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Abstract

Some metallographic studies performed on the basis of the massive forging steel static ingot, on its cross-section, allowed to reveal the

following morphological zones: a/ columnar grains (treated as the austenite single crystals), b/ columnar into equiaxed grains

transformation, c/ equiaxed grains at the ingot axis. These zones are reproduced theoretically by the numerical simulation. The simulation

was based on the calculation of both temperature field in the solidifying large steel ingot and thermal gradient field obtained for the same

boundary conditions. The detailed analysis of the velocity of the liquidus isotherm movement shows that the zone of columnar grains

begins to disappear at the first point of inflection and the equiaxed grains are formed exclusively at the second point of inflection of the

analyzed curve. In the case of the continuously cast brass ingots three different morphologies are revealed: a/ columnar structure, b/

columnar and equiaxed structure with the CET, and c/ columnar structure with the single crystal formation at the ingot axis. Some

forecasts of the temperature field are proposed for these three revealed morphologies. An analysis / forecast of the behavior of the

operating point in the mold is delivered for the continuously cast ingot. A characteristic delay between some points of breakage of the

temperature profile recorded at the operating point and analogous phenomena in the solidifying alloy is postulated.

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Authors and Affiliations

W. Wołczyński
A.W. Bydałek
Z. Lipnicki
A.A. Ivanova
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Abstract

The Structural Peclet Number has been estimated experimentally by analyzing the morphology of the continuously cast brass ingots. It

allowed to adapt a proper development of the Ivantsov’s series in order to formulate the Growth Law for the columnar structure formation

in the brass ingots solidified in stationary condition. Simultaneously, the Thermal Peclet Number together with the Biot, Stefan, and

Fourier Numbers is used in the model describing the heat transfer connected with the so-called contact layer (air gap between an ingot and

crystallizer). It lead to define the shape and position of the s/l interface in the brass ingot subjected to the vertical continuous displacement

within the crystallizer (in gravity). Particularly, a comparison of the shape of the simulated s/l interface at the axis of the continuously cast

brass ingot with the real shape revealed at the ingot axis is delivered. Structural zones in the continuously cast brass ingot are revealed: FC

– fine columnar grains, C – columnar grains, E – equiaxed grains, SC – single crystal situated axially.

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Authors and Affiliations

A.A. Ivanova
Z. Lipnicki
P. Kwapisiński
W. Wołczyński
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Abstract

A brief description of the innovative mathematical method for the prediction of CET – localization in solidifying copper and copper alloys’ ingots is presented. The method is to be preceded by the numerical simulation of both temperature field and thermal gradient filed. All typical structural zones were revealed within the copper and copper alloys’ massive ingots or rods manufactured by continuous casting. The role of thermal gradient direction for the single crystal core formation has been enlightened. The definition for the index describing proportion between volume fraction of the columnar structure and volume fraction of the equiaxed structure has been formulated by means of the interpretation of some features of the liquidus isotherm velocity course. An attempt has been undertaken to apply the developed mathematical method for the structural zones prediction in the rods solidifying under industrial conditions. An industrial application has been shown, that is, it was explained why the innovative rods should be assigned to the overhead conductors in the electric tractions.
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Authors and Affiliations

P. Kwapisiński
1
ORCID: ORCID
W. Wołczyński
2
ORCID: ORCID

  1. KGHM Polska Miedź S.A., M. Skłodowskiej-Curie 48, 59-301 Lubin, Poland
  2. Institute of Metallurgy and Materials Science, W. Reymonta 25, 30-059 Kraków, Poland

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