Abstract
Through the thermo-mechanical control process (TMCP), a high Nb low Mo fire resistant steel with the yield strength (YS) of 521 MPa at room temperature (RT) and 360 MPa at elevated temperature (ET) of 600 °C was developed based on MX (M=Nb, V, Mo; X=C, N) precipitation strengthening. A series of tensile and constant load tests were conducted to study the mechanical properties at ET. The dynamic continuous cooling transformation (CCT) as well as precipitation behavior of microalloy carbonitride was investigated by means of thermal simulator and electron microscopy approaches. Results showed that the failure temperature of tested steel was determined as 653 °C, and the granular bainite was obtained when the cooling rate was higher than 10 °C/s. In the rolled state, a certain amount of M/A islands was observed. During heating from RT to ET, M/A islands disappeared, and cementites and high dense compound precipitates (Nb, Mo, V)C with size of less than 10 nm precipitated in ferrite at ET (600 °C), which resulted in precipitation strengthening at ET.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Q. B. Yu, X. H. Liu, X. P. Zhao, Microstructural Morphology and Analysis of TMCP Steels, Science Press, Bei**g, 2010.
R. C. Wan, Study on Strengthening Mechanism of Mo and Replacement of Mo in Fire-resistant Steel, Shanghai Jiao Tong University, Shanghai, 2012.
M. A. Dezfuly, B. A. Hugaas, A. Brownrigg, Mater. Sci. Technol. 6 (1990) 1210–1214.
R. Chijiiwa, H. Tamehiro, A. Yoshie, K. Funato, Y. Yoshida, Y. Horii, R. Uemori, in: G. Liu, H. Stuart, H. Zhang, C. Li, (Eds), HSLA Steels 95 Conference Proceed, China Science and Technology Press, Bei**g, 1995, pp. 584–589.
E. G. Dere, H. Sharma, R. H. Petrov, J. Sietsma, S. E. Offerman, Scripta Mater. 68 (2013) 651–654.
R. Chijiiwa, H. Tamehiro, Y. Yoshida, K. Funato, R. Uemori, Y. Horii, Nippon Steel Tech. Rep. 6 (1993) No. 58, 47–55.
C. F. Yang, Y. Q. Zhang, Steel Construction 12 (1997) No. 38, 29–34.
M. S. Walp, J. G. Speer, K. M. David, Adv. Mater. Processes 10 (2004) 34–36.
K. P. Bimal, Bull. Mater. Sci. 29 (2006) 59–66.
R. C. Wan, F. Sun, L. T. Zhang, A. D. Shan, Mater. Des. 36 (2012) 227–232.
X. Q. Pan, Effect of Mo and V on the Microstructure and Properties of Fire-resistant Steel, Chongqing University, Chongqing, 2007.
G. S. John, G. J. Steven, C. C. Justin, S. W. Matthew, K. M. David, in: Proceedings of the Joint International Conference of HSLA Steels 2005 and ISIJGS 2005, 2005, pp. 818–823.
R. C. Wan, F. Sun, L. T. Zhang, A. D. Shan, Mater. Des. 35 (2012) 335–341.
G. W. Yang, X. J. Sun, Z. D. Li, X. X. Li, Q. L. Yong, Mater. Sci. Technol. 21 (2013) 118–124.
W. N. Lee, S. G. Hong, C. G. Park, S. H. Park, Metall. Mater. Trans. A 33 (2001) 1689–1691.
R. Uemori, R. Chijiiwa, H. Tamehiro, H. Morikawa, Appl. Surf. Sci. 76/77 (1994) 255–260.
Q. L. Yong, Secondary Phase in Steels, Metallurgical Industry Press, Bei**g, 2006.
C. Y. Chen, C. C. Chen, J. R. Yang, Mater. Charact. 88 (2014) 69–79.
J. H. Jang, Y. U. Heo, C. H. Lee, H. K. D. H. Bhadeshia, D. W. Suh, Mater. Sci. Technol. 29 (2013) 309–313.
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation Item: Item Sponsored by National Basic Research Program of China (2010CB630805)
Rights and permissions
About this article
Cite this article
Zhang, Zy., Yong, Ql., Sun, Xj. et al. Microstructure and mechanical properties of precipitation strengthened fire resistant steel containing high Nb and low Mo. J. Iron Steel Res. Int. 22, 337–343 (2015). https://doi.org/10.1016/S1006-706X(15)30009-1
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1016/S1006-706X(15)30009-1