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Showing papers on "Filler metal published in 2017"


Journal ArticleDOI
TL;DR: In this article, the current understanding and development of friction-stir welding and processing of Ti-6Al-4V alloy are briefly reviewed, focusing on microstructural aspects and microstructure-properties relationship.

124 citations


Journal ArticleDOI
TL;DR: In this paper, an impeller blade-like geometry out of duplex stainless steel has been manufactured by CMT using a filler wire type G 22 9 3 N L. The measured mechanical properties, especially strength and toughness, are comparable to data provided by the filler metal data sheet.
Abstract: Impeller blades are often individual and complex-shaped components made of challenging metals. As the manufacturing of such blades is highly sophisticated, only a few companies worldwide possess the necessary processing knowledge and that is why long production times have to be accepted by customers. To overcome this economic disadvantage, manufacturing technologies are permanent under supervision and it seems that metal additive manufacturing could thereby play an important role in future. In this paper, wire arc additive manufacturing (WAAM) based on gas metal arc welding (GMAW) is considered. Shape-giving GMAW is well known in industrial manufacturing, but its application is limited due to restrictions by the welding process itself: For thinner wall thicknesses, a significant reduction of the weld process energy is required which increases the risk of process instabilities and spatter formation. Extensive welding process-related efforts have been undertaken to overcome this fact and a new GMAW process, called CMT (Cold Metal Transfer) was introduced. CMT is based on a high-frequency forward and backward movement of the welding wire electrode and provides an almost spatter-free and absolute precise, periodic detachment of accurately defined droplets from the filler wire at very low process energies. In combination with an accurate robotic movement of the CMT welding torch, geometries with minimum thicknesses in the range of 2–4 mm can be build up layer by layer. Additionally, a broad range of different, well established and third party-approved GMAW filler metals for joining is available. In this work, an impeller blade-like geometry out of duplex stainless steel has been manufactured by CMT using a filler wire type G 22 9 3 N L. The investigations have shown that the achieved surface roughness is comparable to sand casting and the microstructure is without any evidence for porosity and lack of fusion. Furthermore, an austenite/δ-ferrite weld microstructure with partly preferred grain orientations and a δ-ferrite content of around 30FN exists. The measured mechanical properties, especially strength and toughness, are comparable to data provided by the filler metal data sheet.

83 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the specific microstructural features and mechanical properties, in particular tensile strength, of such welds, focusing on the material flow and welding defects, on the intermetallic compounds, on constitutional liquation, on particularities related to dissimilar lap welding and finally on process modifications to improve dissimilar friction stir weldability.
Abstract: Friction stir welding is a rather recent welding process (patented in 1991 by Thomas et al., ‘Improvements to friction welding’ UK patent application no. 9125978.8, US Patent 5460317, 1995) that has shown great potential for welding dissimilar materials even of different metallic nature, e.g. Al to steel, Mg to steel, Al to Ti, Mg to Ti, Al to Cu, Al to Mg. This review presents the specific microstructural features and mechanical properties, in particular tensile strength, of such welds. A focus will be on the material flow and welding defects, on the intermetallic compounds, on constitutional liquation, on particularities related to dissimilar lap welding and finally on process modifications to improve dissimilar friction stir weldability.

81 citations


Journal ArticleDOI
TL;DR: In this article, the effect of underwater wet welding parameters and conditions on the diffusible hydrogen content in deposited metal for welding with a self-shielded flux cored wire was reported.

75 citations


Journal ArticleDOI
TL;DR: In this paper, an external axial magnetic field (EMF) hybrid CMT welding-brazing process was adopted to join pure titanium TA2 and aluminum alloy 6061-T6.

73 citations


Journal ArticleDOI
TL;DR: In this article, a DCEN A-TIG welding was used to eliminate the welding porosity of 2219 aluminum alloy, which can reach the same mechanical performance index as VPTIG welding.

72 citations


Journal ArticleDOI
TL;DR: In this article, a laser assisted joining of AA5754 aluminum alloy to T40 titanium with use of Al-Si filler wires was carried out, where continuous Yb:YAG laser beam was shaped into double spot tandem and defocalized to cover larger interaction zone in V shaped groove.

59 citations


Journal ArticleDOI
TL;DR: In this article, the authors defined the types of external magnetic field and reviewed the development of magnetically controlled arc welding process, particularly, the effect of external Magnetic Field parameters on the welding process.
Abstract: External magnetic field (EMF) has a strong effect on the welding arc shape, droplet transfer, weld forming, microstructure, and properties of joint metal. This paper defines the types of external magnetic field and reviews the development of magnetically controlled arc welding process, particularly, the effect of external magnetic field parameters on the welding process. It is found that the welding productivity, the weld formation, the ductility, and toughness of welded metal can be improved; and the welding residual stresses, the chemical inhomogeneity, and the welding defects can be reduced. Finally, the development trend is discussed in the later sections of the paper.

58 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of laser offset (defined Al side (−) and brass side (+)) on microstructure and mechanical properties of welded-brazed joints were investigated.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of various types methods such as ATIG (Activated Fluid TIG), FBTIG (Flux Bounded TIG) and PCTIG (Pulsed Current Tungsten Inert Gas) welding was discussed.

52 citations


Journal ArticleDOI
TL;DR: In this article, Tungsten inert gas (TIG) welding method was employed to fuse Ti, Fe and Fe-Fe butt-welded joints through vanadium filler metal.

Journal ArticleDOI
Joseph Ahn1, Li Chen, Enguang He, Catrin M. Davies1, John P. Dear1 
TL;DR: In this paper, the influence of filler wire feed rate on the weld quality and mechanical properties of high power 5kW laser welded aluminium alloy 2024-T3 was investigated using energy dispersive X-ray spectroscopy.

Journal ArticleDOI
Ying Liang1, Shengsun Hu1, Junqi Shen1, Heng Zhang1, Peng Wang1 
TL;DR: In this paper, a tungsten inert gas (TIG)-cold metal transfer (CMT) hybrid welding process is proposed, which is suitable for multi-passes welding of aluminum alloy.

Journal ArticleDOI
TL;DR: In this article, the effect of the filler metal type, welding process and the welding pass number on the corrosion behavior of Incoloy 825 Ni-based alloy to SAF 2507 super duplex stainless steel weld zones were addressed utilizing scanning electron microscopy, cyclic potentiodynamic polarization and electrochemical impedance spectroscopy.

Journal ArticleDOI
Haibin Miao1, Gang Yu1, Xiuli He1, Shaoxia Li1, Xuyang Chen1 
TL;DR: In this paper, the effect of leading configuration on porosity formation and distribution in laser-MIG bead-on-plate welding of A7N01 alloy was investigated, and the results showed that leading configuration was considerable in porosity minimization and prevention.
Abstract: Laser–metal inert gas (MIG) welding is a promising welding technology, which presents many attractive properties. However, porosity still remains a serious problem in laser–MIG welding of aluminum. In this experimental study, the effect of leading configuration on porosity formation and distribution in laser–MIG bead-on-plate welding of A7N01 alloy was investigated. Experiments on arc current, welding speed, and arc configuration were performed comparatively for two leading configurations, respectively. The welds were analyzed with X-ray photographs and cross-section observations. Pores in laser–MIG-welded samples were mainly keyhole-induced. The concept of porosity area fraction was used to evaluate the severity of pore defect. The maximum porosity area fraction presented at different arc currents in the two leading configurations (in laser leading welding, it is 150 A, while in arc leading welding, it is 110 A). With welding speed increasing, porosity area fraction decreased. Bubble escape condition was deduced and used to discuss the probable mechanism of the effect of leading configuration on pore formation. The results showed that leading configuration was considerable in porosity minimization and prevention.

Journal ArticleDOI
TL;DR: In this article, a comparative study on Incoloy 825 Ni-based alloy and SAF 2507 super duplex stainless steel dissimilar joints was conducted by optical microscopy, scanning electron microscopy equipped with an energy dispersive spectroscopy and X-ray diffraction.

Journal ArticleDOI
TL;DR: In this paper, a modified flux mixture was developed to improve the butt joint performance, and the weld appearance became better and the spreadability of filler metal was also greatly improved during brazing-fusion welding process.

Journal ArticleDOI
Chen Hua1, Hao Lu1, Chun Yu1, Junmei Chen1, Xiao Wei1, Jijin Xu1 
TL;DR: In this paper, an improvement in DDC susceptibility can be attained for nickel filler metal 52M (FM-52M) through the superimposition of ultrasonic field during gas tungsten arc welding (GTAW), and a concept of Detrimental Grain Boundary Length (DGBL) has been proposed to elucidate DDC features in two kinds of samples: without ultrasound and with 20 kHz ultrasonic-assisted GTAW.

Journal ArticleDOI
Jian Cao1, Xiangyu Dai1, Jiaqi Liu1, Xiaoqing Si1, Jicai Feng1 
TL;DR: In this paper, the microstructure evolution mechanism of the joints was put forward based on the experimental analysis, and the hardness and elastic modulus of the phases in the joint were measured by nano-indentation to show the plastic deformation capacity.

Journal ArticleDOI
TL;DR: In this article, the effects of welding current (heat input) on the microstructure and mechanical behavior of the joints, which consist of Al-Al welding zone and Al-Cu brazing zone, are investigated.
Abstract: 5052 aluminum alloy and pure copper (T2) are joined, using a low heat input pulsed double-electrode gas metal arc welding (DE-GMAW)-brazing method with AlSi 12 filler metal. The effects of welding current (heat input) on the microstructure and mechanical behavior of the joints, which consist of Al-Al welding zone and Al-Cu brazing zone, are investigated. The Al-Cu welding zone mainly consists of α-Al solid solution and Al-Cu eutectic phase in coral-like shape. There exists a layer of Al 2 Cu intermetallic compound (IMC) in the Al-Cu brazing zone. Using the theory of thermal activation process, a quadratic relation between the thickness of the IMC layer and welding current intensity is derived. The experimental result supports this relationship. The shear strength of the Al-Cu joints first increases with the increase of the welding current (heat input), reaches a maximum of 17.66 MPa, and then decreases with the increase of the welding current due to the dispersion of the Al 2 Cu IMCs of large sizes in the Al alloy. Fracture of the Al-Cu lap joints occurs at three different positions, and the corresponding failure mechanisms are discussed according to the morphologies of fracture surfaces.

Journal ArticleDOI
TL;DR: In this article, the microstructural properties of the weld joints were studied with optical and Scanning Electron Microscope (SEM), and the joints fabricated by pulsed current (PC) technique showed refined microstructure, narrower weld bead and practically no heat affected zone (HAZ).
Abstract: Alloy 686 is a highly corrosion resistant 21st-Century Nickel based superalloy derived from Ni-Cr-Mo ternary system. The alloying elements chromium (Cr) and molybdenum (Mo) are added to improve the resistance to corrosion in the broad range of service environment. The presence of a higher percentage of alloying elements Cr and Mo lead to microsegregation and end up with hot cracking in the fusion zone of Nickel-based superalloys. However, there is scanty of information regarding the welding of alloy 686 with respect to the microsegregation of alloying elements. The present study investigates the possibility of bringing down the microsegregation to cut down the formation of secondary phases in the fusion zone. The weld joints were fabricated by Gas Tungsten Arc Welding (GTAW) and Pulsed current gas tungsten arc welding (PCGTAW) with ERNiCrMo-10 filler and without filler wire (autogenous) mode. The microstructural properties of the weld joints were studied with optical and Scanning Electron Microscope (SEM). The joints fabricated by pulsed current (PC) technique shows refined microstructure, narrower weld bead and practically no heat affected zone (HAZ). Scanning Electron Microscope demonstrates the presence of secondary phases in the interdendritic regions of GTAW case. Energy Dispersive X-ray Spectroscopy (EDS) analysis was carried out to evaluate the microsegregation of alloying element. The results show that the segregation of Mo noticed in the interdendritic zone of GTAW both autogenous and filler wire. Tensile and Impact tests were done to evaluate the strength, ductility, and toughness of the weld joints. The results show that the PCGTA helps to obtain improved strength, ductility and toughness of the weld joints compared to their respective GTAW. Bend test did not lead to cracking irrespective of the type of welding adopted in the present study.

Journal ArticleDOI
TL;DR: In this article, an innovative welding method referred to as adjacent welding was addressed, which greatly improved the tensile strength of a Ti/Cu dissimilar joint, and the strength of new joint could reach up to 89% that of copper base metal.

Journal ArticleDOI
Ji Chen1, Ran Zong1, Chuansong Wu1, G.K. Padhy1, Qingxian Hu2 
TL;DR: In this paper, the influence of low current auxiliary TIG arc on weld formation and microstructure in TIG-MIG hybrid welding and compared with conventional MIG welding was investigated.

Journal ArticleDOI
TL;DR: In this article, the wetting and spreading behavior of commercial pure Cu and Ag-28Cu alloy on WC-8Co cemented carbide were investigated by the sessile drop technique.
Abstract: The wetting and spreading behavior of commercial pure Cu and Ag-28Cu alloy on WC-8Co cemented carbide were investigated by the sessile drop technique. The contact angle of both systems obviously decreases with moderately increasing the wetting temperature. Vacuum brazing of the WC-8Co cemented carbide to SAE1045 steel using the pure Cu or Ag-28Cu as filler metal was further carried out based on the wetting results. The interfacial interactions and joint mechanical behavior involving microhardness, shear strength and fracture were analyzed and discussed. An obvious Fe-Cu-Co transition layer is detected at the WC-8Co/Cu interface, while no obvious reaction layer is observed at the whole WC-8Co/Ag-28Cu/SAE1045 brazing seam. The microhardness values of the two interlayers and the steel substrate near the two interlayers increase more or less, while those of WC-8Co cemented carbide substrates adjacent to the two interlayers decrease. The WC-8Co/SAE1045 joints using pure Cu and Ag-28Cu alloy as filler metals obtain average shear strength values of about 172 and 136 MPa, and both of the joint fractures occur in the interlayers.

Journal ArticleDOI
TL;DR: In this article, the effect of BN content, brazing temperature and time on the microstructure and mechanical properties of the brazed joints was investigated, and the results showed that a continuous reaction layer formed adjacent to the SiO 2 -BN ceramic and Ti plate, whose thickness played a key role in the bonding properties.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the mechanical and metallurgical properties of the joint between AZ31B and A7075-T651 alloys welded by a new technique called gas metal arc plug welding method.
Abstract: Innovative welding techniques allow for the fabrication of light, high-specific-strength, and fuel-saving Al and Mg alloys for use in transportation industries. Furthermore, these techniques have minimal detrimental impact on the environment. However, the poor mechanical properties of joints resulting from the formation of brittle Al m Mg n intermetallic compounds are key barriers to joining Al and Mg alloys. To date, a proper solution to this problem has not yet been provided. The aim of this research was to investigate the mechanical and metallurgical properties of the joint between AZ31B and A7075-T651 alloys welded by a new technique called gas metal arc plug welding method. ER5356 aluminum wire was used as a filler. The yield and ultimate tensile strengths as well as impact toughness of the joints were measured. The fracture surface was investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The maximum ultimate tensile strength and impact toughness of the joints were 89 and 84 % of those of the AZ31B parent alloy, respectively. Generally, the joints failed in the ER5356 nugget, whereas some failed in the AZ31B alloy. No fracture was observed in the A7075-T65 alloy. Brittle fracture mechanism was observed for all the joints. In conclusion, the proposed welding technique can allow for better mechanical properties of joints for dissimilar welding of aluminum and magnesium alloys.

Journal ArticleDOI
TL;DR: In this article, the microstructure and compositional changes in the joint zone were characterized using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy.

Journal ArticleDOI
TL;DR: In this article, three novel CuNi-Al brazing filler alloys with 4:1 and 2.5-10% Al were developed and characterized, and the wetting of three CuNi−Al alloys on WC-8Co cemented carbide were investigated at 1190-1210°C by the sessile drop technique.

Journal ArticleDOI
TL;DR: In this paper, a preheating method was proposed to concentrate welding energy to the joining interface to improve welding area and reduce the generation of welded edges in ultrasonic composite welding, where the maximum shear load, fracture surface and microstructure of the joint cross-sections were analyzed.

Journal ArticleDOI
25 Jul 2017
TL;DR: In this paper, the weld microstructure and those compounds over two different technologies: the laser offset welding and the hybrid laser-MIG (Metal inert gas) welding were explored.
Abstract: Welding between Fe and Al alloys is difficult because of a significant difference in thermal properties and poor mutual solid-state solubility. This affects the weld microstructure and causes the formation of brittle intermetallic compounds (IMCs). The present study aims to explore the weld microstructure and those compounds over two different technologies: the laser offset welding and the hybrid laser-MIG (Metal inert gas) welding. The former consists of focusing the laser beam on the top surface of one of the two plates at a certain distance (offset) from the interfaces. Such a method minimizes the interaction between elevated temperature liquid phases. The latter combines the laser with a MIG/MAG arc, which helps in bridging the gap and stabilizing the weld pool. AISI 316 stainless steel and AA5754 aluminum alloy were welded together in butt configuration. The microstructure was characterized and the microhardness was measured. The energy dispersive spectroscopy/X-ray Diffraction (EDS/XRD) analysis revealed the composition of the intermetallic compounds. Laser offset welding significantly reduced the content of cracks and promoted a narrower intermetallic layer.