Magnetic Pulse Welding by Electromagnetic Compression: Determination of the Impact Velocity

Lueg‐Althoff, J.; Lorenz, A.; Gies, S.; Weddeling, Christian; Goebel, Gunther; Tekkaya, A. Erman; Beyer, Eckhard

doi:10.4028/www.scientific.net/amr.966-967.489

Cited by 20 publications

(18 citation statements)

References 6 publications

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“…Clearly, HVIW is a multidisciplinary research area involving the dynamics of collisions at high velocities and pressures and the transient fluid-like thermo-mechanical behavior of metals at high strain rates and temperatures. [3] , c) Laser Impact Welding (LIW) [2], and Vaporizing Foil Actuator Welding (VFAW) [1] A striking feature of metals joined using HVIW is the emergence of a characteristic wavy morphology at the interface between the two welded workpieces. This distinctive signature, with its well-defined amplitude and wavelength, is observed in all the variants of HVIW provided that the velocity of the flier workpiece is sufficient [4,5] (e.g., > 250m/s); see Fig.…”

Section: Introductionmentioning

confidence: 99%

Shear instability of plastically-deforming metals in high-velocity impact welding

Nassiri

Kinsey

Chini

2016

Journal of the Mechanics and Physics of Solids

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High-speed oblique impact of two metal plates results in the development of an intense shear region at their interface leading to interfacial profile distortion and interatomic bonding. If the relative velocity is sufficient, a distinct wavy morphology with a well-defined amplitude and wavelength is observed. Emergence of this morphology below the melting point of the metal plates is usually taken as evidence of a successful weld. Among various proposed mechanisms, instability owing to large tangential velocity variations near the interface has received significant attention. With one exception, the few quantitative stability analyses of this proposed mechanism have treated an anti-symmetric/shear-layer base profile (i.e., a Kelvin-Helmholtz configuration) and employed an inviscid or Newtonian viscous fluid constitutive relation. The former stipulation implies the energy source for the instability is the presumed relative shearing motion of the two plates, while the latter is appropriate only if melting occurs locally near the interface. In this study, these restrictions, which are at odds with the conditions realized in high-velocity impact welding, are relaxed. A quantitative temporal linear stability analysis is performed to investigate whether the interfacial wave morphology could be the signature of a shear-driven high strain-rate instability of a perfectly plastic material undergoing a jet-like deformation near the interface. The resulting partial differential eigenvalue problem is solved numerically using a spectral collocation method in which customized boundary conditions near the interface are implemented to properly treat the singularity arising from the vanishing of the base flow strain-rate at the symmetry plane of the jet. The solution of the eigenvalue problem yields the wavelength and growth rate of the dominant wave-like

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Section: Introductionmentioning

confidence: 99%

Shear instability of plastically-deforming metals in high-velocity impact welding

Nassiri

Kinsey

Chini

2016

Journal of the Mechanics and Physics of Solids

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“…It consisted of a compression coil, a field shaper, and the workpieces (parent and flyer tubes). A Poynting SMU 0612 FS pulse power generator was used for the generation of the electrical current through the tool coil as was shown in more detail in Lueg-Althoff et al [ 20 ]. This current was recorded using a Rogowski coil type CWR 3000 B of Power Electronic Measurements Ltd. in combination with a LeCroy Waverunner 104 MXi digital oscilloscope.…”

Section: Methodsmentioning

confidence: 99%

“…This laser-based measurement technology was used because it is capable of measuring high velocities without being disturbed by the acting magnetic fields. A small size collimator probe was integrated into the field shaper (see Figure 1 ) as explained in Lueg-Althoff et al [ 20 ].…”

Section: Methodsmentioning

confidence: 99%

Magnetic Field Measurements during Magnetic Pulse Welding Using CMR-B-Scalar Sensors

Stankevič

Lueg‐Althoff

Hahn

et al. 2020

Sensors

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The possibility of applying CMR-B-scalar sensors made from thin manganite films exhibiting the colossal magnetoresistance effect as a fast-nondestructive method for the evaluation of the quality of the magnetic pulse welding (MPW) process is investigated in this paper. This method based on magnetic field magnitude measurements in the vicinity of the tools and joining parts was tested during the electromagnetic compression and MPW of an aluminum flyer tube with a steel parent. The testing setup used for the investigation allowed the simultaneous measurement of the flyer displacement, its velocity, and the magnitude of the magnetic field close to the flyer. The experimental results and simulations showed that, during the welding of the aluminum tube with the steel parent, the maximum magnetic field in the gap between the field shaper and the flyer is achieved much earlier than the maximum of the current pulse of the coil and that the first half-wave pulse of the magnetic field has two peaks. It was also found that the time instant of the minimum between these peaks depends on the charging energy of the capacitors and is associated with the collision of the flyer with the parent. Together with the first peak maximum and its time-position, this characteristic could be an indication of the welding quality. These results were confirmed by simultaneous measurements of the flyer displacement and velocity, as well as a numerical simulation of the magnetic field dynamics. The relationship between the peculiarities of the magnetic field pulse and the quality of the welding process is discussed. It was demonstrated that the proposed method of magnetic field measurement during magnetic pulse welding in combination with subsequent peel testing could be used as a nondestructive method for the monitoring of the quality of the welding process.

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“…These models are based on a rigidplastic compression of tubular shells, which are clamped on one or two sides. Details on these models were described earlier [6,9].…”

Section: Materials and Experimental Detailsmentioning

confidence: 99%

Effect of the wall thickness on the forming behavior and welding result during magnetic pulse welding

Bellmann

Lueg‐Althoff

Schulze

et al. 2019

Materialwissenschaft Werkst

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Magnetic pulse welding is a promising technology for the joining of dissimilar metals. Since the input of thermal energy is significantly reduced compared to conventional fusion welding technologies, critical intermetallic phases can largely be avoided. Therefore, proper collision conditions are necessary. Those require a careful adjustment of the energetic and geometric parameters at the impact welding setup. The thickness of the accelerated joining partner (flyer) determines the necessary energy input for a successful weld. However, at the same time, it has an effect on the weld formation. This study utilizes a novel optical measurement system to explain these findings and to gain insights into the forming behavior of the flyer parts. It is shown that the collision angle depends on the flyer tube thickness and, thus, directly has an effect on the welding result. Keywords: Magnetic pulse welding / dissimilar metal welding / wall thickness / welding window / collision conditions / solid state welding Das Magnetpulsschweißen ist eine vielversprechende Technologie zum Fügen von verschiedenartigen Metallen. Der thermische Energieeintrag ist im Vergleich zu konventionellen Schmelzschweißverfahren stark reduziert, wodurch kritische intermetallische Phasen vermieden werden. Um dieses Ergebnis zu erzielen, müssen geeignete Kollisionsbedingungen herrschen, was wiederum eine sorgfältige Einstellung der energetischen und geometrischen Randbedingungen innerhalb der Fügeanordnung erfordert. Beispielsweise bestimmt die Dicke des beschleunigten Fügepartners (Flyer) die notwendige Ladeenergie, gleichzeitig beeinflusst sie aber auch die Schweißnahtausbildung an sich. Um diese Beobachtungen zu erklären und Einblicke in das Umformverhalten des Flyers zu gewinnen, kommt in dieser Studie ein neuartiges optisches Messsystem zum Einsatz. Es wird gezeigt, dass der Kollisionswinkel von der Flyerwandstärke abhängt und damit einen direkten Einfluss auf das Schweißergebnis hat.

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Magnetic Pulse Welding by Electromagnetic Compression: Determination of the Impact Velocity

Cited by 20 publications

References 6 publications

Shear instability of plastically-deforming metals in high-velocity impact welding

Shear instability of plastically-deforming metals in high-velocity impact welding

Magnetic Field Measurements during Magnetic Pulse Welding Using CMR-B-Scalar Sensors

Effect of the wall thickness on the forming behavior and welding result during magnetic pulse welding

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