Prediction of Boundary Conditions and Hot Spots during the Start-up Phase of an Extrusion Ingot Casting

  1. Dipl.-Ing. K. Ehrke Chairman3 and
  2. Prof. Dr. W. Schneider4
  1. Steinar Benum1,
  2. Dag Mortensen2 and
  3. Hallvard Fjær2

Published Online: 21 APR 2006

DOI: 10.1002/3527607331.ch8

Continuous Casting

Continuous Casting

How to Cite

Benum, S., Mortensen, D. and Fjær, H. (2000) Prediction of Boundary Conditions and Hot Spots during the Start-up Phase of an Extrusion Ingot Casting, in Continuous Casting (eds K. Ehrke and W. Schneider), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, FRG. doi: 10.1002/3527607331.ch8

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

    Hydro Aluminium R&D Materials Technology, N-6600 Sunndalsøra, Norway

  2. 2

    Institute for Energy Technology, N-2027 Kjeller, Norway

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;
  • extrusion ingot casting;
  • boundary conditions;
  • hot spots

Summary

During the start-up phase of an extrusion ingot casting hot tears or shrinkage porosity may form from the centre cone of the starting block. If this occurs for alloys susceptible to hot tearing, the hot tear may extend through the length of the casting. It was suspected that a starting block with a relatively large cone in the centre led to a hot spot at the top of the cone. Temperature measurements in the ingot and the starting block during the start up phase and transient calculations of the start-up phase of the process indicated that the temperature in the upper part of the cone was above the solidus temperature for the investigated alloy. Calculations involving the coupled evolution of the temperature-, fluid flow- and stress-field during casting (ALSIM/ALSPEN) were also performed. Here, the influence of the thermally induced deformations on the heat transfer at the ingot surfaces were included in the boundary conditions of the heat and fluid flow model. The results from modelling and the experimental measurements were compared. A clear correlation is found between the formation of hot tearing and the calculated stresses and temperature gradients. Furthermore, the simulations indicate that reducing the cone height will reduce the hot tearing probability.