Plasma diode electron beam heat treatment of cast iron

Effect of direct preheating

Eun Goo Kang, Hon Zong Choi, Byung-Kwon Min, Sang Jo Lee

Research output: Contribution to journalArticle

Abstract

Cast iron is relatively cheap and highly machinable and is thus used for various mechanical parts. However, cast iron (H2 grade) is a high-carbon steel that shows cracks or craters owing to the martensitic transformation during conventional surface heat treatments. In this study, we investigated electron-beam (e-beam)-based direct preheating for preventing the formation of craters and cracks during the heat treatment of cast iron using a plasma diode e-beam. Scanning electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and hardness measurements were performed to elucidate the crater and crack formation mechanism. Craters were formed within the graphite phase, owing to the low-melting-point elements and compounds. It was also observed that crack and crater formation was correlated to the distortion of the primary gamma phase, based on a significant decrease in the d-spacings. The direct preheating process resulted in a lower degree of distortion of the gamma phase. As a result, we could achieve a hardness as high as 800 HV without cracks or craters in cast iron, which is a cheap material. Moreover, the results of potentiodynamic polarization tests showed that the corrosion resistance increased after the surface treatment, owing to the removal of the low-melting-point impurities and grain refinement.

Original languageEnglish
Pages (from-to)1339-1345
Number of pages7
JournalInternational Journal of Precision Engineering and Manufacturing
Volume18
Issue number10
DOIs
Publication statusPublished - 2017 Oct 1

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Plasma diodes
Preheating
Cast iron
Electron beams
Heat treatment
Cracks
Melting point
Hardness
Potentiodynamic polarization
Grain refinement
Martensitic transformations
Crack initiation
X ray diffraction analysis
Carbon steel
Corrosion resistance
Surface treatment
Graphite
Impurities
Scanning electron microscopy

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

Cite this

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abstract = "Cast iron is relatively cheap and highly machinable and is thus used for various mechanical parts. However, cast iron (H2 grade) is a high-carbon steel that shows cracks or craters owing to the martensitic transformation during conventional surface heat treatments. In this study, we investigated electron-beam (e-beam)-based direct preheating for preventing the formation of craters and cracks during the heat treatment of cast iron using a plasma diode e-beam. Scanning electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and hardness measurements were performed to elucidate the crater and crack formation mechanism. Craters were formed within the graphite phase, owing to the low-melting-point elements and compounds. It was also observed that crack and crater formation was correlated to the distortion of the primary gamma phase, based on a significant decrease in the d-spacings. The direct preheating process resulted in a lower degree of distortion of the gamma phase. As a result, we could achieve a hardness as high as 800 HV without cracks or craters in cast iron, which is a cheap material. Moreover, the results of potentiodynamic polarization tests showed that the corrosion resistance increased after the surface treatment, owing to the removal of the low-melting-point impurities and grain refinement.",
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Plasma diode electron beam heat treatment of cast iron : Effect of direct preheating. / Kang, Eun Goo; Choi, Hon Zong; Min, Byung-Kwon; Lee, Sang Jo.

In: International Journal of Precision Engineering and Manufacturing, Vol. 18, No. 10, 01.10.2017, p. 1339-1345.

Research output: Contribution to journalArticle

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