Advertisement

Modelling Macrosegregation in Electroslag Remelted Ingots

  • D. R. Poirier
  • M. C. Flemings
  • R. Mehrabian
  • H. J. Klein
Chapter
Part of the Sagamore Army Materials Research Conference Proceedings book series (SAMC, volume 25)

Abstract

Equations for predicting flow of interdendritic liquid and macrosegregation in ingots prepared by electroslag remelting (ESR) are derived, and computer predictions of macrosegregation based on these equations are compared with macrosegregation measured in experimental ingots.

Agreement between calculations and experimental results is excellent. Experiments have been on model ESR ingots (65–105 mm diameter) of Sn-Pb and Al-Cu alloys; in addition, results are discussed for a nickel-base alloy produced in a laboratory ESR ingot mold with a diameter of 200 mm. The influence of the important solidification parameters such as the shape and depth of the mushy zone and the local solidification time on the macrosegregation across the ESR ingots is quantitatively demonstrated. It is shown that macrosegregation theory predicts not only surface-to-center variations in compositions, but also predicts conditions under which a severe type of segregation, called “freckles”, forms in ESR ingots.

A method of minimizing macrosegregation is demonstrated whereby ingot rotation alters interdendritic flow behavior and therefore macrosegregation. Modest rotational speeds eliminate “freckles” and minimize surface-to-center type segregation, as well. It is also suggested that macrosegregation theory should be considered during the alloy design stage in that alloy constitution can possibly be adjusted to produce ESR ingots with no “freckles” and minimum segregation.

Recommendations to improve the “state of the art” in modelling macrosegregation are given. For example, the effect of convection of the liquid pool should be examined and possibly included in future models. In addition, the effect of the interdendritic liquid flow should be included in the energy equation when it is applied to the mushy zone of large ingots, and possibly, the electromagnetic force field should be included in the equation of motion in the mushy zone. The selections of values of permeability used for macro-segregation simulation are also discussed and compared to permeability measured by experiment.

Keywords

Mushy Zone Versus Versus Versus Versus Versus Liquid Pool Interdendritic Liquid Ingot Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    S. G. Arwidson, “Technico-Economic Appraisal of a Large Tonnage ESR Installation,” in Electroslag Refining, Iron and Steel Institute, London, 1973, pp. 157–162.Google Scholar
  2. 2.
    H. Fredriksson and O. Jarleborg, J. of Metals, September, 1971, p. 32.Google Scholar
  3. 3.
    J. O. Ward and R. C. Hambleton, “Production Experience of Electroflux Remelting of Nickel-Base Superalloys,” in Electroslag Refining, Iron and Steel Institute, London, 1973, pp. 80–88.Google Scholar
  4. 4.
    M. Basaran, T. Z. Kattamis, R. Mehrabian, and M. C. Flemings, “A Study of the Heat and Fluid Flow in Electroslag Remelting,” Army Materials and Mechanics Research Center, Contract No. DAAG 46–73-C-0088, April, 1974.Google Scholar
  5. 5.
    Yu M. Mironov and M. M. Klyuev, Russian Metallurgy, 1968, No. 2, pp. 72–76.Google Scholar
  6. 6.
    M. A. Maulvault, “Temperature and Heat Flow in the Electroslag Remelting Process,” Ph.D. Thesis, Department of Materials Science and Engineering, M.I.T., 1971.Google Scholar
  7. 7.
    A. S. Ballatityne and A. Mitchell, Ironmaking and Steelmaking, 1977, No. 4, pp. 222–239.Google Scholar
  8. 8.
    R. C. Sun, J. W. Pridgeon, “Predicting Pool Shapes in a Laboratory Electroslag Remelting Process,” Union Carbide Corporation, Materials System Division, Technology Department, Kokomo, Indiana, September, 1969, Report No. 7649.Google Scholar
  9. 9.
    A Mitchell, S. Joshi, Met. Trans., V. 4, 1973, pp. 631–642.CrossRefGoogle Scholar
  10. 10.
    B. Z. Paton et al., “Calculation of Temperature Fields in Plate Ingots and in Ingot-Slabs of ESR,” in Fifth International Symposium on ESR Process, Carnegie-Mellon University, Pittsburgh, October, 1974, p. 323.Google Scholar
  11. 11.
    S. D. Ridder, F. C. Reyes, S. Chakravorty, R. Mehrabian, J. D. Nauman, J. H. Chen and H. J. Klein, “Steady State Segregation and Heat Flow in ESR,” to be published in Met. Trans. B., 1978.Google Scholar
  12. 12.
    S. Kou, D. R. Poirier, and M. C. Flemings, “Macrosegregation in Electroslag Remelted Ingots,” in Proceedings of the Electric Furnace Conference, Iron and Steel Society of AIME, December, 1977.Google Scholar
  13. 13.
    S. Kou, D. R. Poirier and M. C. Flemings, “Macrosegregation in Rotated Remelted Ingots,” to be published in Met. Trans. B, 1978.Google Scholar
  14. 14.
    M. C. Flemings, G. E. Nereo, Trans. Met. Soc., AIME, V. 239, 1967, pp. 1449–1461.Google Scholar
  15. 15.
    M. D. Flemings, R. Mehrabian and G. E. Nereo, Trans. Met. Soc., AIME, V. 242, 1968, pp. 41–49.Google Scholar
  16. 16.
    M. C. Flemings and G. E. Nereo, Trans. Met. Soc., AIME, V. 242, 1968, pp. 50–55.Google Scholar
  17. 17.
    R. Mehrabian and M. C. Flemings, Trans. Met. Soc., AIME, V. 245, 1969, p. 2347.Google Scholar
  18. 18.
    R. Mehrabian, M. A. Keane and M. C. Flemings, Met. Trans., V. 1, 1970, p. 1209.Google Scholar
  19. 19.
    R. Mehrabian, M. A. Keane and M. C. Flemings, Met. Trans. V. 1, 1970, p. 3238.Google Scholar
  20. 20.
    M. Keane, Sc.D. Dissertation, Massachusetts Institute of Technology, 1973.Google Scholar
  21. 21.
    R. Mehrabian, J. J. Burke, M. C. Flemings and A. E. Gorum, Eds., Solidification Technology, Brook Hill Publishing Company, Chestnut Hill, Mass., 1974.Google Scholar
  22. 22.
    M. C. Flemings, Scandinavian J. of Metallurgy, V. 5, 1976, p. 1.Google Scholar
  23. 23.
    A. H. Dilawari and J. Szekely, Met. Trans. B, V. 9B, 1978, pp. 77–87.CrossRefGoogle Scholar
  24. 24.
    E. Scheil, Metallforsch., V. 2, 1947, p. 69.Google Scholar
  25. 25.
    J. S. Kirkaldy and W. V. Youdelis, Trans. AIME, V. 212, 1958, p. 833.Google Scholar
  26. 26.
    S. Kou, “Macrosegregation in Electroslag Remelted Ingots,” Ph.D. Thesis, Department of Materials Science and Engineering, Massachusetts Institute of Technology, 1978.Google Scholar
  27. 27.
    D. R. Poirier, S. Kou, T. Fujii and M. C. Flemings, “Electroslag Remelting,” Contract No. DAAG46–74-C-0120, Army Materials and Mechanics Research Center, Watertown, Mass., AMMRC TR78–28, June, 1978.Google Scholar
  28. 28.
    P. O. Meilberg and H. Sandberg, Scand. J. Metallurgy, V. 2, 1973, pp. 83–86.Google Scholar
  29. 29.
    R. H. Frost, “Solidification of Electroslag Remelted Low Alloy Steel Ingots,” Army Materials and Mechanics Research Center, Watertown, Mass., AMMRC TR77–20, October, 1977.Google Scholar
  30. 30.
    R. J. McDonald and J. D. Hunt, TMS-AIME, V. 245, 1969, p. 1993.Google Scholar
  31. 31.
    S. M. Copley, A. F. Giamei, S. M. Johnson and J. F. Hornbecker, Met. Trans., V. 1, 1970, p. 2193.CrossRefGoogle Scholar
  32. 32.
    T. Fujii, D. R. Poirier and M. C. Flemings, “Macrosegregation in a Multicomponent Low Alloy Steel,” submitted for publication to Met. Trans., June, 1978.Google Scholar
  33. 33.
    K. Suzuki and T. Miyamoto, Japan Society for the Promotion of Sciences, Nineteenth Committee, 1972, No. 9478.Google Scholar
  34. 34.
    J. Lagrange, J. Delorme and P. Bocquet, “Influence du Mode d’Elaboration sur la Segregation des Gros Lingots de Forge,” 20eme Colloque de Metallurgie, Saclay, Juin, 1977.Google Scholar
  35. 35.
    T. W. Caldwell, A. J. Campagna, M. C. Flemings and R. Mehrabian, Met. Trans. B, V. 8B, 1977, pp. 261–270.CrossRefGoogle Scholar
  36. 36.
    T. S. Piwonka, M. C. Flemings, “Pore Formation in Solidification,” Trans. Met. Soc. AIME, V. 236, 1966, pp. 1157–1165.Google Scholar
  37. 37.
    D. Apelian, M. C. Flemings, R. Mehrabian, “Specific Permeability of Partially Solidified Networks of Al-Si Alloys,” Met. Trans., V. 5, 1974, pp. 2533–2537.CrossRefGoogle Scholar
  38. 38.
    T. S. Piwonka, Sc.D. Thesis, Department of Metallurgy, Massachusetts Institute of Technology, 1964.Google Scholar
  39. 39.
    N. Streat and F. Weinberg, Met. Trans. B, V. 7B, 1976, p. 417.CrossRefGoogle Scholar
  40. 40.
    A. H. Dilawari and J. Szekely, Met. Trans. B, V. 8B, 1977, pp. 227–236.CrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1981

Authors and Affiliations

  • D. R. Poirier
    • 1
  • M. C. Flemings
    • 2
  • R. Mehrabian
    • 3
  • H. J. Klein
    • 4
  1. 1.University of ArizonaTucsonUSA
  2. 2.Massachusetts Institute of TechnologyCambridgeUSA
  3. 3.University of IllinoisUrbanaUSA
  4. 4.Stellite DivisionCabot Corp.KokomoUSA

Personalised recommendations