scholarly journals Application and schemes of induction preliminary heating in magnetic-pulse treatment of metals

Author(s):  
Tetiana Gavrylova ◽  
Evgen Chaplygin ◽  
Svitlana Shynderuk

The features of the processes of magnetic-pulse processing of metals in traditional schemes of technological processes of modern industrial production are highlighted. The work is a brief description of the state, application, and also proposed induction pre-heating schemes in industrial magnetic-pulse processing of metals. A method for increasing the efficiency of performing specified production operations is considered. The use of preheating leads to a significant improvement in the quality of production operations while reducing energy consumption. New directions of magnetic-pulse processing of metals are noted, implying the transformation of the natural repulsive forces of the metal of the processed object into the forces of magnetic-pulse attraction with a decrease in the operating frequencies of the acting fields. A significant decrease in operating frequencies makes it possible not only to go from repulsion to attraction, but also to go from working with ferromagnetic metals to non-ferromagnetic ones. For example, it becomes possible to attract aluminum blanks. Examples of the use of induction heating of metal blanks in modern industry are given. Various devices used for these operations, offered on the modern market, by both domestic and foreign manufacturers, are considered. The physics of Lenz-Joule heat release is described, the result of which is the induction heating of conductors by Foucault currents in the external electromagnetic field of the instrument. Schemes are proposed for the practical implementation of preliminary induction heating during magnetic-pulse processing of metal blanks, allowing the use of both autonomous devices for exciting eddy currents and a stationary connection, for the same purpose, of an additional source of electricity. As a result of the work, the possibility of increasing the efficiency by increasing the plasticity of the metal when heating the workpiece, as well as possible limitations of the described technology associated with an increase in the active resistance of metals with an increase in the Lenz-Joule heat release is noted.

Author(s):  
Francois Bay ◽  
Jose Alves

Purpose The purpose of this paper is to study the influence of the induction heating phenomenon during magnetic pulse forming (MPF) of thin walled tube components. The approach is based on the advanced use of the multiphysics finite element software FORGE® coupling electromagnetism, heat transfer and solid mechanics. Although the global contribution of thermal effects is found to be almost negligible with respect to the volume forces, it can be observed that localized softening due to the heating process induces shock absorbing behavior. Design/methodology/approach Due to the strong multiphysics couplings between solid mechanics, electromagnetism and heat transfer, it is not always obvious to quantify the contributions of the various physical phenomena. It is thus intended here to take advantage of the numerical framework and tool that has developed to dissociate and quantify the influence of Joule heating phenomena due to eddy currents during MPF processes. Findings In this paper, the sensitivity of the MPF process has been analyzed to the induction heating source term for a specific tube forming case. An analysis of the electric output signal shows that inductance sensitivity to heating remains small when compared to the mechanical deformation. Regarding mechanical analysis of the process, induction heating contribution has a very slight impact at the global scale, but its effect is more noticeable at the small scale where it is likely that the localized heating induces shock absorption properties through softening. The extension of these results to other materials (for which the thermal dependency of mechanical behavior is different), as well as to a larger range of energy inputs, still needs to be carried out. Such phenomena should be considered for instance for high precision forming. Originality/value The analysis of the influence of heating due to eddy currents in magnetic pulse forming processes has not been extensively studied. The originality of this work is to try to quantify its effect on the process by using a numerical-based approach.


1989 ◽  
Vol 111 (2) ◽  
pp. 209-214 ◽  
Author(s):  
J. A. Tichy ◽  
K. A. Connor

The properties of magnetic bearings, particularly those based on repulsive forces due to eddy currents, are determined by a complex mixture of electrical and mechanical length and time scales. A perturbation solution for the magnetic field structure based on careful ordering of these parameters has permitted the effects of realistic gap geometries to be analyzed. The load capacity of eddy current journal bearings is found to be somewhat larger than previously predicted in an earlier paper which used magnetic fields based on constant gap size. The present results may be of interest to those concerned with calculating eddy currents in conventional attractive magnetic bearings.


2020 ◽  
Vol 2020 (5) ◽  
pp. 74-79
Author(s):  
A.P. Raschepkin ◽  
◽  
I.P. Kondratenko ◽  
O.N. Karlov ◽  
R.S. Kryshchuk ◽  
...  

2017 ◽  
Vol 43 (1) ◽  
pp. 92-94 ◽  
Author(s):  
Yu. B. Kudasov ◽  
D. A. Maslov ◽  
O. M. Surdin

2018 ◽  
Vol 64 (No. 4) ◽  
pp. 181-186 ◽  
Author(s):  
Andrey Izmailov ◽  
Igor Smirnov ◽  
Dmitriy Khort ◽  
Rostislav Filippov ◽  
Alexey Kutyrev

The effect of a pulsed low-frequency magnetic field on the seed germination and the growth of seedlings of strawberry garden under different conditions of processing and functioning of the apparatus magnetic-pulse processing of plants (MPP) developed by us has been established experimentally. The research has shown that the value of the germination energy of seeds treated with a pulsed magnetic field varied from 29 to 47 percent, of germination from 34 to 48 percent. The highest value of their germination corresponds to an irradiation frequency of 16 Hz and an exposure time of 360 seconds with an induction value in the treatment zone of 5 mT. The maximum increment in the germination of irradiated seeds was 14 percent compared to the control sample. The positive effect of pulsed electromagnetic fields on linear dimensions of germs has been revealed. The increase in the biometric parameters of strawberry shoots affected their weight, compared to the control it increased by 33.3 percent.


Author(s):  
Jinlong Zhang ◽  
Pengfei Li

SNPTRD was planning to employ cold crucible induction heating technique to investigate the corium pool heat transfer, using the UO2 and ZrO2 mixture as the simulated corium pool. Compared with the actual situation, the primary problem of the cold crucible induction heating was the additional introduction of electromagnetic field. To investigate the cold crucible applicability in simulating the corium pool heat transfer, the distribution of joule heat inside cold crucible and the magnitude of electromagnetic force were carried out. To be more suitable for heat transfer test research, the shape of cold crucible was changed to hemisphere, and the cooling water channels were set horizontally. The simulation results indicated that joule heat distribution would be more uniform with lower frequency power but considering power efficiency, there was only one best frequency. The magnitude of electromagnetic force can be ignored compared to the gravity on the natural convection research.


Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 334 ◽  
Author(s):  
Xinxin Fu ◽  
Qian Chen ◽  
Xinyu Chen ◽  
Liang Zhang ◽  
Aibin Yang ◽  
...  

Thermal nanoimprint lithography is playing a vital role in fabricating micro/nanostructures on polymer materials by the advantages of low cost, high throughput, and high resolution. However, a typical thermal nanoimprint process usually takes tens of minutes due to the relatively low heating and cooling rate in the thermal imprint cycle. In this study, we developed an induction heating apparatus for the thermal imprint with a mold made of ferromagnetic material, nickel. By applying an external high-frequency alternating magnetic field, heat was generated by the eddy currents and magnetic hysteresis losses of the ferromagnetic nickel mold at high speed. Once the external alternating magnetic field was cut off, the system would cool down fast owe to the small thermal capacity of the nickel mold; thus, providing a high heating and cooling rate for the thermal nanoimprint process. In this paper, nanostructures were successfully replicated onto polymer sheets with the scale of 4-inch diameter within 5 min.


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