Browse > Article
http://dx.doi.org/10.3740/MRSK.2014.24.8.401

Effect of R Phase Formation on the Mechanical Properties of 25Cr-7Ni-2Mo-4W Super Duplex Stainless Steel  

Lee, Byung-Chan (Korea Polytechnic VII College)
Kang, Chang-Yong (Department of Metallurgical Engineering, Pukyong National University)
Publication Information
Korean Journal of Materials Research / v.24, no.8, 2014 , pp. 401-406 More about this Journal
Abstract
In this study, we investigated the precipitation behavior of the R-phase precipitated at the initial stage of aging and its effects on the mechanical properties of 25%Cr-7%Ni-2%Mo-4%W super duplex stainless steel. The R-phase was mainly precipitated at the interface of ferrite/austenite phases and inside of the ferrite phase during the initial stage of aging. It was transformed into the ${\sigma}$-phase with an increase of the aging time. The ferrite phase was decomposed into a new austenite(${\gamma}_2$)phase and the ${\sigma}$-phase by an aging treatment. The R phase was an intermetallic compound showing higher molybdenum and tungsten concentrations than the matrix and also showed higher molybdenum and tungsten concentrations than the ${\sigma}$ phase. In the initial stage of aging, precipitation of the R-phase did not change the hardness, the strength and the elongation. The hardness and the strength increased upon a longer aging time, but the elongation rapidly decreased. These results show that the R-phase did not significantly affect the hardness and the strength, though it did influence the elongation.
Keywords
super duplex stainless steel; hardness; tensile properties; R-phase; ${\sigma}$ phase;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 F. B. Pickering, Int. Met. Rev., December, 227 (1976).
2 C. F. G. Baxter and G. R. Warburton, Proc. Int. Conf. Duplex '94, p.18, Glasgow, Scotland, 13-16, November (1994).
3 J. Charles, Proc. Int. Conf. Duplex '94. Paper KI, Glasgow. Scotland (1994).
4 S. C. Kim, Z. Zang, Y. Furuya, C. Y. Kang, J. H. Sung, Q. Q. Ni, Y. Watanabe and I. S. Kim, Mat. Trans, 46(7), 1056 (2005).
5 J. M. Nicholls, Int. Conf. Duplex '94, Paper. KIII, Glasgow, Scotland, 13-16 November (1994).
6 T. Huhala, J. U. Nilson, A. Wilson and P. Jonson, Int. Conf. Duplex '94, p.43, Glasgow, Scotland, 13-16 November (1994).
7 T. H. Hwang, J. H. Kim, K. H. Kim, W. J. Moon and C. Y. Kang, Met. Mater. Int., 20(1). 13 (2014).   DOI   ScienceOn
8 J. Cui, I. S. Park, C. Y. Kang and K. Miyahara, ISIJ Int., 41(2), 192 (2001).   DOI   ScienceOn
9 K. Kondo, M. Ueda, K. Ogawa, and M. Igarashi, Proc. Conf. Innovation of Stainless Steel, p.191, Florence, Italy 11-14 October (1993).
10 C. Y. Kang, J. H. Kim, Kor. J. Met. Mater. Int., 49(3), 197 (2011).   DOI   ScienceOn