer Behavior in Metal-Cored Arc Welding

The effect of flux ratio on metal transfer behavior during metal-cored arc welding was elucidated through investigation using a standard solid wire and three metal-cored wires with flux mass ratios of (2-2) 10%, 15%, and 20%. Investigation was performed using a shadowgraph technique based on images recorded with a high-speed camera equipped with back-laser illumination. We observed that the droplet transfer frequency increased with both the welding current and flux ratio, with the effect of flux ratio being more dominant at low currents. We surmise that this is because the wire sheath area decreases as the flux ratio is increased. Hence, when the welding current is the same, a reduction in the sheath area (i.e., an increase in flux content) leads to an increase in the current density in the sheath, which enlarges the electromagnetic force at the tip of the wire and aids droplet detachment. Conversely, Joule heating is higher at high welding currents than at low currents. This increased temperature shortens the flux column inside the wire, such that the current flow into the molten droplets is more uniform. Hence, the droplet transfer frequency does not increase significantly if the flux ratio is increased in the high current range.

Wire and Arc Additive Manufacturing of a CoCrFeMoNiV Complex Concentrated Alloy Using Metal-Cored Wire—Process, Properties, and Wear Resistance

The field of complex concentrated alloys offers a very large number of variations in alloy composition. The achievable range of properties varies greatly within these variants. The experimental determination of the properties is in many cases laborious. In this work, the possibility of using metal-cored wires to produce sufficient large samples for the determination of the properties using arc-based additive manufacturing or in detail wire and arc additive manufacturing (WAAM) is to be demonstrated by giving an example. In the example, a cored wire is used for the production of a CoCrFeNiMo alloy. In addition to the process parameters used for the additive manufacturing, the mechanical properties of the alloy produced in this way are presented and related to the properties of a cast sample with a similar chemical composition. The characterization of the resulting microstructure and wear resistance will complete this work. It will be shown that it is possible to create additively manufactured structures for a microstructure and a property determination by using metal-cored filler wires in arc-based additive manufacturing. In this case, the additively manufactured structure shows an FCC two-phased microstructure, a yield strength of 534 MPa, and a decent wear resistance.

Characterization of a low-alloy steel component produced with wire arc additive manufacturing process using metal-cored wire

Abstract In this study, a low-alloy steel component was manufactured using specially produced E70C-6M class of metal-cored welding wire according to AWS A5.18 standard for the WAAM process. The manufactured low-alloy steel component was first subjected to radiographic examination to detect any weld defect. Uniaxial tensile tests were conducted for the bottom, middle and upper regions. The micro-hardness tests were performed parallel to the deposition direction. The results show that microstructures varied from base metal to the face region of the WAAM component, including the bottom, middle and top sections. The bottom region showed lamellar structures; the middle and upper region presented equiaxed ferrite structure with a small amount of grain boundary pearlites and the face region displayed a mix of equiaxed and lamellar structures of ferrites. The yield and ultimate tensile strengths of the top, middle, and bottom regions exhibited similar results varying between 370 MPa and 490 MPa, respectively. In contrast, the top region showed an elongation value about 15% higher than other regions. Moreover, the yield and ultimate tensile strength for WAAM-produced component were found to be 14% and 24% lower than the multiple-pass all-weld metal of E70C-6M class of metal-cored wire.

Undermatched Welding of Ultra-High-Strength Steel S1100 with Metal-Cored Wire: Influence of Welding Positions on Mechanical Properties

Undermatched Welding of Ultra-High-Strength Steel S1100 with Metal-Cored Wire: Influence of Welding Positions on Mechanical Properties

Optimization of Bead Morphology for GMAW-Based Wire-Arc Additive Manufacturing of 2.25 Cr-1.0 Mo Steel Using Metal-Cored Wires

The fabrication of components involves the deposition of multiple beads in multiple layers for wire-arc additive manufacturing (WAAM). WAAM performed using gas metal arc welding (GMAW) allows for the manufacturing of parts through multiple-bead multi-layer deposition, which depends on the process variables. Thus, the selection of process parameters along with their required levels is mandatory to deposit multiple layers for WAAM. To obtain the desired levels of parameters, bead-on-plate trials were taken on the base plate of low alloy steel by following an experimental matrix produced through the Box–Behnken design (BBD) on GMAW-based WAAM. Wire feed speed, travel speed, and voltage were chosen as the input parameters and bead width and bead height were chosen as the output parameters. Furthermore, the robustness and adequacy of the obtained regression equations were analyzed by using analysis of variance (ANOVA). For both responses of BW and BH, values of R2 and adj. R2 were found to be near unity, which has shown the fitness of the model. Teaching–learning-based optimization (TLBO) technique was then employed for optimization. Within the selected range of process variables, the single-objective optimization result showed a maximum bead height (BH) of 7.81 mm, and a minimum bead width (BW) of 4.73 mm. To tackle the contradicting nature of responses, Pareto fronts were also generated, which provides a unique non-dominated solution. Validation trials were also conducted to reveal the ability and suitability of the TLBO algorithm. The discrepancy between the anticipated and measured values was observed to be negligible, with a deviation of less than 5% for all the validation trials. This demonstrates the success of the established model and TLBO algorithm. The optimum feasible settings for multi-layer metal deposition were determined after further tuning. A multi-layer structure free from any disbonding was successfully manufactured at the optimized variables. The authors suggest that the optimum parametric settings would be beneficial for the deposition of layer-by-layer weld beads for additive manufacturing of components.

Tailoring the alloy composition for wire arc additive manufacturing utilizing metal-cored wires in the cold metal transfer process

In the present study, the application and tailoring of the alloy composition of chromium martensitic hot-work steels using metal cored wires (MCW) for wire arc additive manufacturing (WAAM) in a modified short-circuit metal transfer process is demonstrated. The nickel content was varied and the alloys were fabricated as tubular-cored wires with various powder fillings. By recording the material transfer at high speed during processing, evidence was gathered indicating the suitability of the fabricated cored wires for WAAM. Optimized process parameters were identified by taking a Design of Experiment (DoE) approach and additive manufacturing (AM) structures were fabricated from the chromium martensitic hot-work tool steel alloys. The microstructure and mechanical properties of the parts were subsequently characterized. The phase fraction of the polygonally shaped delta ferrite could be reduced and microstructural refinement could be achieved by adding nickel to the investigated hot-work tool steel. In addition to molybdenum-enriched precipitates that covered the grain boundaries, randomly scattered non-metallic inclusions and oxides were observed. Modifying the microstructure by adding nickel also affects the mechanical properties of the product: an increase in hardness, impact toughness and yield strength as the nickel content increased in the AM structures fabricated by WAAM was observed.

In Situ Observation of Microstructural and Inclusions Evolution in High-Strength Steel Deposited Metals with Various Rare Earth Pr Contents.

The evolution of austenite, acicular ferrite, upper bainite and martensite, and the nucleation of inclusions in the microstructure of high-strength steel deposited metals, was systematically investigated using three kinds of A5.28 E120C-K4 metal-cored wires with various rare earth Pr contents. Grain structure evolution in the process of high temperature, dispersoid characteristics of inclusions and the crystallographic characteristics of the microstructure were assessed. Compared with no addition of Pr6O11, adding 1%Pr6O11 resulted in refined, spheroidized and dispersed inclusions in the deposited metal, leading to an increase in the pinning forces on the grain boundary movement, promoting the formation of an ultra-fine grain structure with an average diameter of 41 μm. The inclusions in the deposited metals were Mn-Si-Pr-Al-Ti-O after Pr addition; the average size of the inclusions in the Pr-containing deposited metals was the smallest, while the number and density of inclusions was the highest. The size of effective inclusions (nucleus of acicular ferrite formation) was mainly in the range of 0.6–1.5 μm. In addition, the content of upper bainite decreased, while the percentage of acicular ferrite increased by 24% due to the increase in the number of effective inclusions in the Pr-containing deposited metals in this study. This study shows that the addition of 1% Pr6O11 is efficient in achieving fine interlaced multiphase with an ultrafine-grained structure, resulting in an enhancement of the impact toughness of the deposited metal.

Effect of Interpass Temperature on Wire Arc Additive Manufacturing Using High-Strength Metal-Cored Wire

Wire arc additive manufacturing (WAAM) is suitable to fabricate large components because of its high deposition rate. In this study, a metal-cored low-alloy high-strength welding filler metal was used as feedstock. Single wall structures were prepared using the WAAM process with different interpass temperatures (150 °C, 350 °C, and 600 °C). No obvious microstructure change was observed when the alloy was deposited with the interpass temperatures of 150 °C and 350 °C. Electron backscattered diffraction analysis shows that that no significant texture is developed in the samples. The yield strength tends to decrease with the increase in interpass temperature; however, the influence is insignificant. The highest ultimate tensile strength is found at the interpass temperature of 350 °C. A higher interpass temperature can lead to a higher deposition rate because of the shorter waiting time for the cooling of the earlier deposited layer. It was found that the upper limit interpass temperature for WAAM of the low-alloy high-strength steel is 350 °C. When a higher interpass temperature of 600 °C was used, collapse of the deposited materials was observed.

The Influence of Ni on Bainite/Martensite Transformation and Mechanical Properties of Deposited Metals Obtained from Metal-Cored Wire

The multi-pass deposited metals were prepared by metal-cored wire with low (2.5 wt%) and high (4.0 wt%) Ni to research the effect of Ni on the bainite/martensite transformation. Results showed that deposited metals exhibited a multiphase structure comprised of bainite, martensite and residual austenite, which is not only explained from SEM/TEM, but also identified and quantified each phase from crystallographic structure through XRD and EBSD. With Ni content increasing, the fraction of martensite increases from 37% to 41%, and that of bainite decreases from 61% to 55% accordingly because 4% Ni element narrows the temperature range of the bainite transformation ~20 °C. The 7.8% residual austenite exhibited block and sheet in the deposited metal with low Ni, while the fraction of residual austenite was 3.26% as a film with high Ni, caused by different transformation mechanisms of bainite and martensite. The tensile strengths of deposited metals were 1042 ± 10 MPa (2.5% Ni) and 1040 ± 5 MPa (4% Ni), respectively. The yield strength of deposited metals with high Ni was 685 ± 18 MPa, which was higher than low Ni due to the high fraction of martensite. The impact values of deposited metals with high Ni content decreased because the volume fraction of bainite and residual austenite and area fraction of large-angle grain boundary were lower.

Coordinated Heat and Feed Printing Strategy for Wire and Arc Additive Manufacturing of Metal-Cored Wires

Coordinated Heat and Feed Printing Strategy for Wire and Arc Additive Manufacturing of Metal-Cored Wires

Experimental investigation on cladding with metal cored wire using GMAW process and parametric optimization

Cladding is widely used in manufacturing industries for the production of pressure vessel by depositing thick layer of filler material for providing corrosion resistant-surface. The use of metal cored wire in gas metal arc welding (GMAW) process is popular due to its higher deposition rate and productivity. This work investigates the effect of process parameters on the deposition of cladding layer with ER 309L metal core wire (as filler material) on a corrosion resistant material (IS 2062). The welding parameters viz., wire feed rate (WFR), voltage (V), welding speed (S) and nozzle to plate distance (NTD) are employed as process parameters while penetration (P), bead width (W), reinforcement (R), weld penetration shape factor (WPSF) and weld reinforcement form factor (WRFF) as welding responses. The predictive model developed for P, W, R, WPSF, and WRFF using the response surface methodology (RSM) approach is found adequate at 95% confidence interval. The validation results for the developed model results in a model accuracy (MA) of 92.82%, 96.34%, 91.47% 88.98% and 87.75% for model P, W, R, WPSF, and WRFF respectively and it shows higher predictability and accuracy. The process parameters are optimized simultaneously with integrated optimization approach using RSM with Jaya algorithm and obtain optimal solution in less than 20 number of iterations. The minimum fitness value obtained as 1.3008 at an optimal parameter setting of WFR = 12 m min−1, V = 26 V, S = 280 mm min−1, NTD = 10 mm. The validation result at the optimal parameter setting results in an improvement of 6.45%, 11.29%, 13.58%, 16.07%, 15.38% is noted for P, W, R, WPSF, and WRFF respectively.