Kinetics of Austenite Grain Growth during a Continuous Heating of a Niobium Microalloyed Steel

Abstract:

Grain growth is a thermally activated process in which the average grain size increases as temperature and time increases. The driving force for grain growth results from the decrease in the free energy associated with the reduction in total grain boundary energy. There are several known factors that influence the migration of grain boundaries such as second phase particles precipitated in the matrix and the solute elements segregated at grain boundaries. The austenite grain boundaries are revealed using the thermal etching method. Carbon extraction replicas were prepared to determine the composition and size of precipitates present in the matrix. In this work, the evolution of the average prior austenite grain size (PAGS) of a low carbon steel microalloyed with niobium is studied as a function of temperature and heating rate. Austenite grains show a two-stage growth. It has been found that as heating rate increases, the grain coarsening temperature (TGC) increases and the grain size at that temperature decreases. TGC temperature lies around 40-60°C below the temperature for complete dissolution of carbonitrides (TDISS).

• Periodical: Materials Science Forum (Volumes 467-470)
• Pages: 929-934
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.467-470.929
• Online since: October 2004
• Authors: David San Martín, Francisca G. Caballero, Carlos Capdevila, C. Carcía de Andrés
• Keywords: Continuous Heating, Grain Growth, Microalloyed Steel

References

[1] H. Ohtani, F. Terasaki, T. Kunitake: Trans. ISIJ, Vol. 12, 1972, p.118.

[2] N. J. Petch: J. of the ISIJ, Vol. 174, 1953, p.25.

[3] A. Grange: Trans. ASM, Vol. 59, 1966, p.26.

[4] N.T. Baker: Future Developments of Metals and Ceramics (Institute of Materials, edited by J.A. Charles, G.W. Greenwood and G.C. Smith, London, 1992), p.75.

[5] P.K. Amin and F.B. Pickering: Thermomechanical processing of microalloyed austenite, (TMS-AIME, Warrendale, PA, 1982), p.1.

[6] C. García de Andrés, M. J. Bartolomé, C. Capdevila, D. San Martín, F. G. Caballero, V. López: Mater. Charact., Vol. 46, 2001, p.389.

[7] ASTM E 112-96: Standard Test Methods for Determining Average Grain Size, p.227.

[8] G. R. Booker, J. Norbury: British J. of Appl. Phys., Vol. 8, 1957, p.109.

[9] C. P. Scott, D. Chaleix, P. Barges, V. Rebischung: Scripta Mater., Vol. 47, 2002, p.845.

DOI: 10.1016/s1359-6462(02)00219-1

[10] S. G. Hong, H. J. Jun, K. B. Kang, C. G. Park: Scripta Mater., Vol. 48, 2003, p.1201.

[11] A. Fukami: Jeol News, July, 1967, p.5.

[12] R. Coladas, J. Masounave, G. Guérin, And J. -P. Bailón, Met. Sci., November, 1977, p.509.

[13] L.J. Cuddy and J. C. Raley: Metall. Trans. A, Vol. 14, 1983, p. (1989).

[14] C. Zener, quoted by C. S. Smith: Trans. AIME, Vol. 175, 1948, p.47.

[15] I.M. Lifshitz and V.V. Slyozov: J. of Phys. Chem. Of Solids, Vol. 19, 1961, p.35.

[16] E.J. Palmiere, C.I. Garcia and A.J. DeArdo: Metall and Mater. Trans. A, Vol. 25, 1994, p.277.

[17] H. Davies: MTDATA (National Physical Laboratory, Teddington, UK, 2003).

[18] T. Gladman and F. B. Pickering: J. of the ISI, Vol. 205, 1967, p.653.