Study of the microstructure and metallurgical properties in tungsten inert gas welded Incoloy 925 superalloy
Subject Areas :
Ali
Mortazaei
1
(کارشناس ارشد، دانشکده مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی)
Ehsan
Ghajavand
2
(کارشناس ارشد، دانشکده مهندسی مواد، واحد نجف آباد، دانشگاه آزاد اسلامی)
Keywords: Mechanical Properties, Microstructure, Incoloy 925,
Abstract :
In this research, welding of Incoloy 925 nickel-iron based superalloy was examined in order to investigate the effect of chemical composition of used filler metals on the microstructure, mechanical properties and corrosion resistance of welded zones. For this purpose, shielding gas tungsten arc welding process and two nickel-base filler metals including ERNiCrMo-3 and ERNiCr-3 were used. Morphological observations showed that at the end of solidification, microstructure of weld metals were stabilized in the form of austenitic with dendritic morphology. In addition, in tensile test although tensile strength of weld metals were lower than Incoloy 925 base alloy but rupture in specimens occurred in heat-affected zone of base metal. In charpy impact test, ERNiCr-3 weld metal was broken by more attracting fracture energy compared to Incoloy 925 base metal and ERNiCrMo-3 weld metal. By performing potentiodynamic polarization test also determined that the corrosion potential difference between base metal and ERNiCrMo-3 weld metal can persuade occurrence of galvanic corrosion in the joint. Finally, with regard to the achieved results, ERNiCr-3 filler metal was diagnosed better selection for welding of Incoloy 925 superalloy.
[1] M. Durand, “The microstructure of superalloys”, Gordon and Breach, Amsterdam, 1997.
[2] M. J. Donachie & S. J. Donachie, “Superalloys a technical guide”, 2nd edition, ASM international, 2002.
[3] http://www.specialmetals.com/documents/Incoloy%20alloy%20925.pdf
[4] S. Kou, “Welding metallurgy”, second ed. Hoboken, John Wiley & Sons Inc, 2003.
[5] Standard mathhods for mechanical testing of welds, ANSI/AWS. Welding handbook B4.0M. American Welding Society Inc, 2006.
[6] Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements, ASTM G59-97, American Society for Testing and Materials, Vol. 03. 02: Corrosion of Metals, Wear and Erosion, 2014.
[7] J. N. Dupont, J. C. Lippold & S. D. Kiser, “Welding metallurgy and weldability of nickel-base alloys”, John Wiley, 2009.
[8] M. Qian & J. C. Lippold, “The Effect of Rejuvenation Heat Treatments on the Repair Weldability of Wrought Alloy 718”, Materials Scince and Engineering, Vol. 340A, pp. 225-231, 2003.
[9] [9] D. E. Nelson & E. A. Baeslack, “Morphology of weld heat-affected zone liquation in cast Alloy 718”, Scripta materialia, Vol. 19, pp. 371-379, 1986.
[10] M. J. Cieslak, T. J. Headley, A. D. Romig & T. Kollie, “A melting and solidification study of Alloy 625”, Metall Mater Trans, Vol. 19A, pp. 2319-31, 1981.
[11] M. J. Cieslak, T. J. Headley, T. J. Knorovsky, G. A. Romig & T. Kollie, “A comparison of the solidifi cation behavior on incoloy 909 and inconel 718”, Metallurgical Transactions, Vol. 21A, pp. 479-488, 1990.
[12] Winegard WC. An introduction to the solidification of metals. Institute of Metals, 1964.
[13] J. N. DuPont, C. V. Robino & A. R. Marder, “Solidification of Nb-bearing uperalloy”, Part II. Metallurgical and Materials Transactions, Vol. 29A, pp. 2797-2806, 1998.
[14] S. W. Banovic & J. N. DuPont, “Dilution and microsegregation in dissimilar metal welds between super austenitic stainless steels and Ni base alloys”, Science and Technology of Welding and Joining, Vol. 6, No. 6, pp. 274-383, 2003.
[15] J. N. DuPont, S. W. Banovic & A. R. Marder, “Microstructural evolution and weldability of dissimilar welds between a super austenitic stainless steel and nickel-ba ed Alloy” ,Welding Journal, Vol. 82, pp. 125-35, 2003.
ا. منشی، ع و ر.ضوی. "انجماد در جوشکاری"، انتشارات ارکان دانش، ١٣٨٧.