Abstract
Low and medium carbon steels experience multiple phase transformations during solidification and subsequent cooling. The sequence, extent, and nature of the different transformations have a significant bearing on the microstructural evolution that occurs in the steel. The change in microstructure with temperature is very important, since it may influence the hot ductility of the steel during casting and/or rolling and the subsequent response of the material to thermoprocessing. The aim of this investigation was to gain a better understanding of the development of the as-cast structure in low and medium carbon steels. Of particular interest is the origin of the large austenite grains frequently associated with poor hot ductility. Interrupted and isothermal solidification experiments were therefore conducted to study the nonequilibrium and near-equilibrium structures which form at different stages of the freezing process. The results of the investigation established delta-ferrite as the primary solidifying phase in low carbon steels. Austenite forms as the secondary phase by nucleation at the solidification (delta-ferrite) boundaries. While excessive austenite grain coarsening is suppressed by the coexistence of the second phases delta-ferrite or liquid, this suppression occurs over only a limited temperature range, just below the peritectic temperature. Subsequent cooling leads to very large austenite grains, ranging up to 5 mm in diameter, in steels of low carbon content.
Similar content being viewed by others
References
W.B. Morrison and J.A. Chapman:Phil. Trans. R. Soc. London, 1976, vol. A-282, p. 289.
F.B. Pickering:Proc. Microalloying 75, Union Carbide Corporation, New York, NY, 1977, pp. 9–31.
G.R. Speich, L.J. Cuddy, C.R. Gordon, and A.J. DeArdo:Proc. Phase Transformations in Ferrous Alloys, TMS-AIME, Warrendale, PA, 1984, pp. 341–89.
A.J. DeArdo:Can. Metall. Q., 1988, vol. 27, pp. 141–54.
A.J. DeArdo:Proc. Thermec 88, Iron Steel Institute of Japan, Tokyo, 1988, pp. 20–29.
H.G. Suzuki, S. Nishimura, and S. Yamaguchi:Trans. Iron Steel Inst. Jpn., 1982, vol. 22, pp. 48–55.
J.Y. Fu, C.I. Garcia, S. Pytel, and A.J. DeArdo:Proc. Processing Microstructure and Properties of HSLA Steels, TMS-AIME, Warrendale, PA, 1988, pp. 27–38.
L. Schmidt and A. Josefsson:Scand. J. Metall., 1974, vol. 3, pp. 193–99.
I. Tamura, C. Ouchi, T. Tanaka, and H. Sekine:Thermomechanical Processing of High Strength Low Alloy Steels, Butterworth's, London, 1988, pp. 233–34.
J.G. Williams, C.R. Killmore, J.R. Barrett, and A.K. Church:Proc. Processing, Microstructure and Properties of HSLA Steels, TMS-AIME, Warrendale, PA, 1988, pp. 133–52.
E.T. Turkdogan and R.A. Grange:J. Iron Steel Inst., 1970, vol. 208, pp. 482–94.
T.Z. Kattamis and M.C. Flemings:TMS-AIME, 1965, vol. 233, pp. 992–99.
H. Zhang, N.S. Pottore, C.I. Garcia, M.G. Burke, and A.J. DeArdo:Proc. HSLA Steels—Metallurgy and Applications, ASM, Metals Park, OH, 1986, pp. 445–53.
Y. Maehara and Y. Ohmori:Mater. Sci. Eng., 1984, vol. 62, pp. 109–19.
H.G. Suzuki, S. Nishimura, J. Inamura, and Y. Nakamura:Trans. Iron Steel Inst. Jpn., 1984, vol. 24, pp. 169–77.
C. Ouchi and K. Matsumoto:Trans. Iron Steel Inst. Jpn., 1982, vol. 22, pp. 181–89.
B. Mintz and J.M. Arrowsmith:Met. Technol., 1979, vol. 6, pp. 24–32.
J.R. Wilcox and R.W.K. Honeycombe:Met. Technol., 1984, vol. 11, pp. 217–25.
K. Yamanaka, F. Terasaki, H. Ohtanl, M. Oda, and M. Yoshihara:Trans. Iron Steel Inst. Jpn., 1980, vol. 20, pp. 810–16.
T. Edvardsson, H. Fredriksson, and I. Svensson:Mater. Sci., 1976, vol. 10, pp. 298–306.
D.J. Hurtuk: Ph.D. Dissertation, Case Western Reserve University, Cleveland, OH, 1981.
H. Fredricksson:Scand. J. Metall., 1976, vol. 5, pp. 27–32.
S.V. Subramanian: McMaster University, Hamilton, ON, Canada, unpublished technical report, 1982.
Y. Maehara, K. Yasumoto, Y. Sugitani, and K. Gunji:Trans. Iron Steel Inst. Jpn., 1985, vol. 25, pp. 1045–52.
H. Zhang, N.S. Pottore, M.G. Burke, C.I. Garcia, and A.J. DeArdo:Proc. Steelmaking Conf. Iron and Steel Society, Warrendale, PA, 1986, vol. 69, pp. 377–85.
J. Chipman:Metall. Trans. A, 1972, vol. 3A, pp. 55–64.
A Guide to the Solidification of Steels, Jernkontoret, Stockholm, Sweden, 1977, p. 22.
K. Yasumoto, T. Nagamichi, Y. Maehara, and K. Gunji:Tetsu- to-Hagané, 1987, vol. 73 (14), pp. 1738–45.
K. Ishida, H. Hukai, H. Ohtani, and K. Nishizawa:Tetsu-to- Hagané, 1985, vol. 71 (4), p. 198.
B.L. Bramfitt:Metall. Trans., 1970, vol. 1, pp. 1987–95.
Author information
Authors and Affiliations
Additional information
N.S. POTTORE, formerly with the Basic Metals Processing Research Institute, Department of Materials Science and Engineering, University of Pittsburgh
Rights and permissions
About this article
Cite this article
POttore, N.S., Garcia, C.I. & DeArdo, A.J. Interrupted and Isothermal Solidification Studies of Low and Medium Carbon Steels. Metall Trans A 22, 1871–1880 (1991). https://doi.org/10.1007/BF02646512
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02646512