Improvement of surface characteristics for long life of metal molds by large-area EB irradiation

Akira Okada, Yasuhiro Okamoto, Yoshiyuki Uno, Kensuke Uemura

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

This paper describes the applicability of large-area EB irradiation method to a new surface modification for metal molds. The previous papers clarified that the surface roughness on wide area uniformly decreased to less than 1 μm Rz in a few minutes by the large-area EB irradiation. Therefore, the large-area EB irradiation method has high practicability as an efficient surface finishing process for metal molds, and then the EB irradiation equipment has already been introduced into the market for practical use. In this method called EB polishing, the surface material melts and a very thin resolidified layer is formed on the surface. In this paper, the surface structure of EB polished metal mold steel SKD11 was first observed by TEM, and also component analysis was carried out by EDX. Then it was found out that the crystal grain size became small and chromium carbide is uniformly rearranged in the layer. Next, using heat conduction analysis model considering the electron penetration on the surface, the temperature distribution was calculated. The results showed that the surface temperature rapidly raised over its melting point until the end of EB irradiation, and cooled down rapidly. As the important practical surface characteristics for long life of metal mold, resistance to corrosion, water repellency, and the releasability of molded resin from metal mold surface were evaluated. The corrosion resistance and the water repellency could be improved by EB polishing, since the surface structure changes and Cr content distributed uniformly on the surface. Also, the releasability of molded resin from the surface became better.

Original languageEnglish
Pages (from-to)7040-7048
Number of pages9
JournalJournal of Materials Processing Technology
Volume214
Issue number8
DOIs
Publication statusPublished - Aug 2014

Fingerprint

Molds
Irradiation
Metals
Polishing
Surface structure
Resins
Life
Water
Steel
Chromium
Corrosion Resistance
Surface Modification
Heat conduction
Grain Size
Carbides
Melting point
Corrosion resistance
Surface treatment
Thin Layer
Corrosion

Keywords

  • Corrosion resistance
  • Large-area EB
  • Releasability of molded resin
  • Repellency
  • Surface modification

ASJC Scopus subject areas

  • Computer Science Applications
  • Modelling and Simulation
  • Ceramics and Composites
  • Metals and Alloys
  • Industrial and Manufacturing Engineering

Cite this

Improvement of surface characteristics for long life of metal molds by large-area EB irradiation. / Okada, Akira; Okamoto, Yasuhiro; Uno, Yoshiyuki; Uemura, Kensuke.

In: Journal of Materials Processing Technology, Vol. 214, No. 8, 08.2014, p. 7040-7048.

Research output: Contribution to journalArticle

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