• PDF / 643,506 Bytes
• 3 Pages / 612 x 792 pts (letter) Page_size
• 103 Downloads / 255 Views

DOWNLOAD

REPORT

---

The National Natural Science Foundation of China and the Korea Science and Engineering Foundation are acknowledged for their financial support. REFERENCES 1. H.A. Lipsitt, D. Shechtman, and R.E. Schafrik: Metall. Trans. A, 1980, vol. 11A, pp. 1369-75. 2. Y.W. Kim: J. Met., 1989, vol. 41, pp. 24-30. 3. T. Shimizu, T. Iikubo, and S. Isobo: Mater. Sci. Eng. A, 1992, vol. A153, pp. 602-07. 4. D.W. Mckee and K.L. Luthra: Surface Coating Technol., 1993, vol. 56, pp. 109-17. 5. H. Mabuchi, T. Asai, and Y. Nakayama: Scripta Metall., 1989, vol. 23, pp. 685-89. 6. J.L. Smialek and P.K. Brindley: Scripta Metall., 1990, vol. 24, pp. 1291-96. 7. R.P. Skowronski: J. Am. Ceram. Soc., 1994, vol. 77, pp. 1098-100. 8. T.C. Munro and B. Gleeson: Metall. Mater. Trans. A, 1996, vol. 27A, pp. 3761-72. 9. S. Taniguchi, T. Shibata, and A. Murakami: Oxid. Met., 1994, vol. 41, pp. 103-13. 10. J.L. Klansky, J.P. Nic, and D.E. Mikkola: J. Mater. Res., 1994, vol. 9, pp. 255-58. 11. F.J.J. van Loo and G.D. Rieck: Acta Metall., 1973, vol. 21, pp. 61-71. 12. F.J.J. van Loo and G.D. Rieck: Acta Metall., 1973, vol. 21, pp. 73-84. 13. D.W. Mckee and S.C. Huang: Corr. Sci., 1992, vol. 33, pp. 1899-914. 14. K.L. Luthra: Oxid. Met., 1991, vol. 36, pp. 475-90. 15. G. Wang, B. Gleeson, and D.L. Douglass: Oxid. Met., 1989, vol. 31, pp. 415-29.

Superplastic Forming of Duplex Stainless Steel S.N. PATANKAR, C.T. LIM, and M.J. TAN Duplex stainless steels are a class of dual-phase materials with a ferritic-austenitic microstructure.[1] Duplex stainless

S.N. PATANKAR, Research Fellow, C.T. LIM, Graduate Student, and M.J. TAN, Associate Professor, are with the School of Mechanical and Production Engineering, Nanyang Technological University, Singapore 639798. Manuscript submitted September 23, 1999. 2394—VOLUME 31A, SEPTEMBER 2000

steels provide combinations of properties exceeding singlephase ferritic or austenitic stainless steels and are popular because of their high strength and superior corrosion resistance. The fine-grained structure in duplex stainless steels is one of the contributing factors that makes them stronger than most austenitic stainless steels and excellent superplastic materials. Superplasticity in duplex stainless steels was reported as early as 1967 and yet there has been no attempt to superplastically form these materials.[2,3,4] As in any other dual-phase superplastic material, superplasticity in duplex stainless steel is by the virtue of severe deformation of the softer phase and its recrystallization upon reaching a critical strain in the vicinity of harder phase. The objective of this article is to report some of the observations made pertaining to superplastic forming of duplex stainless steel. Duplex stainless steel 2205 sheets of 2-mm thickness, supplied by Inco Alloys, (Huntington, WV) were used in this study. Chemical composition of the duplex stainless steel is given in Table I. Superplastic forming was carried out on a Murdock (Compton, CA) 140-10001 SPF/DB 100 ton press. The superplastic die set used for the present study wa