scholarly journals Thermal Effects in Dissimilar Magnetic Pulse Welding

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 348 ◽  
Author(s):  
Joerg Bellmann ◽  
Joern Lueg-Althoff ◽  
Sebastian Schulze ◽  
Marlon Hahn ◽  
Soeren Gies ◽  
...  
Keyword(s):  
Heat Input ◽  
High Speed ◽  
High Surface ◽  
Metal Vapor ◽  
Magnetic Pulse ◽  
Magnetic Pulse Welding ◽  
High Speed Impact ◽  
Long Time ◽  
Pulse Welding ◽  
Time Offset

Magnetic pulse welding (MPW) is often categorized as a cold welding technology, whereas latest studies evidence melted and rapidly cooled regions within the joining interface. These phenomena already occur at very low impact velocities, when the heat input due to plastic deformation is comparatively low and where jetting in the kind of a distinct material flow is not initiated. As another heat source, this study investigates the cloud of particles (CoP), which is ejected as a result of the high speed impact. MPW experiments with different collision conditions are carried out in vacuum to suppress the interaction with the surrounding air for an improved process monitoring. Long time exposures and flash measurements indicate a higher temperature in the joining gap for smaller collision angles. Furthermore, the CoP becomes a finely dispersed metal vapor because of the higher degree of compression and the increased temperature. These conditions are beneficial for the surface activation of both joining partners. A numerical temperature model based on the theory of liquid state bonding is developed and considers the heating due to the CoP as well as the enthalpy of fusion and crystallization, respectively. The time offset between the heat input and the contact is identified as an important factor for a successful weld formation. Low values are beneficial to ensure high surface temperatures at the time of contact, which corresponds to the experimental results at small collision angles.

Experimental investigation and optimization on field shaper structure parameters in magnetic pulse welding

2021 ◽  
pp. 095440542110148
Author(s):  
Yingzi Chen ◽  
Zhiyuan Yang ◽  
Wenxiong Peng ◽  
Huaiqing Zhang
Keyword(s):  
Magnetic Field ◽  
High Speed ◽  
Light Metal ◽  
Magnetic Pulse ◽  
Cross Sectional ◽  
Magnetic Pulse Welding ◽  
Pulse Welding ◽  
Sectional Shape ◽  
Welding System ◽  
The Magnetic Field

Magnetic pulse welding is a high-speed welding technology, which is suitable for welding light metal materials. In the magnetic pulse welding system, the field shaper can increase the service life of the coil and contribute to concentrating the magnetic field in the welding area. Therefore, optimizing the structure of the field shaper can effectively improve the efficiency of the system. This paper analyzed the influence of cross-sectional shape and inner angle of the field shaper on the ability of concentrating magnetic field via COMSOL software. The structural strength of various field shapers was also analyzed in ABAQUS. Simulation results show that the inner edge of the field shaper directly affects the deformation and welding effect of the tube. So, a new shape of field shaper was proposed and the experimental results prove that the new field shaper has better performance than the conventional field shaper.

scholarly journals Experimental and numerical analysis of incremental magnetic pulse welding of dissimilar sheet metals

2019 ◽  
Vol 6 ◽  
pp. 7
Author(s):  
Verena Psyk ◽  
Maik Linnemann ◽  
Christian Scheffler
Keyword(s):  
High Speed ◽  
Welding Process ◽  
Deep Understanding ◽  
Magnetic Pulse ◽  
Pulsed Magnetic Fields ◽  
Promising Alternative ◽  
Magnetic Pulse Welding ◽  
Pulse Welding ◽  
The Individual ◽  
Weld Seams

Magnetic pulse welding is a solid-state welding process using pulsed magnetic fields resulting from a sudden discharge of a capacitor battery through a tool coil in order to cause a high-speed collision of two metallic components, thus producing an impact-welded joint. The joint is formed at room temperature. Consequently, temperature-induced problems are avoided and this technology enables the use of material combinations, which are usually considered to be non-weldable. The extension of the typically linear weld seam can reach several hundred millimetres in length, but only a few millimetres in width. Incremental or sequential magnetic pulse welding is a promising alternative to obtain larger connected areas. Here, the inductor is moved relative to the joining partners after the weld sequence and then another welding process is initiated. Thus, the welded area is extended by arranging multiple adjacent weld seams. This article demonstrates the feasibility of incremental magnetic pulse welding. Furthermore, the influence of important process parameters on the component quality is investigated and evaluated. The suitability of different mechanical testing methods for determining the strength of the individual weld seams is discussed. The results of numerical simulation are consulted in order to obtain deep understanding of the observed effects.

Comparison between Simple Seam Welding and Adjacent Parallel Seam Welding by Magnetic Pulse Sheet-Welding Method

2018 ◽  
Vol 910 ◽  
pp. 19-24
Author(s):  
Tomokatsu Aizawa ◽  
Kazuo Matsuzawa
Keyword(s):  
High Speed ◽  
Magnetic Pulse ◽  
Seam Welding ◽  
Magnetic Pulse Welding ◽  
Seam Weld ◽  
Small Cavity ◽  
Welding Method ◽  
Pulse Welding

This paper describes the comparison between simple seam welding and adjacent parallel seam welding by a magnetic pulse welding method for Al-Al sheets. In the case of the parallel seam welding, the sheets collided at high speed in two parallel along a narrow central part of a one-turn flat coil. The central part had two parallel upper parts. The width of the central part was same as that of the simple seam welding. The increase of the parallel seam-weld zones was more than double in total in comparison with the simple seam-weld zones. Two inside parallel seam-weld zones were connected each other with a small cavity.

Parallel Seam Welding of Aluminum Sheets by Magnetic Pulse Welding Method with Collision between Metal Jets

2013 ◽  
Vol 767 ◽  
pp. 171-176 ◽  
Author(s):  
Tomokatsu Aizawa ◽  
Kazuo Matsuzawa ◽  
Keigo Okagawa ◽  
Masaki Ishibashi
Keyword(s):  
Magnetic Flux ◽  
High Speed ◽  
Eddy Currents ◽  
Capacitor Bank ◽  
Magnetic Pulse ◽  
Experimental Conditions ◽  
Seam Welding ◽  
Magnetic Pulse Welding ◽  
Aluminum Sheets ◽  
Pulse Welding

This paper provides details about the adjacent parallel seam welding of a pair of aluminum sheets by a magnetic pulse welding (MPW) method. An impulse discharge current from a capacitor bank passes through a flat one-turn coil and concentrates on two parallel along the narrow middle parts of the coil. A magnetic flux is suddenly generated around the middle parts. This flux intersects the sheets which are overlapped on the middle parts. The resulting eddy currents are induced in the sheets, applying two parallel strong electromagnetic forces to them. The sheets having a gap collide with each other at high speed in two parallel. In this time, four metal jets occur just ahead of the collision front along the middle parts. Two metal jets occurring in the inside collide with each other if the experimental conditions are suitable.

Thermal Effect during Electromagnetic Pulse Welding Process

2016 ◽  
Vol 879 ◽  
pp. 1662-1667 ◽  
Author(s):  
Thaneshan Sapanathan ◽  
Kang Yang ◽  
Dmitrii Chernikov ◽  
Rija Nirina Raoelison ◽  
Vladimir Gluschenkov ◽  
...  
Keyword(s):  
Joule Heating ◽  
Eddy Current ◽  
High Speed ◽  
Heat Dissipation ◽  
Welding Process ◽  
Plastic Work ◽  
Magnetic Pulse ◽  
High Speed Impact ◽  
Pulse Welding ◽  
And Control

Magnetic pulse welding (MPW) is a solid state joining process, successfully utilized to join dissimilar metals. This advantage attracted manufacturing industries to fabricate hybrid materials to attain materials with a combination of multiple attributes. The high speed impact during the welding process causes various interfacial phenomena, which have been reported in previous research studies. Combined high speed collision, Joule heating due to eddy current and plastic heat dissipation cause noticeable heating in the workpiece. The heating from the plastic work and collision energy could particularly be significant at the vicinity of the interface compared to other regions of the workpiece. The Joule heating due to eddy current affects the entire workpiece that is prominent before the collision. There is a sharp increase of the temperature at the onset of weld formation due to dissipation of plastic work during the collision. 3D simulations of coupled electromagnetic-mechanical-thermal were carried out to investigate the heating due to the combined Joule heating and plastic dissipation. A case study of MPW, consist of a one turn coil combined with a field shaper, is used to investigate the welding process. The simulations were performed using LS-DYNA®, which has the capability of using both finite and boundary elements to solve the thermo-mechanical problem during electromagnetic forming. The predicted temperature distributions from numerical simulations show expected phenomena of Joule heating and plastic heat dissipation while the analytical approach used to estimate the localized increase in temperature due to supersonic gaseous compression. Minimizing the heating effect by identifying the influencing factors could help to optimize and control the quality of the magnetic pulse welded parts.

scholarly journals Magnetic pulse welding on the cutting edge of industrial applications

2014 ◽  
Vol 19 (1) ◽  
pp. 69-81 ◽  
Author(s):  
R. M. Miranda ◽  
B. Tomás ◽  
T. G. Santos ◽  
N. Fernandes
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
High Speed ◽  
Industrial Applications ◽  
Magnetic Pulse ◽  
Magnetic Pulse Welding ◽  
Advantages And Disadvantages ◽  
Pulse Welding ◽  
The Impact ◽  
Very High

Magnetic Pulse Welding (MPW) applies the electromagnetic principles postulated in the XIXth century and later demonstrated. In recent years the process has been developed to meet highly demanding market needs involving dissimilar material joining, specially involving difficult-to-weld materials. It is a very high speed joining process that uses an electromagnetic force to accelerate one material against the other, resulting in a solid state weld with no external heat source and no thermal distortions. A high power source, the capacitor, a discharge switch and a coil constitute the minimum equipment necessary for this process. A high intensity current flowing through a coil near an electrically conductive material, locally produce an intense magnetic field that generates eddy currents in the flyer according to Lenz law. The induced electromotive force gives rise to a current whose magnetic field opposes the original change in magnetic flux. The effect of this secondary current moving in the primary magnetic field is the generation of a Lorentz force, which accelerates the flyer at a very high speed. If a piece of material is placed in the trajectory of the flyer, the impact will produce an atomic bond in a solid state weld. This paper discusses the fundamentals of the process in terms of phenomenology and analytical modeling and numerical simulation. Recent industrial applications are presented in terms of materials, joint configurations and real examples as well as advantages and disadvantages of the process.

Potentials of Pulse Magnetic Forming and Joining

2014 ◽  
Vol 907 ◽  
pp. 349-364 ◽  
Author(s):  
Eckart Uhlmann ◽  
Lukas Prasol ◽  
Alexander Ziefle
Keyword(s):  
Magnesium Alloys ◽  
Metal Forming ◽  
High Speed ◽  
Weld Zone ◽  
Basic Research ◽  
Magnetic Pulse ◽  
Magnetic Pulse Welding ◽  
High Speed Forming ◽  
Pulse Welding ◽  
Welding Processes

Magnetic pulse production methods such as forming, joining or separating demonstrate innovative high-speed processes. Such processes can be realized using a capacitor and an appropriate tool coil for forming and welding processes. The process strain rates, which can amount to 20,000 s-1, increase the formability of metallic materials significantly. Magnesium and aluminium alloys find a wider application in the automotive industry due to their light weight potential. Through the low density of these materials, the vehicle weight can be reduced considerably. Due to the hexagonal lattice of magnesium alloys industry-relevant deformation in metal forming processes can only be achieved in hot forming processes. The high-speed forming allows a significant increase of deformability of this alloy. The use of dissimilar metals in an assembly requires the development of innovative joining methods. Apart from being used form and force closure the magnetic pulse welding and adhesive bonding material with different partners is possible. Currently at the Institute for Machine Tools and Factory Management (IWF), TU Berlin, various research topics in the field of pulsed magnetic are investigated. The magnetic pulse sheet metal forming of magnesium alloys at room temperature is investigated in a basic research project. A defined demarcation of high-speed forming with respect to the quasi-static deformation is done by means of hardness measurements in the deformation zone. For this purpose a suitable experimental setup with different matrices is constructed. The experimental results of the pulse magnetic deformation are iteratively compared with simulation results. The aim is to develop a new material model which gives a precise prediction about the high-speed process. In the field of magnetic pulse welding, both basic research and industry-related research projects conducted at the IWF. The process requires an adapted tool coil geometry that meets the requirements of the weld geometry. Different coil geometries and weld geometries and possible applications are presented by way of example, the welding quality is quantified by means of different analytical methods. The material microstructure in the weld zone, characterized by light and scanning electron microscopy shows the typical features of a shock welded joint, as also observed in explosive welding.

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