Abstract
The toughness of the base material (BM) and the coarse-grain heat-affected zone (CGHAZ) of N-controlled fire- and seismic-resistant (FSR) steels (FSR1: 0.03Ti, 0.25Mo, 0.018Nb; FSR2: 0.07Ti, 0.09Mo; and FSR3: 0.14Ti, 0.17Mo) were systematically investigated. FSR1 steel exhibited better toughness than FSR2 and FSR3 steels in the BM and CGHAZ. Fractographic analysis of the BM and CGHAZ revealed the presence of coarse TiN precipitates in fracture initiation sites, which are responsible for the low toughness of FSR2 and FSR3 steels. Coarse TiN precipitates with equivalent diameters of 1 to 6 μm are present in all FSR steels. However, FSR1 steel has relatively lower number density and area fraction of TiN precipitates. The formation mechanism of TiN precipitates is elucidated from the theoretical thermodynamic approach and validated with a quantitative metallographic observation; it was found that the mechanism is the same for both the BM and CGHAZ in all FSR steels. The equilibrium solubility temperature of TiN precipitates in FSR1 steel was lower than the solidus temperature, which resulted in fewer coarse TiN precipitates. The lower boundary of both the Ti/N (hypostoichiometric) ratio and TiN solubility product at the solidus temperature is highly recommended for increased toughness of FSR steels containing Ti, Mo, and Nb.
Similar content being viewed by others
Notes
JEOL is a trademark of Japan Electron Optics Ltd., Tokyo.
References
W. Sha, F.S. Kelly, and Z.X. Guo: J. Mater. Eng. Perform., 1999, vol. 8, pp. 606–12.
F.S. Kelly and W. Sha: J. Constr. Steel Res., 1999, vol. 50, pp. 223–33.
Y. Mizutani, K. Ishibashi, K. Yoshii, Y. Watanabe, R. Chijhwa, and Y. Yoshida: 590 MPa Class of Fire-Resistant Steel for Building Structural Use, July 2004.
H. Tamehiro, R. Chijiiwa, K. Funato, Y. Yoshida, Y. Horii, and R. Uemori: Development and Practical Applications of Fire-Resistant Steel for Buildings, 1993, vol. 58.
B.K. Panigrahi: Bull. Mater. Sci., 2006, vol. 29, pp. 59–66.
T. Suzuki, Y. Yoshida, Y. Shimura, Y. Suzuki, S. Kubota, and M. Nagata: Development of Building Structural Steel with High Yield Ratio and High Yield Point Leading to Innovative Steel Structural System, 2008.
R. Wan, F. Sun, L. Zhang, and A. Shan: Mater. Des., 2012, vol. 35, pp. 335–41.
Q.L. Young: The Second Phase of the Steel Materials, Metallurgical Industry Press, Beijing, 2006.
R. Wan, F. Sun, L. Zhang, and A. Shan: Mater. Des., 2012, vol. 36, pp. 227–32.
R. Wan, F. Sun, L. Zhang, and A. Shan: J. Mater. Eng. Perform., 2014, vol. 23, pp. 2780–86.
S.-H. Jeong, J.-H. Eom, H.-G. Choi, B.-H. Jeong, S.-H. Hur, and C.-Y. Kang: J. Weld. Join., 2014, vol. 32, pp. 29–34.
J. Moon and C. Lee: J. Kor. Weld. Join. Soc., 2013, vol. 31, pp. 44–49.
Y. Kang, G. Park, S. Jeong, and C. Lee: Metall. Mater. Trans. A, 2018, vol. 49A, pp. 177–86.
J. Moon, C. Lee, S. Uhm, and J. Lee: Acta Mater., 2006, vol. 54, pp. 1053–61.
P. Gong, E.J. Palmiere, and W.M. Rainforth: Acta Mater., 2015, vol. 97, pp. 392–403.
W. Yan, Y.Y. Shan, and K. Yang: Metall. Mater. Trans. A, 2007, vol. 38A, pp. 1211–22.
S.J. Spachinger, W. Ernst, and N. Enzinger: Weld. World, 2017, vol. 61, pp. 1117–31.
D.P. Fairchild, D.G. Howden, and W.A.T. Clark: Metall. Mater. Trans. A, 2000, vol. 31A, pp. 653–67.
L.P. Zhang, C.L. Davis, and M. Strangwood: Metall. Mater. Trans. A, 1999, vol. 30A, pp. 2089–96.
W. Yan, Y.Y. Shan, and K. Yang: Metall. Mater. Trans. A, 2006, vol. 37A, pp. 2147–58.
K. Inoue, I. Ohnuma, H. Ohtani, K. Ishida, and T. Nishizawa: ISIJ Int., 1998, vol. 38, pp. 991–97.
Y. Shen and S.S. Hansen: Metall. Mater. Trans. A, 1997, vol. 28A, pp. 2027–35.
J.H. Jang, Y.-U. Heo, C.-H. Lee, H.K.D.H. Bhadeshia, and D.-W. Suh: Mater. Sci. Technol., 2013, vol. 29, pp. 309–13.
S. Kou: Welding Metallurgy, 2nd ed., vol. 822. Wiley, Hoboken, NJ (2003).
Standard Test Methods for Notched Bar Impact Testing of Metallic Materials, ASTM E23-07a, ASTM, West Conshohocken, PA, 2007, vol. 14.
E. Keehan, L. Karlsson, H.K.D.H. Bhadeshia, and M. Thuvander: Mater. Sci. Technol., 2008, vol. 24, pp. 1183–88.
H.K.D.H. Bhadeshia: Bainite in Steels, 2nd ed., IOM Communications Ltd., London, 2001, vol. 21A.
S.G. Lee, D.H. Lee, S.S. Sohn, W.G. Kim, K.K. Um, K.S. Kim, and S. Lee: Mater. Sci. Eng. A, 2017, vol. 697, pp. 55–65.
Standard Test Methods for Determining Average Grain Size, ASTM E112, ASTM, West Conshohocken, PA, 1996.
R.G. Miller: Beyond ANOVA, Basics of Applied Statistics, 1st ed., Wiley-Interscience, Hoboken, NJ, 1997.
S. Dumitrescu and M. Hillert: ISIJ Int., 1999, vol. 39, pp. 84–90.
E.J. Pavlina, J.G. Speer, and C.J. Van Tyne: Scripta Mater., 2012, vol. 66, pp. 243–46.
H. Li, Y.L. Feng, D. Zhang, M. Song, and D.Q. Cang: Rare Met., 2013, vol. 32, pp. 318–22.
E.J. Pavlina, J.G. Speer, and C.J. Van Tyne: Scripta Mater., 2012, vol. 66, pp. 243–46.
Z.X. Zhu, L. Kuzmikova, M. Marimuthu, H.J. Li, and F. Barbaro: Sci. Technol. Weld. Join., 2013, vol. 18, pp. 1–10.
L.P. Zhang, C.L. Davis, and M. Strangwood: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 1147–55.
M.J. Balart, C.L. Davis, and M. Strangwood: Scripta Mater., 2004, vol. 50, pp. 371–75.
H. Somekawa and T. Mukai: Mater. Trans., 2006, vol. 47, pp. 995–98.
O. Yoo, Y.-J. Oh, B.-S. Lee, and S.W. Nam: Mater. Sci. Eng. A, 2005, vol. 405, pp. 147–57.
L. Aucott, S.W. Wen, and H. Dong: Mater. Sci. Eng. A, 2015, vol. 622, pp. 194–203.
Acknowledgments
The financial support for this work was provided by the Ministry of Trade, Industry and Energy (MOTIE, Korea) under the industry technology innovation program (Grant No. 10063448). The authors are grateful to Professor Hyun-Uk Hong and his graduate student Mr. Jun Yeon Kim, Changwon National University, for providing the opportunity to electropolish TEM samples. A special thanks to the reviewers for their kind efforts in giving valuable comments.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Manuscript submitted January 22, 2019.
Rights and permissions
About this article
Cite this article
Ramachandran, D.C., Murugan, S.P., Moon, J. et al. The Effect of the Hyperstoichiometric Ti/N Ratio Due to Excessive Ti on the Toughness of N-Controlled Novel Fire- and Seismic-Resistant Steels. Metall Mater Trans A 50, 3514–3527 (2019). https://doi.org/10.1007/s11661-019-05266-1
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11661-019-05266-1