Showing papers on "Welding published in 2017"
TL;DR: In this paper, the authors investigated comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. But no model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications.
Abstract: This paper investigates comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. The methods employed comprise the use of adhesive, self-piercing rivet, bolt, clinching and welding to join only CFRP and aluminium alloys. The non-thermal joining methods received great attention though the welding process has high potential in joining these materials. Except adhesive bonding and welding, other joining methods require the penetration of metallic pins through joining parts and therefore, surface preparation is unimportant. No model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications. The choice of bonding methods depends primarily on the specific applications. The load-bearing mechanism of bolted joints is predominantly the friction that is the first stage resistance. Hybrid joints performance is enhanced by combining rivets, clinch or bolts with adhesives.
357 citations
TL;DR: Friction stir welding (FSW) has achieved remarkable success in the joining and processing of aluminium alloys and other softer structural alloys, however, it has not been entirely successful in the manufacturing of different desired materials essential to meet the sophisticated green globe requirements as discussed by the authors.
347 citations
TL;DR: In this article, the authors summarize the developments in the joining of Al alloys over the recent years and provide guidance for the industry and researchers dealing with joining of these alloys.
Abstract: The mass saving potential of light-weight materials, such as Al alloys, is beneficial for fuel economy and reducing CO2 emissions. However, the wide-spread use of these alloys has been long hindered due to the difficulty in fusion joining as well as their high cost. Welding of Al alloys, which are considered to be difficult to weld through conventional arc welding, is now possible by either of low heat input arc welding, high-power density fusion joining, such as laser beam welding and electron beam welding, or friction stir welding. Particularly, friction stir welding can be successfully applied to these materials owing to the fact that no melting takes place in the weld nugget. The aim of this overview is to summarize the developments in the joining of Al alloys over the recent years. This study is also intended to provide guidance for the industry and researchers dealing with joining of these alloys.
301 citations
TL;DR: In this paper, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are reviewed and the results indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding.
227 citations
TL;DR: In this article, the effect of welding processes and conditions on microstructure, mechanical properties and corrosion resistance of duplex stainless steels and its various combinations on the basis of structure-property co-relationship are systematically highlighted.
219 citations
TL;DR: In this article, a detailed review of welding and joining processes applied to NiTi, in similar and dissimilar combinations considering both fusion and solid-state processes, is presented, and a special section is devoted to this technique.
211 citations
TL;DR: In this paper, the authors model non-isothermal polymer relaxation, entanglement recovery, and diffusion processes that occur post-extrusion to investigate the effects that typical printing conditions and amorphous (non-crystalline) polymer rheology have on the ultimate weld structure.
203 citations
TL;DR: A novel concept for welding 3D-printed thermoplastic interfaces using intense localized heating of carbon nanotubes (CNTs) by microwave irradiation is reported, which opens up entirely new design spaces for additive manufacturing and also yields new insight into the coupling between dielectric properties and radio frequency field response for nanomaterial networks.
Abstract: Additive manufacturing through material extrusion, often termed three-dimensional (3D) printing, is a burgeoning method for manufacturing thermoplastic components. However, a key obstacle facing 3D-printed plastic parts in engineering applications is the weak weld between successive filament traces, which often leads to delamination and mechanical failure. This is the chief obstacle to the use of thermoplastic additive manufacturing. We report a novel concept for welding 3D-printed thermoplastic interfaces using intense localized heating of carbon nanotubes (CNTs) by microwave irradiation. The microwave heating of the CNT-polymer composites is a function of CNT percolation, as shown through in situ infrared imaging and simulation. We apply CNT-loaded coatings to a 3D printer filament; after printing, microwave irradiation is shown to improve the weld fracture strength by 275%. These remarkable results open up entirely new design spaces for additive manufacturing and also yield new insight into the coupling between dielectric properties and radio frequency field response for nanomaterial networks.
202 citations
TL;DR: In this article, the potential for the use of lightweight materials (aluminum alloys, magnesium alloys and titanium alloys) in high volume vehicle manufacturing is discussed. And the feasibility of implementing these techniques in the industrial setup is discussed, and mechanical properties of welds such as hardness, shear and tensile strength are analyzed.
189 citations
TL;DR: Capillary force is a powerful driving force that can effectively cause self-limited cold welding of the wire-wire junction for AgNWs and can be useful in the welding of other metal NWs, the fabrication of nanostructures, and smart assemblies for versatile flexible optoelectronic applications.
Abstract: Silver nanowire (AgNW) films have been studied as the most promising flexible transparent electrodes for flexible photoelectronics. The wire–wire junction resistance in the AgNW film is a critical parameter to the electrical performance, and several techniques of nanowelding or soldering have been reported to reduce the wire–wire junction resistance. However, these methods require either specific facilities, or additional materials as the “solder”, and often have adverse effects to the AgNW film or substrate. In this study, we show that at the nanoscale, capillary force is a powerful driving force that can effectively cause self-limited cold welding of the wire–wire junction for AgNWs. The capillary-force-induced welding can be simply achieved by applying moisture on the AgNW film, without any technical support like the addition of materials or the use of specific facilities. The moisture-treated AgNW films exhibit a significant decrease in sheet resistance, but negligible changes in transparency. We have...
189 citations
TL;DR: In this article, a systematic in-depth analysis of diversified aspects of ultrasonic application in metal joining and processing including its limitations, future prospects and assessments are classified and discussed, and detailed state-of-the art, experimentation and progresses of the ultrasonic vibrations and its applications in the above areas are comprehensively examined, evaluated and presented for exhaustive understandings of its physical mechanism.
TL;DR: In this paper, a physics-based model for keyhole welding including heat transfer, fluid flow and interfacial interactions has been used to simulate keyhole and porosity formation during laser welding of Ti-6Al-4V titanium alloy.
TL;DR: A hybrid multi-objective discrete grey wolf optimizer (HMOGWO) is proposed to solve the dynamic welding scheduling problem and outperforms other algorithms in terms of convergence, spread and coverage.
TL;DR: Friction stir welding (FSW) of steels has reached a new level of technical maturity with the development of reliable welding tools and precise control systems in the past two decades as mentioned in this paper.
TL;DR: In this paper, the porosity formation takes three steps: bubble formation, bubble floating to the back of molten pool and bubble being captured by solidification front, and porosity prevention can be achieved by interrupting one of these three steps.
TL;DR: In this paper, a review article has been made to critically analyse the issues and challenges associated with the weldability of high strength pipeline materials, including welding corrosion, hydrogen embrittlement, residual stress, weld repairing and deteriorated heat affected zone.
TL;DR: In this article, solid-state friction stir welding with different tool rotation and welding speeds was used to obtain a quality joining of steels to aluminum alloys by fusion welding processes due to the large difference between melting temperatures and the formation of brittle Al/Fe intermetallic compounds at the joint interface.
TL;DR: In this paper, the microstructures and crystallographic textures of base materials (BM) and the welds were investigated using electron backscatter diffraction (EBSD) technique.
TL;DR: In this paper, the evolution of grain structure and topology in three dimensions in both the FZ and the HAZ considering the motion of the liquid pool was investigated. And the results showed that the grain size distributions and topological class distributions were largely unaffected by the temporal and spatial variations of the temperature created by different welding parameters.
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.
TL;DR: In this article, a review on the resistance spot welding (RSW) of Al/Al alloys, Al alloys/steel, Al/Mg alloys and Al/Ti alloys with focus on structure, properties, and performance relationships is presented.
Abstract: This paper presents a review on the resistance spot welding (RSW) of Al/Al alloys, Al alloys/steel, Al/Mg alloys, and Al/Ti alloys, with focus on structure, properties, and performance relationships. It also includes weld bonding, effect of welding parameters on joint quality, main metallurgical defects in Al spot welds, and electrode degradation. The high contact resistance, induced by the presence of oxide layer on the surface of Al alloys, and the need for application of high welding current during RSW of Al alloys result in rapid electrode tip wear and inconsistency in weld quality. Studies have shown that cleaning the oxide layer, sliding of a few microns between sheets, enhancing the electrode force, and the application of a low-current pre-heating can significantly reduce the contact resistance and improve joint quality. For Al/steel dissimilar RSW, the technique of resistance element welding, the use of optimized electrode morphology, the technique of RSW with cover plates, and the use of interlayers such as Al-Mg, AlSi12, and AlCu28 alloys were found to suppress the formation of brittle intermetallic compounds (IMC) and improve the joint quality. The employment of pure Ni foil, Au-coated Ni foil, Sn-coated steel, and Zn-coated steel interlayers was also found to restrict the formation of brittle IMCs during RSW of Al/Mg alloys. Furthermore, the techniques of RSW with cover plates and RSW under the influence of electromagnetic stirring effect were found to improve the weldability of Al/Ti dissimilar alloys.
TL;DR: In this article, the porosity of laser arc hybrid welded AA6082 aluminum alloy was examined by X-ray non-destructive testing and a volume characteristic coefficient was proposed by pool profiles to predict the percent porosity.
Journal Article•
TL;DR: In this paper, the authors investigated comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. But no model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications.
TL;DR: In this article, the authors measured the residual stress of lap joints of thin steel sheets by the cosα X-ray diffraction method and compared with the numerical simulation, and found that the longitudinal residual stress in the region near the weld is close to the yield strength of the base metal.
TL;DR: In this paper, residual stresses and distortions due to time dependent and localised heating imposed during fiber laser welding a 2.0mm thick titanium alloy Ti-6Al-4V sheet were studied.
TL;DR: A robust automatic welding seam identification and tracking method by utilizing structured-light vision and a character string method is proposed to qualitatively describe the welding seam profile, which might consist of different segment and junction relationship elements.
Abstract: In the automatic welding process on mid/thick plates, the precision of the welding position has an important effect on welding quality, which mainly relies on the identification of the welding seam. However, due to some possible disturbances in complex unstructured welding environments, e.g., strong arc lights, welding splashes, thermal-induced deformations, etc., it is a great challenge to identify the welding seam. In this paper, we propose a robust automatic welding seam identification and tracking method by utilizing structured-light vision. First, after the preprocessing of the welding image, the gray distribution of the laser stripe is tracked and the profile of the welding seam is searched in a small area by using the Kalman filter, with the aim to avoid some disturbances. Second, in order to extract the welding seam profile, a series of centroids obtained by scanning the columns in the rectangular window are fitted using the least-squares method. Third, a character string method is proposed to qualitatively describe the welding seam profile, which might consist of different segment and junction relationship elements. And then, these character strings acquired from the object image are matched with those from the model, so that the position of the welding seam can be determined. Finally, the advantages of the new algorithm are testified and compared through several experiments.
TL;DR: In this article, the friction stir welding process has been employed to join similar and dissimilar 2.5mm thick sheets of AA2219-O and AA 7475-T761 aluminium alloys.
TL;DR: In this article, a review of metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing is presented.
TL;DR: A finite element analysis based on the Coupled Eulerian-Lagrangian formulation was developed to predict and quantify the influence of FSW process parameters on the formation and extent of the banded structures.
TL;DR: In this paper, a portable spectrometer based on a linear CCD is designed with real-time acquisition and processing of spectral data in the welding process of aluminum alloys, which extracts several characteristic spectral lines and calculates the intensity ratio between H I and Ar I.