Effect of microstructure on the impact toughness of high strength steels

Authors

  • Isabel Gutiérrez CEIT and TECNUN (University of Navarra)

DOI:

https://doi.org/10.3989/revmetalm.029

Keywords:

Charpy model, Mechanical properties, Microalloying, Microstructure, Toughness

Abstract


One of the major challenges in the development of new steel grades is to get increasingly high strength combined with a low ductile brittle transition temperature and a high upper shelf energy. This requires the appropriate microstructural design. Toughness in steels is controlled by different microstructural constituents. Some of them, like inclusions, are intrinsic while others happening at different microstructural scales relate to processing conditions. A series of empirical equations express the transition temperature as a sum of contributions from substitutional solutes, free nitrogen, carbides, pearlite, grain size and eventually precipitation strengthening. Aimed at developing a methodology that could be applied to high strength steels, microstructures with a selected degree of complexity were produced at laboratory in a Nb-microalloyed steel. As a result a model has been developed that consistently predicts the Charpy curves for ferrite-pearlite, bainitic and quenched and tempered microstructures using as input data microstructural parameters. This model becomes a good tool for microstructural design.

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References

Altuna, M.A., Gutiérrez, E.I. (2005). Relación microestructuracomportamiento mecánico en estructuras bainíticas. Rev. Metal. 41 (5), 357–364. http://dx.doi.org/10.3989/revmetalm.2005.v41.i5.225

Altuna, M.A., Iza-Mendia, A., Gutiérrez, I. (2012). Precipitation of Nb in ferrite after austenite conditioning. Part II: Strengthening Contribution in High-Strength Low-Alloy (HSLA) Steels. Metall. Mater. Trans. A 43 (12), 4571–4586. http://dx.doi.org/10.1007/s11661-012-1270-x

Bengochea, R., López, B., Gutiérrez, I. (1998). Microstructural evolution during the austenite to ferrite transformation from deformed austenite. Metall. Mater. Trans. A 29 (2), 417–426. http://dx.doi.org/10.1007/s11661-998-0122-1

Bhadeshia, H.K.D.H. (2001). Bainite in Steels. Second Edition, IOM Communications Ltd, London.

Bhattacharjee, D., Knott, J.F., Davis, C.L. (2004). Charpy-Impact-Toughness prediction using an "effective" grain size for thermomechanically controlled rolled microalloyed steels. Metall. Mater. Trans. A 35 (1), 121–130. http://dx.doi.org/10.1007/s11661-004-0115-7

Díaz-Fuentes, M., Iza-Mendia, A., Gutiérrez, I. (2003). Analysis of different acicular ferrite microstructures in low carbon steels by EBSD. Study of their toughness behavior. Metall. Mater. Trans. A 34 (11), 2505–2516. http://dx.doi.org/10.1007/s11661-003-0010-7

Gladman, T., Holnes B, McIvor, I.D. (1971). Effect of secondphase particles on strength, toughness and ductility. Proc. Conf. Effect of second-phase particles on the mechanical properties of steel, Corporate Laboratories of the British Steel Corporation and the Iron and Steel Institute, Scarborough, London, pp. 67–78.

Gladman, T. (1997). The Physical Metallurgy of Microalloyed Steels. Institute of Materials, London, England, p. 55.

Gladman, T. (1999). Precipitation hardening in metals. Mater. Sci. Technol. 15 (1), 30–36. http://dx.doi.org/10.1179/026708399773002782

Gourgues, A.F., Flower, H.M., Lindley, T.C. (2000). Electron backscattering diffraction study of acicular ferrite, bainite, and martensite steel microstructures. Mater. Sci. Technol. 16 (1), 26–40. http://dx.doi.org/10.1179/026708300773002636

Gutiérrez, I. (2013). Effect of microstructure on the impact toughness of Nb-microalloyed steel: Generalisation of existing relations from ferrite–pearlite to high strength microstructures. Mat. Sci. Eng. A 571, 57–67. http://dx.doi.org/10.1016/j.msea.2013.02.006

Gutiérrez, I., Altuna, A. (2008). Work-hardening of ferrite and microstructure-based modelling of its mechanical behaviour under tension. Acta Mater. 56 (17), 4682–4690. http://dx.doi.org/10.1016/j.actamat.2008.05.023

Herman, J.C., Donnay, B., Leroy, V. (1992). Precipitation Kinetics of Microalloying Additions during Hot-rolling of HSLA Steels. ISIJ Int. 32 (6), 779–785. http://dx.doi.org/10.2355/isijinternational.32.779

Irvine, K.J., Pickering, F.B., Gladman, T. (1967). Grain-Refined C-Mn Steels. JISI, 205, 161–182.

Iza-Mendia, A., Altuna, M.A. Pereda B., Gutiérrez, I. (2012). Precipitation of Nb in Ferrite After Austenite Conditioning. Part I: Microstructural Characterization. Metall. Mat. Trans. A 43 (12), 4553–4570. http://dx.doi.org/10.1007/s11661-012-1395-y

Iza-Mendia, A., Gutiérrez I. (2013). Generalization of the existing relations between microstructure and yield stress from ferrite–pearlite to high strength steels. Mat. Sci. Eng. A 561 (20), 40–51. http://dx.doi.org/10.1016/j.msea.2012.10.012

Kestenbach, H.J. (1997). Dispersion hardening by niobium carbonitride precipitation in ferrite. Mater. Sci. Technol. 13 (9), 731–739. http://dx.doi.org/10.1179/mst.1997.13.9.731

López, B. (2006). Characterisation and Modelling of Strain Induced Precipitation, ECSC Final Report: Contract No 7210-PR/350. CAMSIP, by Scott, C., Rose, A., Soenen, B., Lopez, B., Paul, G., Published Technical Steel Research, EUR 22431, ISBN 92-79-03740-4.

Malik, L., Lund, J.A. (1972). A Study of Strengthening Mechanisms in Tempered Martensite From a Medium Carbon Steel. Metall. Trans. 3 (6), 1403–1406. http://dx.doi.org/10.1007/BF02643024

Mintz, B., Morrison, W.B., Jones, A. (1979). Influence of carbide thickness on impact transition temperature of ferritic steels. Mater. Sci. Technol. 6 (1), 252–260.

Mintz, B., Peterson, G., Nassar A. (1994). Structure-Property Relationships in Ferrite-Pearlite Steels. Ironmak. Steelmak. 21 (3), 215–222.

Novillo, E., Cotrina, E., Iza-Mendia, A., López, B, Gutiérrez, I. (2005). Factors limiting the achievable ferrite grain refinement in hot worked microalloyed steels materials. Science Forum 500–501, 355–362. http://dx.doi.org/10.4028/www.scientific.net/MSF.500-501.355

Pickering, F.B. (1978). Physical metallurgy and the design of steels. Ed. Applied Science Publishers, p. 10.

Pickering, F.B. (1993). Structure-property relationships in steels. Materials Science and Engineering, Ed. R.W. Cahn, P. Haasen, E.J. Kramer, Vol. 7, Constitution and Properties of Steels, Ed. F.B. Pickering, VCH, p. 47.

Sung, H.K., Shin, S.Y., Hwang, B., Lee, C.G., Lee, S. (2011). Effects of Rolling and Cooling Conditions on Microstructure and Tensile and Charpy Impact Properties of Ultra-Low-Carbon High-Strength Bainitic Steels. Metall. Mat. Trans. A 42 (7), 1827–1835. http://dx.doi.org/10.1007/s11661-010-0590-y

Todinov, M.T. (2001). An efficient method for estimating from sparse data the parameters of the impact energy variation in the ductile-brittle transition region. Int. J. Fracture 111 (2), 131–150. http://dx.doi.org/10.1023/A:1012212610024

Zajac, S., Achwinn, V., Tacke, K.H. (2005). Characterisation and quantification of complex bainitic microstructures in high and ultra-high strength linepipe steels. Materials Science Forum 500–501, 387–394. http://dx.doi.org/10.4028/www.scientific.net/MSF.500-501.387

Zubialde, R., Uranga, P., López, B., Rodriguez-Ibabe, J.M. (2013). Heterogeneity and microstructural features intervening in the ductile-brittle transition of ferrite-pearlite steels, Conf. Proc. Materials Science and Technology (MS&T), Montreal, Quebec, Canada, pp. 313–320.

Published

2014-12-30

How to Cite

Gutiérrez, I. (2014). Effect of microstructure on the impact toughness of high strength steels. Revista De Metalurgia, 50(4), e029. https://doi.org/10.3989/revmetalm.029

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