Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-29T07:55:40.472Z Has data issue: false hasContentIssue false

Effect of boron on the continuous cooling transformation kinetics in a low carbon advanced ultra-high strength steel (A-UHSS)

Published online by Cambridge University Press:  01 March 2013

G. Altamirano
Affiliation:
Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio “U”, Ciudad Universitaria, Morelia, Michoacán, México.
I. Mejía
Affiliation:
Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo. Edificio “U”, Ciudad Universitaria, Morelia, Michoacán, México.
A. Hernández-Expósito
Affiliation:
Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, ETSEIB – Universitat Politècnica de Catalunya. Av. Diagonal 647, Barcelona, Spain. Fundació CTM Centre Tecnològic, Av. de las Bases de Manresa, 1, Manresa, Spain.
J. M. Cabrera
Affiliation:
Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, ETSEIB – Universitat Politècnica de Catalunya. Av. Diagonal 647, Barcelona, Spain. Fundació CTM Centre Tecnològic, Av. de las Bases de Manresa, 1, Manresa, Spain.
Get access

Abstract

The aim of the present research work is to investigate the influence of B addition on the phase transformation kinetics under continuous cooling conditions. In order to perform this study, the behavior of two low carbon advanced ultra-high strength steels (A-UHSS) is analyzed during dilatometry tests over the cooling rate range of 0.1-200°C/s. The start and finish points of the austenite transformation are identified from the dilatation curves and then the continuous cooling transformation (CCT) diagrams are constructed. These diagrams are verified by microstructural characterization and Vickers micro-hardness. In general, results revealed that for slower cooling rates (0.1-0.5 °C/s) the present phases are mainly ferritic-pearlitic (F+P) structures. By contrast, a mixture of bainitic-martensitic structures predominates at higher cooling rates (50-200°C/s). On the other hand, CCT diagrams show that B addition delays the decomposition kinetics of austenite to ferrite, thereby promoting the formation of bainitic-martensitic structures. In the case of B microalloyed steel, the CCT curve is displaced to the right, increasing the hardenability. These results are associated with the ability of B atoms to segregate towards austenitic grain boundaries, which reduce the preferential sites for nucleation and development of F+P structures.

Keywords

Type
Articles
Copyright
Copyright © Materials Research Society 2013 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Committee on Automotive Applications, International Iron & Steel Institute, Advanced High Strength Steel Application Guidelines, pp. 113 (2009).Google Scholar
Zhao, J. C. and Notis, M. R., Mater. Sci. Eng. Rep. 15, 135207 (1995).CrossRefGoogle Scholar
Cota, A. B., Modenesi, P. J., Barbosa, R. and Santos, D. B., Scripta Mater. 40, 165169 (1999).CrossRefGoogle Scholar
You, W., Xu, W. H., Liu, Y. X., Bai, B. Z. and Fang, H. S., J. Iron Steel Res. Int. 14, 3942 (2007).CrossRefGoogle Scholar
Bhadeshia, H. K. D. H. and Honeycombe, R. W. K., Steels, Microstructures and Properties, third edition (Elsevier, Butterworth-Heinemann, 2006), pp. 7192.Google Scholar
Zhang, C., Cai, D., Wang, Y., Liu, M., Liao, B. and Fan, Y., Mater. Charact. 59, 16381642 (2008).CrossRefGoogle Scholar
Wang, X. M. and He, X. L., ISIJ Int. 42, 3846 (2002).CrossRefGoogle Scholar
Mejía, I., García de la Rosa, A., Bedolla-Jacuinde, A. and Cabrera, J. M., Mater. Res. Soc. Symp. Proc. 1373, 8994 (2012).CrossRefGoogle Scholar
Zhu, K., Oberbilling, C., Misik, C., Loison, D. and Iung, T., Mater. Sci. Eng. A528, 42224231 (2011).CrossRefGoogle Scholar
Lanier, L., Metauer, G. and Moukassi, M., Mikrochim. Acta 114115, 353361 (1994).CrossRefGoogle Scholar