Crystal Orientation Relationships among Acicular Ferrite, Oxide and the Austenite Matrix in a Steel Weld Metal

Abstract:

Acicular ferrite (AFα) formed on oxide particles in steel weld metals has a positive effect on toughness at low temperature. Good lattice coherency between AFα and oxide is one of the proposed reasons for promotion of AFα formation. Lattice coherency is affected by crystal structure of oxide and crystal orientation relationship (OR) between oxide and AFα. In the present study, ORs among AFα, oxide and γFe are investigated in a low carbon steel weld metal. Cube-cube (C-C) OR is observed between γFe and the oxide. It is probable that the oxide liquefied at high temperature, and then crystalized having the C-C OR with the surrounding γFe during cooling in welding process. Near Kurdjumov-Sachs (K-S) and near Baker-Nutting (B-N) ORs are observed between γFe/AFα and oxide/AFα, respectively. The misorientation from the B-N OR is larger than that from the K-S OR just after nucleation of AFα. This implies that AFα forms satisfying a near K-S OR with γFe essentially. It is supposed that formation of both the C-C (γFe/oxide) and near K-S (AFα/γ) ORs results in apparent formation of the near B-N OR between oxide and AFα.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 1014-1018
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.1014
• Online since: January 2021
• Authors: Hidenori Nako*, Yong Jie Zhang, Goro Miyamoto, Tadashi Furuhara
• Keywords: Acicular Ferrite, Crystal Orientation Relationship, Oxide Metallurgy, Weld Metal

References

[1] J.C.F. Jorge, I.S. Bott, L.F.G. Souza, M.C. Mendes, L.S. Araújo, G.M. Evans, Mechanical and microstructural behavior of C-Mn steel weld deposits with varying titanium contents, J. Mater. Research Tech. 8 (2019) 4659-4671.

DOI: 10.1016/j.jmrt.2019.08.010

[2] L-E. Svensson, B. Gretoft, Microstructure and Impact Toughness of C-Mn Weld Metals, Weld. J. 69 (1990) 464s-461s.

[3] T. Yamada, H. Terasaki, Y. Komizo, Relation between inclusion surface and acicular ferrite in low carbon low alloy steel weld, ISIJ Int. 49 (2009) 1059-1062.

DOI: 10.2355/isijinternational.49.1059

[4] A.R. Mills, G. Thewlis, J.A. Whiteman Nature of inclusions in steel weld metals and their influence on formation of acicular ferrite, Mater. Sci. Technol. 3 (1987) 1051-1061.

DOI: 10.1179/mst.1987.3.12.1051

[5] J.M. Gregg, H.K.D.H. Bhadeshia. Bainite nucleation from mineral surfaces, Acta Metall. Mater. 42 (1994) 3321-3330.

DOI: 10.1016/0956-7151(94)90464-2

[6] J.M. Gregg, H.K.D.H. Bhadeshia, Solid-state nucleation of acicular ferrite on minerals added to molten steel, Acta Metall. Mater, 45 (1997), 739-748.

DOI: 10.1016/s1359-6454(96)00187-5

[7] Y. Okazaki, H. Ishida, K. Suenaga, T. Hidaka: Weld. Int., 26 (2012), 593.

[8] C. Blais, G. L'Esperance, G.M. Evans, Characterisation of inclusions found in C-Mn steel welds containing titanium, Sci. Tech. Weld. Joining 4 (1999) 143-150.

DOI: 10.1179/136217199101537680

[9] A.R. Mills, G. Thewlis, J.A. Whiteman, Nature of inclusions in steel weld metals and their influence on formation of acicular ferrite, Mater. Sci. Technol. 3 (1987) 1051-1061.

DOI: 10.1179/mst.1987.3.12.1051

[10] C. Lee, S. Nambu, J. Inoue, T. Koseki, Ferrite Formation Behaviors from B1 Compounds in Steels, ISIJ Int. 51 (2011) 2036-2041.

DOI: 10.2355/isijinternational.51.2036

[11] H. Nako, H. Hatano, O. Yoshitomi, K. Yamashita, M. Otsu, Crystal orientation relationships between acicular ferrite, oxide, and the austenite matrix, ISIJ Int. 54 (2014) 1690-1696.

DOI: 10.2355/isijinternational.54.1690

[12] A. Takada, Y. Komizo, H. Terasaki, T. Yokota, K. Oi, K. Yasuda, Crystallographic Analysis for Acicular Ferrite Formation in Low Carbon Steel Weld Metals, Q. J. Jpn. Weld. Soc. 31 (2013) 33-40.

DOI: 10.1080/09507116.2014.921042

[13] H.K.D.H. Bhadeshia and L.E. Svensson: Mathematical Modelling of Weld Phenomena, The Institute of Materials, London, (1993) 109.