Metallurgical and Materials Transactions B

, Volume 46, Issue 5, pp 2198–2207 | Cite as

Formation Mechanism of SiO2-Type Inclusions in Si-Mn-Killed Steel Wires Containing Limited Aluminum Content

  • Kunpeng Wang
  • Min Jiang
  • Xinhua Wang
  • Ying Wang
  • Haoqian Zhao
  • Zhanmin Cao
Article

Abstract

The origin, formation mechanism, and evolution of SiO2-type inclusions in Si-Mn-killed steel wires were studied by pilot trials with systematical samplings at the refining ladle, casting tundish, as-cast bloom, reheated bloom, and hot-rolled rods. It was found that the inclusions in tundish were well controlled in the low melting point region. By contrast, MnO-SiO2-Al2O3 inclusions in the as-cast bloom were with compositions located in the primary region of SiO2, and most CaO-SiO2-Al2O3-MnO inclusions lied in primary phase region of anorthite. Therefore, precipitation of SiO2 particles in MnO-SiO2-Al2O3 inclusions can be easier than in CaO-SiO2-Al2O3-MnO inclusions to form dual-phase inclusions in the as-cast bloom. Thermodynamic calculation by the software FactSage 6.4 (CRCT-ThermFact Inc., Montréal, Canada) showed that mass transfer between liquid steel and inclusions resulted in the rise of SiO2 content in inclusions from tundish to as-cast bloom and accelerated the precipitation of pure SiO2 phase in the formed MnO-SiO2-Al2O3 inclusions. As a result, the inclusions characterized by dual-phase structure of pure SiO2 in MnO-SiO2-Al2O3 matrix were observed in both as-cast and reheated blooms. Moreover, the ratio of such dual-phase SiO2-type inclusions witnessed an obvious increase from 0 to 25.4 pct before and after casting, whereas it changed little during the reheating and rolling. Therefore, it can be reasonably concluded that they were mainly formed during casting. Comparing the evolution of the inclusions composition and morphology in as-cast bloom and rolled products, a formation mechanism of the SiO2-type inclusions in wire rods was proposed, which included (1) precipitation of SiO2 in the formed MnO-SiO2-Al2O3 inclusion during casting and (2) solid-phase separation of the undeformed SiO2 precipitation from its softer MnO-SiO2-Al2O3 matrix during multipass rolling.

References

  1. 1.
    S. Maede, T. Soejima, T. Saito, H. Matsumoto, H. Fujimoto, and T. Mimura: 72 nd Steelmaking Conference Proceedings, Chicago, IL, 1989, pp. 379–85.Google Scholar
  2. 2.
    G.M. Fauling: Ironmak. Steelmak., 1999, vol. 26, pp. 29–36.Google Scholar
  3. 3.
    Y.B. Kang, and H.G. Lee: ISIJ Int., 2004, vol. 44, pp. 1006-15.CrossRefGoogle Scholar
  4. 4.
    K. Karihara: Kobelco Tech. Rev., 2011, vol. 30, pp. 62-65.Google Scholar
  5. 5.
    J.D. Seo, Y.T. Kim, and D.H. Kim: 5 th International Congress on the Science and Technology of Steelmaking, Dresden, 2012, pp. 1250–54.Google Scholar
  6. 6.
    S.H. Chen, M. Jiang, X.F. He, and X.H. Wang: Int. J. Miner. Metall. Mater., 2012, vol. 19, pp. 490-8.CrossRefGoogle Scholar
  7. 7.
    J.S. Park, and J.H. Park: Metall. Mater. Trans. B, 2014, vol. 45, pp. 953-60.CrossRefGoogle Scholar
  8. 8.
    R. Kiessling: Non-Metallic Inclusions in Steel, Part I Inclusions Belonging to the Pseudo-Ternary MnO-SiO 2-Al 2 O 3 and Related System, The Metals Society, London, U.K., 1968, pp. 17-25.Google Scholar
  9. 9.
    J. Kawahara, K. Watanabe, T. Banno, and M. Yoshida: Wire J. Int., 1992, vol. 25, pp. 55-61.Google Scholar
  10. 10.
    T. Sugimura, S. Kimura, K. Sakamoto, A. Yoshida, and T. Inoue: Patent China CN 101443468 B Kobe Steel, Ltd., 2012.Google Scholar
  11. 11.
    S. Feichtinger, S.K. Michelic, Y.B. Kang, and C. Bernhard: J. Am. Ceram. Soc., 2014, vol. 97, pp. 316-25.CrossRefGoogle Scholar
  12. 12.
    H. Shibata, K. Kimura, T. Kimura, T. Tanaka, and S. Kitamura: ISIJ Int., 2011, vol. 51, pp. 1944-50.CrossRefGoogle Scholar
  13. 13.
    H. Shibata, T. Tanaka, S. Kitamura, and T. Kimura: Ironmaking Steelmaking, 2010, vol. 37, pp. 522-8.CrossRefGoogle Scholar
  14. 14.
    W. Choi, H. Matsuura, and F. Tsukihashi: ISIJ Int., 2011, vol. 51, pp. 1951-6.CrossRefGoogle Scholar
  15. 15.
    K.H. Kim, S.J. Kim, H. Shibata, and S. Kitamura: ISIJ Int., 2014, vol. 54, pp. 2144-53.CrossRefGoogle Scholar
  16. 16.
    X.H. Wang, X.G. Li, F.X. Huang, H.B. Li, and J. Yang: Steel Res. Int., 2014, vol. 85, pp. 155-63.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2015

Authors and Affiliations

  • Kunpeng Wang
    • 1
  • Min Jiang
    • 1
  • Xinhua Wang
    • 1
  • Ying Wang
    • 2
  • Haoqian Zhao
    • 2
  • Zhanmin Cao
    • 1
  1. 1.School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijingP.R. China
  2. 2.Xingtai Iron & Steel Corp., Ltd.HebeiP.R. China

Personalised recommendations