MSA  Vol.2 No.10 , October 2011
Effect of Laser Beam Welding Parameters on Microstructure and Properties of Duplex Stainless Steel
ABSTRACT
The present study is concerned with laser beam welding and its effect on size and microstructure of fusion zone then, on mechanical and corrosion properties of duplex stainless steel welded joints. In this regard, influence of different laser welding parameters was clarified. Both bead-on-plate and autogenously butt welded joints were made using carbon dioxide laser with a maximum output of 9 kW in the continuous wave mode. Welded joints were subjected to visual, dye penetrant and radiography tests before sectioning it for different destructive tests. Accelerated corrosion test was carried out based on tafel plot technique. The results achieved in this investigation disclosed that welding parameters play an important role in obtaining satisfactory properties of welded joint. High laser power and/or high welding speed together with adjusting laser focused spot at specimen surface have produced welded joints with a remarkable decrease in fusion zone size and an acceptable weld profile with higher weld depth/width ratio. Besides, acceptable mechanical and corrosion properties were obtained. Using nitrogen as a shielding gas has resulted in improving mechanical and corrosion properties of welded joints in comparison with argon shielding. This is related to maintaining proper ferrite/austenite balance in both weld metal and HAZ in case of nitrogen shielding. As a conclusion, laser power, welding speed, defocusing distance and type of shielding gas combination have to be optimized for obtaining welded joints with acceptable profile as well as mechanical and corrosion properties.

Cite this paper
nullA. El-Batahgy, A. Khourshid and T. Sharef, "Effect of Laser Beam Welding Parameters on Microstructure and Properties of Duplex Stainless Steel," Materials Sciences and Applications, Vol. 2 No. 10, 2011, pp. 1443-1451. doi: 10.4236/msa.2011.210195.
References
[1]   B. I. Voronenko, “Austenitic-Ferritic Stainless Steels: A State-of-the Art Review,” Metal Science and Heat Treatment, Vol. 39, No. 9-10, 1997, pp. 428-437. doi:10.1007/BF02484228

[2]   A. Poznansky, C. S. Nalbone and J. D. Crawford, “The Corrosion Resistance of 25Cr-3.5Mo-6Ni and 25Cr 4.5Mo-6Ni Cast Duplex Stainless Steels,” Proceedings of International Conference, Duplex Stainless Steels, St. Louis, 25-28 October 1983, pp. 431-444.

[3]   N. Lopez, M. Cid and M. Puigalli, “Influence of σ-Phase on Mechanical Properties and Corrosion Resistance of Duplex Steels,” Corrosion Science, Vol. 41, No. 8, 1999, pp. 1615-1631. doi:10.1016/S0010-938X(99)00009-8

[4]   M. Tynell, “Applicability Range for a High Strength Duplex Stainless Steel in Deep Sour Oil and Gas Wells,” Proceedings of International Conference, Duplex Stain- less Steels, St. Louis, 25-28 October 1983, pp. 283-292.

[5]   H. Miyuki, T. Kudo, M. Koso, M. Miura and T. Moroishi, “25%Cr Containing Duplex Phase Stainless Steel for Hot Sea Water Applications,” Proceedings of International Conference, Duplex Stainless Steels, St. Louis, 25-28 October 1983, pp. 95-112.

[6]   S. M. Tavares, V. F. Terra, J. M. Pardal and M. P. Fonseca, “Influence of the Microstructure on the Toughness of a Duplex Stainless Steel UNS S31803,” Journal of Materials Science, Vol. 40, No. 1, 2005, pp. 145-154. doi:10.1007/s10853-005-5700-7

[7]   L. F. Svensson and B. Gretoft, “Properties-Microstructure Relationship for Duplex Stainless Steel Weld Metals,” Proceedings of International Conference, Duplex Stainless Steel, The Hague, 27-28 October 1986, paper 22.

[8]   M. Miura, T. Kudo, M. Tsuge, M. Kuso and T. Kobayashi, “Effect of Chemical Composition on Microstructure, Mechanical and Corrosion Properties of Duplex Stainless Steel Weldment,” Proceedings of International Conference, Duplex Stainless Steel, The Hague, 27-28 October 1986, paper 33C.

[9]   J. Dobranszky and J. Ginsztler, “Microstructural Stability of Duplex Stainless Steel Weldments,” Materials Science Forum, Vol. 561-565, 2007, pp. 2119-2122. doi:10.4028/www.scientific.net/MSF.561-565.2119

[10]   V. Muthupandi, P. B. Srinivasan, S. K. Seshadri and S. Sundaresan, “Effect of Weld Metal Chemistry and Heat Input on the Structure and Properties of Duplex Stainless Steels,” Materials Science Engineering: A, Vol. 358, No. 1-2, 2003, pp. 9-16. doi:10.1016/S0921-5093(03)00077-7

[11]   J. Honeycombe and T. G. Gooch, “Intergranular Attack in Welded Stress-Corrosion Resistant Stain?less Steels,” Welding Journal, Vol. 56, No. 11, 1977, pp. 339-s-353-s.

[12]   R. Mundt and H. Hoffmeister, “Effect of Chemical Composition and Weld Thermal Cycles on Phase Transformation and Microstructures of Ferrite-Austenite Steels,” Proceedings of International Conference, Stainless Steel, Gothenberg, 3-4 September 1984, pp. 315-322.

[13]   S. Jana, “Effect of Heat Input on HAZ Properties of Two Duplex Stainless Steels,” Journal of Materials Processing Technology, Vol. 33, No. 3, 1992, pp. 247-261. doi:10.1016/0924-0136(92)90211-A

[14]   B. Bonnefois, R. Blondeau and D. Catelin, “Control of the Ferrite Level in Duplex Stainless Steel Welds,” Proceedings of International Conference, Duplex Stainless Steel, The Hague, 27-28 October 1986, paper 6.

[15]   J. Ku, N. Ho and S. Tjong, “Properties of Electron Beam Welded SAF 2205 Duplex Stainless Steel,” Journal of Materials Processing Technology, Vol. 63, No. 1-3, 1993, pp. 770-775. doi:10.1016/S0924-0136(96)02721-5

[16]   A. El-Batahgy, “Effect of Laser Beam Welding Parameters on Fusion Zone Shape and Microstructure of Austenitic Stainless Steel,” Materials Letters, Vol. 32, No. 2-3, 1997, pp. 155-163. doi:10.1016/S0167-577X(97)00023-2

[17]   J. Nowacki and A. Lukojc, “Microstructural Transformations of Heat Affected Zones in Duplex Steel Welded Joints,” Materials Characterization, Vol. 56, No. 4-5, 2006, pp. 436-441. doi:10.1016/j.matchar.2006.02.007

[18]   T. Omura, T. Kushida and Y. Komizo, “Effect of Nitrogen Distribution on Rapid Solidification in Laser Welded Duplex Stainless Steels,” Welding International, Vol. 14, No. 4, 2000, pp. 288-294. doi:10.1080/09507110009549181

[19]   P. Bala Srinivasan, V. Muthupandi, W. Dietzel and V. Sivan, “Microstructure and Corrosion Behavior of Shielded Metal Arc Welded Dissimilar Joints Comprising Duplex Stainless Steel and Low Alloy Steel,” Materials Engineering and Performance, Vol. 15, No. 6, 2006, pp. 758. doi:10.1361/105994906X150902

[20]   G. Lothongkum, P. Wongpanya, S. Morito, T. Furuhara and T. Maki, “Effect of Nitrogen on Corrosion Behaviour of 28Cr-7Ni Duplex and Microduplex Stainless Steels in Air-Saturated 3.5 wt% NaCl Solution,” Corrosion Science, Vol. 48, No. 1, 2006, pp. 137-153. doi:10.1016/j.corsci.2004.11.017

 
 
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