Skip to main content

Pearlite Refining Strategies for Hypoeutectic Gray Cast Iron

Abstract

Pearlite refining is one of the most used methods to increase the strength of cast irons, and it can be achieved using different strategies. In this work, three strategies to obtain pearlite refining were applied to a given hypoeutectic gray cast iron centrifuged in a coated steel mold: (1) increasing the Cu, Mo and Cr contents; (2) intensifying the cooling rate of the metallic mold; and (3) cooling of the cast iron with forced air. Strategies 2 and 3 aimed to increase the cooling rate during the eutectoid reaction. Then, four experiments were conducted: a reference experiment and other three applying separately the strategies above. Materials samples were characterized by optical metallography, chemical analyses, microhardness, pearlite interlamellar spacing measurements and tensile tests. The metallographic examination did not show any important change in the graphite morphology. The pearlite interlamellar spacing and microhardness were computed as distribution curves from at least thirty measurements in the materials matrices. These curves showed a decrease in pearlite interlamellar spacing and an increase in pearlite microhardness for the three materials in which the pearlite refining strategies were applied as compared to the reference material. The mean pearlite interlamellar spacings were reduced from 0.10 μm for the reference material to 0.07 μm, 0.08 μm and 0.08 μm for the materials in which strategies 1, 2 and 3 were applied, respectively. The UTS increased from 378 MPa for the reference material to 423 MPa, 418 MPa and 390 MPa for the strategies 1, 2 and 3, respectively.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5

References

  1. T. Sjögren, H. Svensson, Study of the eutectoid transformation in grey cast irons and its effect on mechanical properties. Key Eng. Mater. 457, 157–162 (2010)

    Article  Google Scholar 

  2. W. Xu, M. Ferry, Y. Wang, Influence of alloying elements on as-cast microstructure and strength of gray iron. Mater. Sci. Eng. A 390(1–2), 326–333 (2005)

    Article  Google Scholar 

  3. G. Krauss, Principles of Heat Treatment of Steel (American Society of Metals, Ohio, 1980)

    Google Scholar 

  4. F.G. Caballero, C. Capdevila, Modeling of the interlamellar spacing. Acta Metall. 42, 537–542 (2000)

    CAS  Google Scholar 

  5. G.F. Vander Voort, A. Roósz, Measurement of the interlamellar spacing of pearlite. Metallography 17, 1–17 (1984)

    CAS  Article  Google Scholar 

  6. V. Fourlakidis, A. Diószegi, A generic model to predict the ultimate tensile strength in pearlitic lamellar graphite iron. Mater. Sci. Eng. A 618, 161–167 (2014)

    CAS  Article  Google Scholar 

  7. A. Freulon, J. Sertucha, J. Lacaze, Solidification and room temperature microstructure of a fully pearlitic compacted graphite cast iron. Trans. Indian Inst. Met. 71(11), 2651–2656 (2018)

    CAS  Article  Google Scholar 

  8. G. Zhang, M. Enomoto, Interlamellar spacing of pearlite in a near-eutectoid Fe–C alloy. ISIJ Int. 49(6), 921–927 (2009)

    CAS  Article  Google Scholar 

  9. F.P. Incropera, D.P. DeWitt, T.L. Bergman, A.S. Lavine, Fundamentals of Heat and Mass Transfer, 6th edn. (Wiley, Hoboken, 2006)

    Google Scholar 

  10. S. Vacca, M.A. Martorano, R. Heringer, M. Boccalini, Determination of the heat transfer coefficient at the metal-mold interface during centrifugal casting. Metall. Mater. Trans. A 46(5), 2238–2248 (2015)

    CAS  Article  Google Scholar 

  11. ASM Handbook, Volume 9—Metallography and Microstructure, Quantitative Metallography Section, 8th edn. (American Society for Metals & ASM International, 1998)

  12. D.M. Stefanescu, G. Alonso, P. Larrañaga, R. Suarez, On the stable eutectic solidification of iron–carbon–silicon alloys. Acta Mater. 103, 103–114 (2016)

    CAS  Article  Google Scholar 

  13. G. Alonso, P. Larranaga, J. Sertucha, R. Suarez, D.M. Stefanescu, Gray cast iron with high austenite-to-eutectic ratio part I—calculation and experimental evaluation of the fraction of primary austenite in cast iron. Trans. Am. Foundry Soc. 120(12–033), 329–336 (2012)

    CAS  Google Scholar 

  14. J. Lacaze, J. Sertucha, Effect of tin on the phase transformations of cast irons. J. Phase Equilib. Diffus. 38(5), 743–749 (2017)

    CAS  Article  Google Scholar 

  15. R.B. Gundlach, W.G. Scholz, Phosphide eutectic in gray cast irons containing molybdenum and/or chromium. AFS Trans. 81, 395–402 (1973)

    CAS  Google Scholar 

Download references

Acknowledgements

The authors are thankful for the financial support from Empresa Brasileira de Pesquisa e Inovação Industrial (EMBRAPII), Mahle Metal Leve S.A and Fundação de Apoio ao Instituto de Pesquisas Tecnológicas (FIPT).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to M. L. Lima.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This paper is an invited submission to IJMC selected from presentations at the 2nd Carl Loper 2019 Cast Iron Symposium held September 30 to October 1, 2019, in Bilbao, Spain.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lima, M.L., Albertin, E., Correa, E.R. et al. Pearlite Refining Strategies for Hypoeutectic Gray Cast Iron. Inter Metalcast 14, 766–773 (2020). https://doi.org/10.1007/s40962-020-00413-6

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40962-020-00413-6

Keywords

  • pearlite
  • refining
  • gray cast iron
  • pearlite interlamellar spacing
  • microhardness