Browse > Article
http://dx.doi.org/10.3365/KJMM.2012.50.7.487

Effects of Coiling Temperature and Carbides Behavior on Stretch-flangeability for 980MPa Hot-rolled Steels  

Chun, Eun-Joon (Department of Materials Science and Engineering, Pusan National University)
Lee, Ju-Seung (Department of Materials Science and Engineering, Pusan National University)
Do, Hyeonghyeop (Technical Research Center, Hyundai Steel Company)
Kim, Seong-Ju (Technical Research Center, Hyundai Steel Company)
Choi, Yoon-Suk (Materials and Processing Division, UES, Inc.)
Park, Yong-Ho (Department of Materials Science and Engineering, Pusan National University)
Kang, Namhyun (Department of Materials Science and Engineering, Pusan National University)
Publication Information
Korean Journal of Metals and Materials / v.50, no.7, 2012 , pp. 487-493 More about this Journal
Abstract
To analyze the factors on stretch-flangeability for 980 MPa-grade hot-rolled steels, two types of steels (Fe-Cr and Fe-Mo) were manufactured by hot-rolling. Manufactured steels at the low coiling temperature, such as 400 and $500^{\circ}C$, had poor stretch-flangeability due to un-uniformly distributed carbides and a large deviation of interphase hardness. However, when the coiling temperature was set at $650^{\circ}C$ with Fe-Cr steel, 998 MPa of ultimate tensile strength, 19% of total elongation and 65% of the hole expanding ratio were achieved by microstructural constituents of polygonal ferrite (PF) and granular ferrite (GF) dispersed with fine carbides (<50 nm). Therefore, the material to attain 980 MPa with superior formability was the Fe-Cr steel that was precipitation-hardened in polygonal ferrite and granular ferrite at the coiling temperature $650^{\circ}C$.
Keywords
metals; rolling; precipitation; hardness test; stretch-flangeability;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 S. Kazuhiro, F. Yoshimasa, and K. Shinjiro, JFE Technical Report. 10, 19 (2007).
2 M. Miura, M. Nakaya, and Y. Mukai, Kobelco Technology Review. 28, 8 (2008).
3 M. Saiji, H. Kohei, and T. Yasushi, JFE Technical Report. 10, 13 ( 2007).
4 M. Takahashi, O. Kawano, T. Hayashida, R. Okamoto, and H. Taniguchi, Nippon Steel Technical Report. 88, 8 (2003).
5 X. Fang, Z. Fan, and B. Ralph, J. Mater. Sci. 38, 3877 (2003).   DOI   ScienceOn
6 Y. R. Cho, Ph. D. Thesis, pp. 4-34, Pusan National University, Busan (1999).
7 Y. R. Cho, J. H. Chung, H. H. Ku, and I. B. Kim, Met. Mater. Int. 5, 571 (1999).   DOI
8 Y. R. Cho, J. H. Chung, H. K. S. Seol, and I. B. Kim, J. Kor. Inst. Met. Mater. 37, 1494 (1999).
9 E. J. Chun, J. S. Lee, H. H. Do, S. J. Kim, Y. H. Park, and N. Kang, Kor. J. Mater. Res. 22, 42 (2012).   DOI   ScienceOn
10 S. Chatterjee and H. K. D. H. Bhadeshia, Mater. Sci. Tech. 23, 606 (2007).   DOI   ScienceOn
11 K. Hasegawa, K. Kawamura, T. Urabe, and Y. Hosoya, ISIJ, Int. 44, 603 (2004).   DOI   ScienceOn
12 M. H. Cai, H. Ding, Y. K. Lee, Z. Y. Tang, and J. S. Zhang, ISIJ Int. 51, 476 (2011).   DOI   ScienceOn
13 A. Barbacki, J. Mater. Process. Technol. 53, 57 (1995).   DOI   ScienceOn
14 R. J. Comstock, D. K. Scherrer, and R. D. Adamczyk, J. Mater. Eng. Perform.15, 675 (2006).   DOI   ScienceOn
15 V. Uthaisangsuk, U. Prahl, and W. Bleck, Comput. Mater. Sci. 45, 617 (2009).   DOI   ScienceOn
16 G. Krauss and S.W. Thompson, ISIJ Int. 35, 937 (1995).   DOI   ScienceOn
17 J. B. Lee, N. Kang, J. T. Park, S. T. Ahn, Y. D. Park, I. D. Choi, K. R. Kim, and K. M. Cho, Mater. Chem. Phys. 129, 365 (2011).   DOI   ScienceOn
18 J. B. Lee, N. Kang, J. T. Park, S. T. Ahn, Y. D. Park, I. D. Choi, D. G. Nam, and K. M. Cho, Korean J. Met. Mater. 48, 974 (2010).   DOI   ScienceOn
19 N. Kang, Y. H. Park, Y. D. Kim, E. J. Chun, S. J. Kim, H. H. Do, and Y. D. Park, Materials Science& Technology 2011 Conference and Exhibition(eds. S. K. Will, A. B. Pandey), p. 103, The Minerals, Metals & Materials Society, Columbus, Ohio USA (2011).
20 R. Narayanasamy, C. S. Narayanan, P. Padmanabhan, and T. Venugopalan, Int. J. Adv. Manuf. Tech. 47 365 (2010).   DOI   ScienceOn