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Influence of oxide scales on heat transfer in secondary cooling zones in the continuous casting process, part 1: heat transfer through hot‐oxidized steel surfaces cooled by spray‐water
Author(s) -
Köhler Christian,
Jeschar Rudolf,
Scholz Reinhard,
Slowik Jacek,
Borchardt Günter
Publication year - 1990
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199000352
Subject(s) - heat transfer , oxide , continuous casting , metallurgy , oxidizing agent , materials science , boiling , mass transfer , water cooling , casting , critical heat flux , leidenfrost effect , thermodynamics , heat flux , nucleate boiling , chemistry , physics , organic chemistry
For the cooling of steels in the continuous casting process it is necessary to know the heat transfer from the solidifying strand to the cooling water to enable calculation of the secondary cooling zone. Previous investigations have only determined this variable for non‐oxidizing metallic surfaces. For many steels cast in practice, however, the formation of oxide layers prevents a direct transfer of the previous results. In the present research the influence of the oxide layers on the heat transfer has been investigated for spay‐water cooling. Results have shown that heat transfer in the range of stable film boiling is determined for a constant spray‐water temperature in the same way as for non‐oxidizing metals, i.e. using the water mass flux density · s only. The changed surface qualities resulting from the oxide formation cause the Leidenfrost temperature, however, to shift considerably to higher values.