Abstract
In-situ spatially resolved X-ray diffraction (SRXRD) experiments were performed during gas tung-sten arc (GTA) welding of AISI 1045 C-Mn steel. Ferrite (α) and austenite (γ) phases were identified and quantified in the weld heat-affected zone (HAZ) from the real time SRXRD data. The results were compiled with weld temperatures calculated using a coupled thermal fluids model to create a phase map of the HAZ. Kinetics of the α → γ transformation during weld heating and the reverse γ → α transformation during weld cooling were extracted from the map. Superheating as high as 250 °C above the A3 temperature was observed for the α → γ phase transformation to reach completion at locations near the fusion zone (FZ) boundary. The SRXRD experiments revealed that the newly created γ phase exists with two distinct lattice parameters, resulting from the inhomogeneous distribution of carbon and manganese in the starting pearlitic/ferritic microstructure. During cooling, the reverse γ → α phase transformation was shown to depend on the HAZ location. In the fine-grained region of the HAZ, the γ → α transformation begins near the A3 temperature and ends near the A1 temperature. In this region, where the cooling rates are below 40 °C/s, the transformation occurs by nucleation and growth of pearlite. In the coarse-grained region of the HAZ, the γ → α transformation requires 200 °C of undercooling for completion. This high degree of undercooling is caused by the large grains coupled with cooling rates in excess of 50 °C/s that result in a bainitic transformation mechanism.
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References
Ø. Grong:Metallurgical Modelling of Welding, The Institute of Materials, London, 1994, ch. 1.
M.F. Ashby and K.E. Easterling:Acta Metall., 1982, vol. 30, pp. 1969–78.
J.C. Ion, K.E. Easterling, and M.F. Ashby:Acta Metall., 1984, vol. 32, pp. 1949–62.
G.S. Huppi, D.K. Matlock, and G. Krauss:Scripta Metall., 1980, vol. 14, pp. 1239–43.
J.W. Elmer, T.A. Palmer, S.S. Babu, W. Zhang, and T. DebRoy:Welding J., 2004, vol. 83 (9), pp. 244-s–253-s.
J. Wong, T. Ressler, and J.W. Elmer:J. Synchrotron Radiation, 2003, vol. 10, Part 2, pp. 154–67.
W. Zhang, G.G. Roy, J.W. Elmer, and T. DebRoy:J. Appl. Phys., 2003, vol. 93 (5), pp. 3022–33.
J.W. Elmer, J. Wong, and T. Ressler:Metall. Mater. Trans. A, 2001, vol. 32A, pp. 1175–87.
J.W. Elmer, T.A. Palmer, W. Zhang, B. Wood, and T. DebRoy:Acta Mater., 2003, vol. 51, pp. 3333–49.
W. Zhang, J.W. Elmer, and T. DebRoy:Sci. Technol. Welding Joining, 2005, vol. 10 (5), pp. 574–82.
W. Zhang, J.W. Elmer, and T. DebRoy:Scripta Mater., 2002, vol. 46, pp. 753–57.
W. Zhang, J.W. Elmer, and T. DebRoy:Mater. Sci. Eng., A, 2002, vol. 333 (1–2), pp. 320–35.
A. Kumar, S. Mishra, J.W. Elmer, and T. DebRoy:Metall. Mater. Trans. A, 2005, vol. 36A, pp. 15–22.
T.A. Palmer and J.W. Elmer:Scripta Mater., 2005, vol. 53 (5), pp. 535–40.
T.A. Palmer and J.W. Elmer:Metall. Mater. Trans. A, 2005, vol. 36A, pp. 3353–69.
S. Babu: Oak Ridge National Laboratory, Oak Ridge, TN, private communication, 2002.
B. Sundman, B. Jansson, and J. Andersson:CALPHAD, 1985, vol. 9 (2), pp. 153–90.
K. Mundra, T. DebRoy, and K. Kelkar:Num. Heat Transfer, 1996, vol. 29, pp. 115–29.
Z. Yang and T. DebRoy:Metall. Mater. Trans. B, 1999, vol. 30B, pp. 483–93.
M.W. Chase, Jr., C.A. Davies, J.R. Downey, Jr., D.J. Frurip, R.A. McDonald, and A.N. Syverud:JANAF Thermochemical Tables, 3rd ed., American Chemical Society and American institute for Physics, Washington, DC, 1985.
Smithells Metals Reference Book, 7th ed., E.A. Brandes, ed., Butterworth and Heinemann, London, 1992.
H.K.D.H. Bhadeshia, L.E. Svensson, and B. Gretoft:Acta Metall., 1985, vol. 33 (7), pp. 1271–83.
H.K.D.H. Bhadeshia:Met. Sci., 1982, vol. 16 (3), pp. 159–65.
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Elmer, J.W., Palmer, T.A. In-situ phase mapping and direct observations of phase transformations during arc welding of 1045 steel. Metall Mater Trans A 37, 2171–2182 (2006). https://doi.org/10.1007/BF02586137
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DOI: https://doi.org/10.1007/BF02586137