Abstract
Inclusions in Al-killed steel with [S] of about 0.0060 to 0.0070 mass pct were characterized and discussed, evaluating the combined effects of basic slag refining and Ca treatment in ladle, together with reoxidation of liquid steel in casting tundish. Inclusions were changed from Al2O3 to MgO-Al2O3 spinel and then to MgO-Al2O3-CaO during basic slag refining. After Ca treatment, many (MgO-Al2O3) + CaS inclusions were formed, featuring the coexistence of MgO-Al2O3 and CaS to form a dual-phased structure. In the following Ar blowing, the number density of (MgO-Al2O3) + CaS inclusions and pure CaS increased obviously, which implied that [Ca] preferentially reacted with [S] rather than [O] in steel. Reoxidation in casting tundish caused the pickup of oxygen in steel, and the rise of total oxygen (T.O) was 0.0002 mass pct; even 55t steel has been poured. As a result, the content of CaO in inclusions increased and MgO-Al2O3-CaO inclusions were formed again. Thermodynamic calculations revealed that the driving force was strong for the formation of CaS-based inclusions. Higher carbon content in steel would help to reduce oxygen content while enhancing the activity of [S] in steel, which further stabilized the existence of CaS-based inclusions. Therefore, inclusions were mostly the solid (MgO-Al2O3) + CaS dual-phase ones, without the formation of liquid calcium aluminates. Contents of CaS and CaO in inclusions were affected by the [mass pct S]/[mass pct O] ratio, which was calculated as about 4.58 K and 5.34 K at 1873 K and 1823 K, respectively. This finding implied that lower oxygen was not favorable to prevent the solid inclusions in the calcium treatment of high carbon special steel.
Similar content being viewed by others
References
C. Shi, X. Chen, H. Guo, Z. Zhu, and X. Sun: Metall. Mater. Trans. B, 2013, vol. 44B, pp. 378–89.
J.H. Park and H. Todoroki: ISIJ Int., 2010, vol. 50, pp. 1333–46.
M. Jiang, X.H. Wang, B. Chen, and W.J. Wang: ISIJ Int., 2008, vol. 48, pp. 885–90.
J.H. Park: Metall. Mater. Trans. B, 2007, vol. 38B, pp. 657–63.
Y. Ehara, S. Yokoyama, and M. Kawakami: Tetsu-to-Hagané, 2007, vol. 93, pp. 475–82.
J.H. Park and D.S. Kim: Metall. Mater. Trans. B, 2005, vol. 36B, pp. 495–502.
H. Todoroki and K. Mizuno: ISIJ Int., 2004, vol. 44, pp. 1350–57.
H. Todorki and K. Mizuno: Iron Steelmaker Trans., 2003, vol. 61B, pp. 60–68.
G. Okuyama, K. Yamaguchi, S. Takeuchi, and K.I. Sorimachi: ISIJ Int., 2000, vol. 40, pp. 121–28.
T. Nishi and K. Shinme: Tetsu-to-Hagané, 1998, vol. 84, pp. 837–43.
H. Itoh, M. Hino, and S. Ban-Ya: Metall. Mater. Trans. B, 1997, vol. 28B, pp. 953–56.
J.W. Kim, S.K. Kim, D.S. Kim, Y.D. Lee, and P.K. Yang: ISIJ Int., 1996, vol. 36 (Suppl.), pp. S140–S143.
Z. Deng and M. Zhu: ISIJ Int., 2013, vol. 53, pp. 450–58.
M. Jiang, X.H. Wang, B. Chen, and W.J. Wang: ISIJ Int., 2010, vol. 50, pp. 95–104.
G.W. Yang, X.H. Wang, F.X. Huang, D. Yang, P. Wei, and X. Hao: Metall. Mater. Trans. B, 2014, vol. 46B, pp. 145–54.
S.F. Yang, J.S. Li, Z. F. Wang, J. Li, and L. Lin: Metall. Mater. Trans. B, 2011, vol. 18B, pp. 18–23.
N. Verma, P.C. Pistorius, R.J. Fruehan, M. Potter, M. Lind, and S.R. Story: Metall. Mater. Trans. B, 2011, vol. 42B, pp. 720–29.
N. Verma, P.C. Pistorius, R.J. Fruehan, M. Potter, M. Lind, and S. Story: Metall. Mater. Trans. B, 2011, vol. 42B, pp. 711–19.
N. Verma, P.C. Pistorius, and R.J. Fruehan: Iron Steel Technol., 2010, vol. 7, pp. 189–97.
E.B. Pretorius, H.G. Oltmann, and T. Cash: Iron Steel Technol., 2010, vol. 7, pp. 31–44.
M. Lind and L. Holappa: Metall. Mater. Trans. B, 2010, vol. 41B, pp. 359–66.
A. Ghosh: Trans. Ind. Inst. Met., 2008, vol. 61, pp. 473–75.
Y. Ito, S. Nara, Y. Kato, and M. Suda: Tetsu-to-Hagané, 2007, vol. 93, pp. 355–61.
S.K. Choudhary and S. Chandra: ISIJ Int., 2007, vol. 47, pp. 190–92.
J.H. Park, D.S. Kim, and S.B. Lee: Metall. Mater. Trans. B, 2005, vol. 36B, pp. 67–73.
G. Ye, P. Jonsson, and T. Lund: ISIJ Int., 1996, vol. 36 (Suppl.), pp. S105–S108.
Y. Kusano, Y. Kawauchi, M. Wajima, K. Sugawara, M. Yoshida, and H. Hayashi: ISIJ Int., 1996, vol. 36 (Suppl.), pp. S77–S80.
Y. Ito, M. Suda, Y. Kato, H. Nakato, and K. Sorimachi: ISIJ Int., 1996, vol. 36 (Suppl.), pp. S148–S150.
Y. Higuchi, M. Numata, S. Fukagawa, and K. Shinme: Tetsu-to-Hagané, 1996, vol. 82, pp. 671–76.
Y. Highchi, M. Numata, S. Fukagawa, and K. Shinme: ISIJ Int., 1996, vol. 36 (Suppl.), S151–S154
M. Imagumbai and T. Takeda: ISIJ Int., 1994, vol. 34, pp. 574–83.
D. Janke, Z. Ma, P. Valentin, and A. Heinen: ISIJ Int., 2000, vol. 40, pp. 31–39.
G. Xu, Z. Jiang, and Y. Li: Metall. Mater. Trans. B, 2016, vol. 47B, pp. 2411–20.
Y. Guo, S.P. He, G. Chen, and Q. Wang: Metall. Mater. Trans. B, 2016, vol. 47B, pp. 2549–57.
F. Jiang, G. Cheng, G. Qian, Y. Xie, Q. Rui, and L. Yang: Steel Res. Int., 2013, vol. 84B, pp. 554–59.
B. Korousic, F. Tehovnik, and B. Arh: Steel Res., 2001, vol. 72, pp. 35–39.
N. Verma, P.C. Pistorius, R.J. Fruehan, M.S. Potter, H.G. Oltmann, and E.B. Pretorius: Metall. Mater. Trans. B, 2012, vol. 43B, pp. 830–40.
C.W. Seo, S.H. Kim, S.K. Jo, M.O. Suk, and S.M. Byun: Metall. Mater. Trans. B, 2010, vol. 41B, pp. 790–97.
M. Numata and Y. Higuchi: Tetsu-to-Hagané, 2011, vol. 97, pp. 259–65.
S.K. Choudhary and A. Ghosh: ISIJ Int., 2008, vol. 48, pp. 1552–59.
L. Holappa, M. Hämäläinen, M. Liukkonen, and M. Lind: Iron Steelmaking, 2003, vol. 30, pp. 111–15.
Y. Wang, M. Valdez, and S. Sridhar: Metall. Mater. Trans. B, 2002, vol. 33B, pp. 625–32.
M. Numata, Y. Higuchi, and S. Fukagawa: Tetsu-to-Hagané, 1998, vol. 84, pp. 159–64.
B. Ozturk and E.T. Turkdogan: Met. Sci., 1984, vol. 18, pp. 306–09.
B. Ozturk and E.T. Turkdogan: Met. Sci., 1984, vol. 18, pp. 299–305.
X.W. Zhang, L.F. Zhang, W. Yang, Y. Liu, and Y.C. Dong: Metall. Mater. Trans. B, 2017, vol. 48B, pp. 701–12.
G.W. Yang and X.H. Wang: ISIJ Int., 2015, vol. 55, pp. 126–33.
I.H. Jung, S.A. Decterov, and A.D. Pelton: ISIJ Int., 2004, vol. 44, pp. 527–36.
G.W. Yang, X.H. Wang, F.X. Huang, W.J. Wang, Y.Q. Yin, and C.X. Tang: Steel Res. Int., 2014, vol. 85, pp. 784–92.
Steelmaking Data Sourcebook, The Japan Society for the Promotion of Science, Gordon & Breach Science Publishers, New York, NY, 1988.
G.K. Sigworth and J.F. Elliott: Met. Sci., 1974, vol. 8, p. 298
R.H. Rein and J. Chipman: Trans. TMS-AIME, 1965, vol. 233, p. 415.
H. Suito and R. Inoue: ISIJ Int., 1996, vol. 36, pp. 528–36.
Acknowledgment
The authors are thankful for the support of China National Science Funding (Grant No. 51304013) during this research.
Author information
Authors and Affiliations
Corresponding author
Additional information
Manuscript submitted November 8, 2017.
Rights and permissions
About this article
Cite this article
Hou, ZW., Jiang, M., Yang, EJ. et al. Inclusion Characterization in Aluminum-Deoxidized Special Steel with Certain Sulfur Content Under Combined Influences of Slag Refining, Calcium Treatment, and Reoxidation. Metall Mater Trans B 49, 3056–3066 (2018). https://doi.org/10.1007/s11663-018-1365-x
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11663-018-1365-x