The cable-type welding wire (CWW) submerged arc surfacing (SAS) is an innovative welding process with the advantages of high efficiency, energy saving, and good welding quality. At present, this ...welding process has been applied to repair the large structure. This study investigate the arc heat efficiency and arc heat distribution of CWW SAS using the mathematical calculation method. The deposition rate and the surfacing layer area of CWW SAS increases with the increasing welding current. The deposition rate and the surfacing layer area of CWW SAS are larger than those in single-wire SAS. The ratio of the surfacing layer area between CWW SAS and single-wire SAS is similar to the ratio of the surfacing deposition rates between CWW SAS and single-wire SAS. The efficiency of the arc heat on melting wire in CWW SAS is larger than that in single-wire SAS. The arc heat working on base metal in CWW SAS is lower than that in single-wire SAS, leading to a smaller molten base metal area. The arc heat working on droplet transfer in CWW SAS is greater than that in single-wire SAS, leading to a larger surfacing area.
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•Al-Zn-Mg alloy suffers severer corrosion with T4 condition than with T5 condition.•The corrosion resistance of various zones after welding is different.•The heat affected zone can be ...further divided into two zones.•The difference of corrosion potential results in severe galvanic corrosion.
The 7N01-T5 alloy (AT5) and 7N01-T4 alloy (AT4) were butt welded by metal inert gas (MIG) welding with ER5356 filler wire, and the mechanical properties and corrosion resistance of welded joint were investigated. The mechanical properties of welded joint are inferior to those of base metals (BMs). In the welded joint, the difference in composition of Zn, Cu and the amount of precipitates between AT5 side and AT4 side induces the variance of corrosion potential, resulting in the appearance of galvanic corrosion, then the highest corrosion susceptibility occurred on the AT4 side of the region adjacent to the weld zone.
7N01-T4 aluminum alloy plates were welded by the metal inert gas (MIG) welding method, with ER5087 and ER5356 welding wires, respectively. The electrochemical corrosion behavior of the weld zones in ...the two kinds of welded joints using 3.5 wt.% and 5 wt.% NaCl solutions were investigated by polarization curve, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and laser confocal scanning microscope (LCSM). The results indicated the better corrosion resistance of the weld zone in the ER5356 welded joint than that in the ER5087 welded joint, which was related to the different contents of Mn and Zn elements and the distribution of precipitates for the weld zones in the two kinds of welded joints. Based on the LSCM of the weld zones, the maximum depth (
) of corrosion pits for the weld zone in the ER5356 welded joint was lower than that in the ER5087 welded joint when immersed in the same NaCl concentrations. The
of the corrosion pit of the weld zone in the ER5356 welded joint using the 5 wt.% NaCl solution was 78.5 ± 0.96 μm, which was much bigger than that using the 3.5 wt.% NaCl solution. For the weld zone in the ER5087 welded joint with 5 wt.% NaCl solution, more Cl
was adsorbed onto the active surface of weld zones, which accelerated the corrosion, resulting in the corrosion mechanism from pitting to intergranular corrosion.
In this study, we designed and developed a combined cable wire made of NbMoTaNiCr multi-principal alloys to meet the demand for high-temperature structural materials. On this basis, the gas tungsten ...arc welding (GTAW) wire arc additive manufacturing (WAAM) experiments of NbMoTaNiCr multi-principal alloys were conducted, and the microstructure and mechanical properties of the formed layer were analyzed and tested. The result showed that the formed NbMoTaNiCr multi-principal alloys layer at room temperature mainly exhibited a face-centered cubic (FCC) structure with a small amount of μ-phase. The microstructure exhibited the formation of fine and uniform dendrites, with certain dendrite segregation, accompanied by the changed elemental distribution. The high-temperature structural phases of the formed NbMoTaNiCr multi-principal alloys layer were BCC, FCC, B2, and μ-phase; the average hardness of the formed layer at room temperature was 911 HV, higher than that of all other systems with a solid-solution structure reported in the literature. At room temperature, the yield strength of the formed layer was 545.5 MPa, and the fracture strain was 9.5%. At 750 and 1100 °C, the fracture strains of the formed layer was 6.5 and 6.8%, respectively, while the corresponding yield strength of the formed layer was 597 and 490 MPa, much better than that of the conventional high-temperature alloy Inconel 718 (200 MPa) at 1000 °C.
•Wire arc additive manufactured NbMoTaNiCr RHEA with FCC structure and high hardness 911HV.•Combined cable wire with multi-element composition has been designed and developed to solve engineering preparation problem of HEA wire.•Microstructure, phase constitutes, and mechanical properties were studied.•This study provides a way to fabricate large-sized refractory high entropy alloy with high efficiency and low cost.
Wall structures were made by cold metal transfer-based wire and arc additive manufacturing using two kinds of ER2319 welding wires with and without Cd elements. T6 heat treatment was used to improve ...mechanical properties of these wall structures. Due to the higher vacancy binding energy of Cd, Cd-vacancy clusters are formed in the aging process and provide a large number of nucleation locations for θ′ phases. The higher diffusion coefficient of the Cd-vacancy cluster and the lower interfacial energy of θ′ phase lead to the formation of dense θ′ phases in the heat-treated α(Al). According to the strengthening model, after adding Cd in ER2319 welding wires, the yield strength increases by 43 MPa in the building direction of the heat-treated wall structures.
Manufacturers of welding wire electrodes for GMAW welding adapt the alloy compositions of welding wire electrodes in order to adjust the weld pool behavior and the properties of the weld. Additively ...manufactured components in various sizes and with complex structures and multi-axial stress states place diverse demands on the material. The filler wire can significantly influence the material properties. The approach shown here describes the possibility of coating welding wire electrodes by physical vapor deposition, which enables flexible adjustment of the welding material composition. The element content in the weld metal can be adjusted within certain limits via the coating thickness. In the arc, applied thin-film coatings with coating thicknesses < 1 µm pass into the molten phase together with the substrate wire electrode according to ISO 18273—S Al 5754 (AlMg3). Microalloying elements such as TiB
2
or Ti added to the weld pool in this way change the composition and thus influence the microstructure in the weld metal. This results in a grain refinement of up to 46%, which in turn has a positive effect on hot cracking susceptibility. PVD-coated welding electrodes also show changes in arc characteristics. With increasing TiB
2
layer thickness, the arc length decreases by up to 44%, while the arc current increases. The fusion penetration behavior changes from a narrow finger-shaped to a round fusion penetration.
To solve the lack of sidewalls penetration in gas metal arc welding (GMAW), a swing TIG-MIG hybrid welding method was proposed and applied in the narrow gap welding. The arc shapes and voltage ...changes in MIG, TIG-MIG hybrid welding and swing TIG-MIG hybrid welding were compared. The result reveals that the swing TIG-MIG hybrid welding can be used in narrow gap welding to attain good sidewall penetration. The assisted TIG arc can widen the MIG weld width and obtain good sidewall penetration, and stabilize the MIG welding voltage thereby improving welding quality. The melted welding wire in the MIG welding molten pool will spread to the TIG welding molten pool, which makes the weld width increased and the welding spread improved.
Abstract Using laser filler wire welding technology, welded joints were produced at varying wire feeding speeds. The microstructure and mechanical attributes of these joints were then examined ...through optical metallography, scanning electron microscopy, universal tensile testing, and microhardness testing. It demonstrates that superior surface formation and defect-free welded joints can be achieved through the filling wire welding process. The main components are austenite and ferrite, with slightly varying morphology and content. Through the results of tensile tests and fracture microstructure scanning, when the rate of wire supply is 2.0 meters per minute, the tensile strength reaches 650 MPa. The second phase particles were discovered in the fracture scan. According to microhardness measurements, the overall hardness of the welded joints at different wire feeding speeds is higher than that of the base material.
A laser penetration welding-brazing combined with Cold Metal Transfer (CMT) arc, was proposed to improve weld shape and interfacial reaction inhomogeneity of 5052 aluminum alloy and Q235 low carbon ...steel with ER5356 welding wire in butt joint. The effects of wire feed speed, beam offset and welding speed on weld shape, interfacial microstructures and tensile strength of joints was studied. This method improved the undercut defect existed in butt laser welding-brazing, obtained well-formed joints and promoted the uniform distribution of the interface reaction. The interfacial intermetallic compounds (IMCs) layer consisted of Fe2Al5 and Fe4Al13 and the thicknesses were controlled to 3-5 μm. Microstructures of weld seam was composed of α-Al and Al3Mg2. The brittle IMCs layer thickened and then the tensile strength decreased with increasing the wire feed speed. The thickness of the IMCs layer decreased but weld shape became worse when the welding speed or the offset increased. The tensile strength increased first and then decreased. The highest tensile strength reached higher than 80 MPa and the joint fractured in IMCs layer along the interface.
Cast defects could severely deteriorate the quality of magnesium alloy component. Repair welding is an efficient and economic method to improve the casting qualification. In this study, the impact of ...welding wire composition on the microstructures and mechanical properties of Mg–Gd–Y repair welds was investigated. The results illustrated that, the Zr in the Mg–6Gd–3Y–0.5Zr (VW63K) welding wire promoted the grain refinement in the fusion zone (FZ) of the repair weld, and VW63K FZ performed better thermal stability when subjected to 500 °C for 6 h, because the grain boundaries migration in VW63K FZ was hindered by Zr-contained particles, while the Mg–6Gd–3Y (VW63) FZ presented dramatic grain coarsening. Under as-welded, T4 and T6 conditions, the joint efficiency of VW63K repair weld was 127.64%, 113.14% and 107.37% respectively, while that of VW63 repair weld was 121.61%, 94.92% and 91.67%, respectively.
•The Zr-contained particles enhanced the thermal stability of VW63K FZ.•The VW63K repair welds presented better tensile properties than other reported welds of Mg alloys by different methods.•The repair welding current was lower than other reported works.
