The Columnar to Equiaxed Transition in Horizontal Direct Chill Cast Magnesium Alloy AZ91

  1. Dipl.-Ing. K. Ehrke Chairman3 and
  2. Prof. Dr. W. Schneider4
  1. John F. Grandfield1,
  2. Cameron J. Davidson2 and
  3. John A. Taylor2

Published Online: 21 APR 2006

DOI: 10.1002/3527607331.ch36

Continuous Casting

Continuous Casting

How to Cite

Grandfield, J. F., Davidson, C. J. and Taylor, J. A. (2000) The Columnar to Equiaxed Transition in Horizontal Direct Chill Cast Magnesium Alloy AZ91, in Continuous Casting (eds K. Ehrke and W. Schneider), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527607331.ch36

Editor Information

  1. 3

    ALUMINIUM Essen GmbH, Sulterkamp 71, D-45356 Essen, Germany

  2. 4

    VAW Aluminium AG, Forschung und Entwicklung, Georg-von-Boeselager-Str. 25, D-53117 Bonn, Germany

Author Information

  1. 1

    CRC for Cast Metals Manufacturing (CAST), CSIRO Manufacturing Science & Technology, The University of Queensland, Australia

  2. 2

    CRC for Cast Metals Manufacturing (CAST), Department of Mining, Minerals and Materials Engineering, The University of Queensland, Australia

Publication History

  1. Published Online: 21 APR 2006
  2. Published Print: 29 NOV 2000

ISBN Information

Print ISBN: 9783527302833

Online ISBN: 9783527607334

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Keywords:

  • continuous casting;
  • horizontal direct chill cast magnesium alloy AZ91;
  • columnar

Summary

The horizontal direct chill (HDC) casting process has been investigated as a production route for magnesium remelt ingot. During this development program, HDC ingots of AZ91 were cast at two pilot plants. Ingots cast at one site exhibited columnar microstructures and were prone to formation of centreline cracks, whereas ingots cast at the other site had equiaxed microstructures and did not crack. In order to determine whether differences in the casting conditions or the melt preparation practices at the two sites were responsible for the change in the microstructure, available models of the columnar to equiaxed transition (CET) were applied. Ingot microstructures were examined and thermal data were obtained. CAFE (cellular automata finite element) modelling using the CalcoMOSTM program was also used to predict grain structures. Results showed that while increased casting temperatures can contribute to a slightly increased tendency toward formation of columnar grain structures, a change in the concentration of nuclei is a more likely cause.