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Characterization of melting and solidification phenomena in electromagnetic phenomena in electromagnetic punching of aluminum tubes

Wim De Waele UGent, Koen Faes and Wim Van Haver (2012) JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME. 134(1). p.1-10
abstract
Electromagnetic punching of tubular products is considered to be a promising innovative perforating process. The required punching energy decreases when using high velocities. Also, less tools are required when compared to conventional mechanical punching. However, the increase in punching speed can involve new strain and fracture mechanism which are characteristic of the dynamic loading. In high energy rate forming processes the effect of temperature versus time gradient on the material properties becomes important due to the heat accumulated from plastic deformation and friction. The deformation induced heating will promote strain localization in it, possibly degrade its formability and cause premature failure in the regions of high localized strain. The feasibility of the electromagnetic pulse forming process for punching holes in aluminum cylindrical specimens has been investigated on an experimental trial-and-error basis. Experiments were performed using a Pulsar system (model 50/25) with a maximum charging energy of 50 kJ and a discharge circuit frequency of 14 kHz. Microscopic and metallographic inspection of the punched workpieces, together with hardness measurements, was performed to critically evaluate the quality of the cuts. It was observed that damage occurred at part of the edge of the punched hole during some of the perforation experiments. It was evidenced that in most workpieces, especially those performed at higher charging energy levels, a considerably high temperature must have been reached in the regions near the punched hole. The aluminum in this region was assumed to have melted and resolidified. These assumptions were affirmed by the following observations. Microscopic-size precipitates present in the unaffected base metal microstructure, had completely dissolved in that region; shrinkage cavities and dendrite rich regions were clearly visible. Next to this region, a heat affected zone was present where the grain boundaries had partially melted and precipitates partially disappeared. Considerably high temperatures, in the order of 520 to 660 °C, were reached in the regions around the punched holes, leading to melting and resolidification of the material. The total width of the thermally affected regions appeared to be larger at higher energy levels. The combination of heat generated by ohmic heating and by plastic deformation in a very short time interval is the most probable cause of the high peak temperatures that have occurred during the electromagnetic punching process.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
SHEET-METAL, BLANKING, ADIABATIC SHEAR LOCALIZATION
journal title
JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME
J. Manuf. Sci. Eng.-Trans. ASME
volume
134
issue
1
article_number
011010
pages
1 - 10
Web of Science type
Article
Web of Science id
000299388100011
JCR category
ENGINEERING, MECHANICAL
JCR impact factor
0.786 (2012)
JCR rank
62/125 (2012)
JCR quartile
2 (2012)
ISSN
1087-1357
DOI
10.1115/1.4005307
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
2963646
handle
http://hdl.handle.net/1854/LU-2963646
date created
2012-07-20 10:58:01
date last changed
2012-11-12 13:31:45
@article{2963646,
  abstract     = {Electromagnetic punching of tubular products is considered to be a promising innovative perforating process. The required punching energy decreases when using high velocities. Also, less tools are required when compared to conventional mechanical punching. However, the increase in punching speed can involve new strain and fracture mechanism which are characteristic of the dynamic loading. In high energy rate forming processes the effect of temperature versus time gradient on the material properties becomes important due to the heat accumulated from plastic deformation and friction. The deformation induced heating will promote strain localization in it, possibly degrade its formability and cause premature failure in the regions of high localized strain. The feasibility of the electromagnetic pulse forming process for punching holes in aluminum cylindrical specimens has been investigated on an experimental trial-and-error basis. Experiments were performed using a Pulsar system (model 50/25) with a maximum charging energy of 50 kJ and a discharge circuit frequency of 14 kHz. Microscopic and metallographic inspection of the punched workpieces, together with hardness measurements, was performed to critically evaluate the quality of the cuts. It was observed that damage occurred at part of the edge of the punched hole during some of the perforation experiments. It was evidenced that in most workpieces, especially those performed at higher charging energy levels, a considerably high temperature must have been reached in the regions near the punched hole. The aluminum in this region was assumed to have melted and resolidified. These assumptions were affirmed by the following observations. Microscopic-size precipitates present in the unaffected base metal microstructure, had completely dissolved in that region; shrinkage cavities and dendrite rich regions were clearly visible. Next to this region, a heat affected zone was present where the grain boundaries had partially melted and precipitates partially disappeared. Considerably high temperatures, in the order of 520 to 660 {\textdegree}C, were reached in the regions around the punched holes, leading to melting and resolidification of the material. The total width of the thermally affected regions appeared to be larger at higher energy levels. The combination of heat generated by ohmic heating and by plastic deformation in a very short time interval is the most probable cause of the high peak temperatures that have occurred during the electromagnetic punching process.},
  articleno    = {011010},
  author       = {De Waele, Wim and Faes, Koen and Van Haver, Wim},
  issn         = {1087-1357},
  journal      = {JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME},
  keyword      = {SHEET-METAL,BLANKING,ADIABATIC SHEAR LOCALIZATION},
  language     = {eng},
  number       = {1},
  pages        = {011010:1--011010:10},
  title        = {Characterization of melting and solidification phenomena in electromagnetic phenomena in electromagnetic punching of aluminum tubes},
  url          = {http://dx.doi.org/10.1115/1.4005307},
  volume       = {134},
  year         = {2012},
}

Chicago
De Waele, Wim, Koen Faes, and Wim Van Haver. 2012. “Characterization of Melting and Solidification Phenomena in Electromagnetic Phenomena in Electromagnetic Punching of Aluminum Tubes.” Journal of Manufacturing Science and Engineering-transactions of the Asme 134 (1): 1–10.
APA
De Waele, W., Faes, K., & Van Haver, W. (2012). Characterization of melting and solidification phenomena in electromagnetic phenomena in electromagnetic punching of aluminum tubes. JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME, 134(1), 1–10.
Vancouver
1.
De Waele W, Faes K, Van Haver W. Characterization of melting and solidification phenomena in electromagnetic phenomena in electromagnetic punching of aluminum tubes. JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME. 2012;134(1):1–10.
MLA
De Waele, Wim, Koen Faes, and Wim Van Haver. “Characterization of Melting and Solidification Phenomena in Electromagnetic Phenomena in Electromagnetic Punching of Aluminum Tubes.” JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME 134.1 (2012): 1–10. Print.