Laser Beam Welding of IN792 DS Superalloy

Abstract:

The main purpose of the investigation is to develop reliable methods to repair IN 792 superalloy components by Laser Beam Welding (LBW). The jet engine structural components made of nickel-base superalloys are subjected to high stresses and severe environmental, therefore crack may occurs during in-service life. Considering the high cost of this components they are often repaired by welding. Welds must be made: (i) by altering as little as possible the original microstructure; (ii) without introducing in the molten (MZ) and heat affected (HAZ) zones relevant residual stresses; (iii) without producing cracks in MZ and HAZ; (iv) without massive chemical segregation; (v) without elemental diffusion changing the composition of g and g’ phases.LBW has been used to realize seams on 2mm-thick plates of directionally solidified (DS) IN792 superalloy. An Yb fiber laser has been employed in present experiments and the molten pool was shielded from oxidation through a patented equipment. A grid of samples has been prepared by varying the pass speed v from 1 to 2.0 m/min with pre-heating temperature of 200 °C. The microstructural changes occurring in the microstructure of molten zone (MZ) and heat affected zone (HAZ) have been investigated by optical and scanning electron microscopy (SEM) observations and energy dispersion spectroscopy (EDS).

• Periodical: Materials Science Forum (Volume 941)
• Pages: 1149-1154
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.1149
• Online since: December 2018
• Authors: Giuseppe Barbieri, Francesco Cognini, Vincenzo Bonaiuto*, Roberto Montanari, Maria Richetta, Alessandra Varone
• Keywords: INS 792, Laser Welding, Nickel Superalloy

References

[1] R.C. Reed, The superalloys: fundamentals and applications,, Cambridge University Press, (2006).

[2] M. Tresa Pollock, T. Sammy in Nickel-Based Superalloys for Advanced Turbine Engines: Chemistry, Microstructure, and Properties,, University of Michigan, Ann Arbor, Michigan 48109, University of Cambridge, Cambridge, England CB2 3QZ, United Kingdom, (2006).

[3] S.A. David, J.M. Vitek, S.S. Babu, Welding of nickel base superalloy single crystals, ORNL TN 37831-6095.

[4] O.A. Ojo, N.L. Richards, M.C. Chaturvedi, Microstructural study of weld fusion zone of TIG welded IN 738LC nickel-based superalloy, Scripta Materialia 51 (2004) 683-688.

DOI: 10.1016/j.scriptamat.2004.06.013

[5] M.B. Henderson, D. Arrell, M. Heobel, R. Larsson, G. Marchanty, Nickel-Based Superalloy Welding Practices for Industrial Gas Turbine Applications, Science and Technology of Welding and Joining 9 (2013)13-21.

DOI: 10.1179/136217104225017099

[6] R. Vilar and A. Almeida, Repair and manufacturing of single crystal Nibased superalloys components by laser powder deposition—A review , J. Laser Appl., Vol. 27, No. S1, February (2015).

DOI: 10.2351/1.4862697

[7] Huei-Sen Wang, at all Microstructure Evolution of Laser Repair Welded Rene, 77 Nickel-Based Superalloy Cast Materials Transactions, Vol. 52, No. 12 (2011) p.2197 to 2204.

DOI: 10.2320/matertrans.m2011264

[8] Jinxia Yang, Qi Zheng, Hongyu Zhang, Xiaofeng Sun, Hengrong Guan, Zhuangqi Hu, Effects of heat treatments on the microstructure of IN792 alloy,, Materials Science and Engineering: A, Volume 527, Issues 4–5, 2010, Pages 1016-1021.

DOI: 10.1016/j.msea.2009.10.026

[9] G. Barbieri et al., IN792 DS Superalloy: Optimization of EB Welding and Post-Welding Heat Treatments,, Materials Science Forum, Vol. 879, pp.175-180, (2017).

DOI: 10.4028/www.scientific.net/msf.879.175

[10] G. Angella, G. Barbieri, R. Donnini, R. Montanari, M. Richetta, A. Varone, Electron Beam Welding of IN792 DS: Effects of Pass Speed and PWHT on Microstructure and Hardness,, Materials, 2017, 10, 9, 1033.

DOI: 10.3390/ma10091033

[11] R. Montanari, A. Varone, G. Barbieri, P. Soltani, A. Mezzi, S. Kaciulis, Welding of IN792 DS superalloy by electron beam,, Surf. Interface Anal., 2016, 48: 483–487.

DOI: 10.1002/sia.5946

[12] Zhenguo Jiang, at all, Comparative study on fiber laser welding of GH3535 superalloy in continuous and pulsed waves,, Materials & Design, Volume 110, 2016, Pages 728-739.

DOI: 10.1016/j.matdes.2016.08.055