Friction Stir Welding of Super Duplex Stainless Steel of UNS S32750, Its Microstructure Evaluation, Mechanical and Corrosion Properties

Authors

1 1- Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran

2 2- Department of Mechanical Engineering, University of Bonab, Azarbayzan Sharghi, Iran

3 3- Department of Mechanical Engineering, University of Saskatchewan, Canada

Abstract

Super duplex stainless steel is a kind of duplex stainless steel that has pitting resistant equivalent number over than 40. Unified Numbering System (UNS) S32750 is a common super duplex stainless stee, that is mostly applied in oil and gas refinery industries, because of its proper corrosion-resistant properties . Therefore, joining of these steels by welding is very important, but the greatest problem in this regard is the corrosion and decrease in mechanical properties after welding.. In this research, UNS S32750has been joined by friction stir welding method. The tool being used in this research was a WC with 16mm shoulder diameter, 5 mm pin diameter, and 1.9 mm height. X-ray diffraction showed that harmful phases, such as sigma or chi have not been formed. Microstructure study indicated that grain size in the stir zone has decreased. Vickers Hardness Test Method has been applied on welded samples. Moderate microhardness of base metal was 285 Vickers but, the microhardness increased in the stir zone to 360 Vickers, because of decreasing the grain size. The cyclic polarization determined that potential and corrosion current of joint metal by friction stir welding method was similar to base metal. Also, it was revealed that ferrite percentage in the stir zone doesn't decrease very much because the friction stir welding heat input is very low and the colding rate is very high.
 

Keywords

References

1. Lippold, J. C., and Kotecki, D. J., Welding Metallurgy and Weldability of Stainless Steels, Vol. 13, 1999.
2. Petterson, C. O., and Fager, S. A., “Welding Practice for the Sandvik Duplex Stainless Steels SAF 2304, SAF 2205 and SAF 2507”, AB Sandvik Steel Sweden, 1995.
3. Fager, S. A., and Odegard, L., “Welding of the Super Duplex Stainless Steel Sandvik SAF2507 (UNS S32750)”, Proceedings of the Third International Offshore and Polar Engineering Conference, Sweden, 1993.
4. Muthupandi, V., Bala Srinivasan, P., Seshadri, S. K., and Sundaresan, S., “Effect of Weld Metal Chemistry and Heat Input on the Structure and Properties of Duplex Stainless Steel Welds”, Materials Science and Engineering A, Vol. 358, pp. 9-16, 2003.
5. Chavdarov, P., “Electron Beam Welding of Super duplex Stainless Steel UNS S32750”, Stainless Steel World 2007 Conference, Netherlands, 2007.
6. Saeid, T., Abdollah-zadeh, A., Assadi, H., and Malek Ghaini, F., “Effect of Friction Stir Welding Speed on the Microstructure and Mechanical Properties of a Duplex Stainless Steel”, Materials Science and Engineering A, Vol 496, pp. 262-268, 2008.
7. Sato, Y. S., Nelson, T. W., Sterling, C. J., Steel, R. J., and Pettersson, C.-O., “Microstructure and Mechanical Properties of Friction Stir Welded SAF 2507 Super Duplex Stainless Steel”, Materials Science and Engineering A, Vol. 397, pp. 376-384, 2005.
8. Saeid, T., Abdollah-Zadeh, A., Shibayanagi, T., Ikeuchi, K., and Assadi, H., “On the Formation of Grain Structure During Friction Stir Welding of Duplex Stainless Steel”, Materials Science and Engineering A, Vol. 527, pp. 6484-6488, 2010.
9. Esmailzadeh, M., Shamanian, M., Kermanpur, A., and Saeid, T., “Microstructure and Mechanical Properties of Friction Stir Welded Lean Duplex Stainless Steel”, Materials Science & Engineering A, Vol. 561, pp. 486-491, 2013.
10. Nadana, R., Debroy, T., and Bhadeshia, H. K. D. H., “Recent Advances in Friction Stir Welding- Process, Weldment Structure and Properties”, Progress in Material Science, Vol. 53, pp.980-1023, 2008.
11. Mishra, R. S., and Mahoney, M. W., Friction Stir Welding and Processing, ASM International, USA, 2007.
13. Frigaard, Q., Grong, Q., and Midling, O. T., “A Process Model for Friction Stir Welding of Age Hardening Aluminum Alloys”, Metallurgical and Materials Transactions A, Vol. 32, pp. 1189-1200, 2001.
14. Hemmer, H., Grong, Q., and Klokkehaug, S., “A Process Model for the Heat-Affected Zone Microstructure Evolution in Duplex Stainless Steel Weldments”, Welding Metallurgical and Materials Transactions A., Vol. 31, pp. 1035-1048, 2000.
16. Humphreys, F. J., and Hatherly, M., Recrystallization and related annealing phenomena, 2nd Ed, Elsevier, 2004.
17. Cervo, R., Ferro, P., Tiziani, A., and Zucchi, F., “Annealing Temperature Effects on Super Duplex Stainless Steel UNSS32750 Welded Joints. II: Pitting Corrosion Resistance Evaluation” Journal of Materials Science, Vol.45, pp.4378-4389, 2010.
18. Horng, Y., Rong, I., and Wen, T., “Microstructure and Pitting Corrosion in Simulated Heat-Affected Zones of Duplex Stainless Steels” Materials Chemistry and Physics, Vol. 74, pp. 33-42, 2002.
19. Tiago, F., “Microstructure Evaluation of UNS S32205 Duplex Stainless Steel Friction Stir Welds” 10th Brazilian Stainless Steel Conference, Rio de Janeiro, Brazil, Vol. 66, pp. 187-191, 2013.
20. Santos, T., Queiroz1, R., and Ramirez, A., “Correlating Microstructure and Performance of UNS S32750 and S32760 Super Duplex Stainless Steels Friction Stir Welds” Proceedings of the Twenty-first International Offshore and Polar Engineering Conference, Rhodes, Greece, pp. 535-540, 2011.
21. Eghlimi, A., Shamanian, M., and Raeissi, K., “Effect of Current Type on Microstructure and Corrosion Resistance of Super Duplex Stainless Steel Claddings Produced by the Gas Tungsten Arc Welding Process”, Surface & Coatings Technology, Vol. 244, pp. 45-51, 2014.
Journal of Advanced Materials in Engineering (Esteghlal)
Volume 36, Issue 1
June 2017
Pages 97-120

Files

Share

How to cite

Statistics

تحت نظارت وف ایرانی