Inclusion Removal Mechanisms of Al-Killed 304 Low Carbon Stainless Steel Melt Using Hercynite Coated Al2O3-C Ceramic Foam Filters

Document Type : Research Paper


1 Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Najafabad, Iran

2 Advanced Materials Research Center, Materials Engineering Department, Najafabad Branch, Islamic Azad University, Najafabad, Iran; Department of Materials Science, Shahreza Branch, Islamic Azad University, Shahreza, Iran

3 Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran


Carbon bonded alumina foam filters have been successfully using for steel melt filtration. Enhancement of the filtration capacity of Al2O3-C foam filters is a key factor in order to make them applicable to be used for large steel casting parts or continuous casting of steel. In the present study, filtration performance of hercynite coated carbon bonded alumina foam filters containing 1 Wt.% of nano-TiO2 were evaluated by the exposure to an Al-killed 304 low carbon stainless steel melt. Successful impingement of steel melt into the filters revealed the filter structure strength and effectiveness under casting temperature and molten metal exposure conditions. Microstructural investigations using a field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS) analysis of the active hercynite coated filter surfaces after steel melt filtration revealed the entrapment of the oxide inclusions from the steel melt on the surface of the filter. In addition, filtration mechanisms for whiskers and dendritic Al2O3, and hercynite inclusions at different Al/oxygen activity conditions of the steel melt were proposed. To this end, the feasible potential for the application of hercynite coated Al2O3-C filters for low and ultra-low carbon steel casting processes could be promising.


Main Subjects

[1] D. Krewerth, T. Lippmann, A. Weidner, H. Biermann, "Influence of non-metallic inclusions on fatigue life in the very high cycle fatigue regime", Int. J. Fatigue, Vol. 84, 2016, pp. 40-52.
[2] O.A. Shevtsova, N.A. Zyuban, D.V. Rutskii, "Aspects of the formation of sulfide inclusions and their effect on the quality of low-alloy structural steels", Metallurgist, Vol. 54, 2011, pp. 839-844.
[3] Y. Murakami, S. Beretta, "Small defects and inhomogeneities in fatigue strength: experiments, models and statistical implications", Extremes, Vol. 2, No. 2, 1999, pp. 123-147.
[4] V.S. Dub, A.A. Safronov, M.A. Movchan, A.V. Ioffe, V.I. Tazetdinov, G.A. Zhivykh, "Effect of a secondary metallurgy technology on the types of forming nonmetallic inclusions and the corrosion resistance of steel", Russ. Metall., Vol. 12, 2016, pp. 1135-1144.
[5] L. Zhang, "Nucleation, Growth, Transport, and Entrapment of Inclusions During Steel Casting Journal of The Minerals", Metals & Materials Society, Vol. 65, 2013, pp. 1138-1144.
[6] J. Brockmeyer, L. Aubrey, "Application of ceramic foam filters in molten metal filtration",  In: Smothers WJ, ed. Appl. Ref. Ceram. Eng. Sci. Proc. 8. Westerville, Ohio: The American Ceramic Society, 1987; p.63-74.
[7] C.G. Aneziris, A. Ansorge, H. Jaunich, "New approaches of carbon bonded foam filters for filtration of large castings", Ceram. Forum Int., Vol.  85, No. 10, 2008, pp. 100-103.
[8] J. Luyten, S. Mullens, J. Cooymans, A.M. De Wilde, I. Thijs, R. Kemps, "Different methods to synthesize ceramic foams", J. Eur. Ceram. Soc., Vol. 29, No. 5, 2009, pp. 829-832.
[9] T. Schlordt, S. Schwanke, F. Keppner, T. Fey, N. Travitzky, P. Greil, "Robocasting of alumina hollow filament lattice structures", J. Eur. Ceram. Soc., Vol. 33, 2013, pp. 3243-3248.
[10] P. Colombo, "Conventional and novel processing methods for cellular ceramics", Philosophical Transactions of Royal Society A, Vol. 364, 2006, pp. 109-124.
[11] S. Ali, D. Apelian, R. Mutharasan, "Refining of aluminum and steel melts by the use of multicellular extruded ceramic filters", Can. Metall. Q., Vol. 24, No. 4, 1985, pp. 311-318.
[12] Z. Taslicukur, C. Balaban, N. Kuskonmaz, "Production of ceramic foam filters for molten metal filtration using expanded polystyrene", J. Eur. Ceram. Soc., Vol. 27, 2007, pp. 637-640.
[13] C.G. Aneziris, "Clean steel technologies based on interactions of refractory filtering materials with steel melt", J. China's Ref., Vol. 25, No. 3, 2016, pp. 1-10.
[14] M. Emmel, C.G. Aneziris, "Development of novel carbon bonded filter compositions for steel melt filtration", Ceram. Int., Vol. 38, No. 6, 2012, pp. 5165-5173.
[15] M. Emmel, C.G. Aneziris, G. Schmidt, D. Krewerth, H. Biermann, "Influence of the chemistry of surface functionalized ceramic foam filters on the filtration of alumina inclusions in steel melts", Adv. Eng. Mater., Vol. 15, No. 12, 2013, pp. 1188-1196.
[16] E. Storti, M. Emmel, S. Dudczig, P. Colombo, C.G. Aneziris, "Development of multi-walled carbon nanotubes-based coatings on carbon-bonded alumina filters for steel melt filtration", J. Eur. Ceram. Soc., Vol. 35, No. 5, 2015, pp. 1569-1580.
[17] E. Storti, S. Dudcziga, G. Schmidt, P. Colombo, C.G. Aneziris, "Short-time performance of MWCNTs-coated Al2O3-C filters in a steel melt", J. Eur. Ceram. Soc., Vol. 36, No. 3, 2016, pp. 857-866.
[18] M. Emmel, C.G. Aneziris, F. Sponza, S. Dudczig, P. Colombo, "In situ spinel formation in Al2O3-MgO-C filter materials for steel melt filtration", Ceram. Int., Vol. 40, No. 8, 2014, pp. 13507-13513.
[19] S. Dudczig, C.G. Aneziris, M. Emmel, G. Schmidt, J. Hubalkova, H. Berek, "Characterization of carbon bonded alumina filters with active or reactive coatings in a steel casting simulator", Ceramics International, Vol. 40, 2014, pp. 16727-16742.
[20] R. Dekkers, Non-metallic inclusions in Steel, Ph.D. thesis, University of Leuven, 2002.
[21]      A. Kazakov, P. Kovalev, S. Ryaboshu, "Metallurgical expertise as the base for determination of nature of defects in metal products", CIS Iron and Steel Review, Vol. 1, No. 2, 2007, pp. 7-13. 
[22] P.K. Kovalev, "Improving production technology of tube Steel grades in converter process", Metalurgija, Vol. 55, No. 4, 2016, pp. 715-718.
[23] A. Baghaei, A.A. Nourbakhsh, R. Ebrahimi Kahrizsangi, V.R. Salvini, "Correlation of microstructure and mechanical properties of Al2O3-C bodies containing Nano-Al2O3 and Nano-TiO2 additives", International Journal of Applied Ceramic Technology, Vol. 17, No. 3, 2020, pp. 1505-1513.
[24]      K. Schwartzwalder, Method of making porous ceramic article, Patent US 3,090,094, 1963.
[25]      X. Wei, A. Yehorov, E. Storti, S. Dudczig, O. Fabrichnaya, C. G. Aneziris, O. Volkova, "Phenomenon of whiskers formation in Al2O3-C refractories" Advanced Engineering Materials, 2021, 2100718.
[26]      R. Khanna, M. Ikram-Ul Haq, Y. Wang, S. Seetharaman, V. Sahajwalla, "Chemical interactions of alumina-carbon refractories with molten steel at 1823 K (1550°C): implications for refractory degradation and steel quality", Metallurgical and Materials Transactions B, Vol. 42, 2011, pp. 677-684.
[27]      R. Khanna, S. Kongkarat, S. Seetharaman, V. Sahajealla, "Carbothermic reduction of Alumina at 1823 K in the presence of molten steel: a sessile drop investigation", ISIJ International, Vol. 52, 2012, pp. 992-999.
[28] E. Storti, R. Jankovský, D. Sedmidubský, S. Dudczig, CG. Aneziris, "Filter coatings based on combination of nanomaterials for Steel melt filtration", Advanced Engineering Materials, Vol. 22, 2020, pp. 1900457-64.
[29]      JH. Lee, MH. Kang, SK. Kim,YB. Kang, "Oxidation of Ti added ULC steel by CO gas simulating interfacial reaction between the steel and SEN during continuous casting" ISIJ International, Vol.58, 2018, pp. 1257-1266.
[30]      E. Steinmetz, "Shapes and formation of aluminum oxides in raw ingots and continuously cast slabs", Stahl u. Eisen, Vol.97, 1977, pp. 1154-1159.
[31]      E. Steinmetz, HU. Lindenberg, "Morphology of inclusions at aluminum deoxidation", Arch. Eissenhüttenwes, Vol. 47, 1976, pp. 199-204.
[32]      K. Okohira, N. Sato, H. Mori, "Observation of three-dimensional shapes of inclusions in low-Carbon Aluminum-killed Steel by scanning Electron microscope", Transactions of the Iron and Steel Institute of Japan, Vol. 14, 1974, pp. 103-109.