Indian Welding Journal

Open Access Open Access  Restricted Access Subscription Access
Open Access Open Access Open Access  Restricted Access Restricted Access Subscription Access

Effect of Delta Current Frequency (DCF) on Microstructure and Tensile properties of Gas Tungsten Constricted Arc (GTCA) welded Inconel 718 Alloy Joints


Affiliations
1 Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University , Annamalai Nagar 608002, Tamilnadu, India
2 Vikram Sarabhai Space Centre (VSSC), ISRO, Thiruvananthapuram 695022, Kerala, India
     

   Subscribe/Renew Journal


Inconel 718 is a nickel-based superalloy mostly used in high temperature applications in aerospace sector due to its extensive mechanical properties and weldability . Gas T ungsten Arc Welding (GT AW) process is widely used for joining of Inconel 718 alloy for cleaner , precise and high-quality welds. However , due to the high heat input and wider arc associated with this process, it is having certain metallurgical problems in welding, such as coarse dendritic structure and segregation of alloying elements in weld metal region which significantly reduces the mechanical properties of the joints. T o overcome these limitations, a newly developed Gas T ungsten Constricted Arc Welding (GTCAW) process is employed to join Inconel 718 alloy . It is the advanced configuration of GTAW process, based on magnetic arc constriction induced by high frequency pulsing of the current known as Delta Current. The main objective of this investigation is to study the effect of Delta Current Frequency (DCF) on the weldability of Inconel 718 alloy for its viability in aerospace applications. The joints welded at 4 kHz showed superior tensile properties due to the refinement of grains in fusion zone. Increase in DCF results in decrease in tensile properties of the joints due to the coarsening of dendritic fusion zone microstructure. It is attributed to the stacking of heat input during welding.

Keywords

Gas Tungsten Constricted Arc Welding, GTCAW, Delta Current Frequency, Inconel 718, T Ensile Properties, Microstructure.
User
Subscription Login to verify subscription
Notifications
Font Size

  • Gordine J (1970); Welding of Inconel 718, Welding Research Supplement, pp.531-537 .

  • Lund CH (1961) Physical Metallurgy of Nickel Base Superalloys, Defence Metals Information Centre (DMIC) Report 153, Battelle Memorial Institute, Ohio.

  • Lippold J, DuPont JC, DuPont JN, Kiser SD (2009); Welding Metallurgy and Weldability of Nickel Base Alloys, John Wiley and Sons, Inc. , New Jersey .

  • Gordine J (1970); Some Problems in Welding Inconel 718, Welding Journal, pp.480-484.

  • Wagner HJ, Hall A (1965), Physical Metallurgy of Alloy 718, Defence Metals Information Centre (DMIC), Report 217 , Battle Memorial Institute Columbus Ohio.

  • Radhakrishna CH, Prasad Rao K (1997); The formation and control of Laves phase in superalloy 718 welds, Journal of Materials Science 32, pp.1977-1984.

  • Janaki Ram GD, Reddy AV , Rao KP , Reddy GM (2005); Microstructure and mechanical properties of Inconel 718 electron beam welds, Materials Science and T echnology 21, pp.1132-1138.

  • Madhusudan Reddy G, Srinivasa Murthy C V , Srinivasa Rao K, Prasad Rao K (2009); Improvement of mechanical properties of Inconel 718 electron beam welds- influence of welding techniques and post weld heat treatment, International Journal of Advanced Manufacturing T echnology 43, pp.671-680.

  • Agilan M, Krishna CS, Manwatkar SK, Vinayan EG, Sivakumar D, Pant B (2004); Effect of Welding Processes (GT AW & EBW) and Solutionizing T emperature on Microfissuring T endency in Inconel 718 Welds, Materials Science Forum710, pp.603-607 .

  • Huang CA, Wang TH, Lee CH, Han WC (2005); A study of the heat-affected zone (HAZ) of an Inconel 718 sheet welded with electron-beam welding (EBW), Materials Science and Engineering: A 398, pp.275-281.

  • Leary RK, Merson E, Birmingham K, Harvey D, Brydson R (2010); Microstructural and microtextural analysis of InterPulse GTCAW welds in Cp-Ti and Ti-6Al-4V ,Materials Science and Engineering: A 527 , pp.7694-7705.

  • Sudarshan Rao G, Saravanan K, Harikrishnan G, Sharma VMJ, Ramesh Narayan P , Sreekumar K, Sinha P (2012); Local Deformation Behaviour of Inconel 718 TIG weld-o ments at Room T emperature and 550 C, Materials Science Forum, 710, pp.439-444.

  • Cortes R, Barragan ER, Lopez VH, Ambriz RR, Jaramillo D (2018); Mechanical properties of Inconel 718 welds performed by Gas T ungsten Arc welding, International Journal of Advanced Manufacturing T echnology , 94 (9-12), pp.3949-3961.

  • Rodríguez NK, Barragán ER, Lijanova IV , Cortés R, Ambriz RR, Méndez C, Jaramillo D (2017); Heat Input Effect on the Mechanical Properties of Inconel 718 Gas T ungsten Arc Welds, Proceedings of the 17th International Conferenceon New T rends in Fatigue and Fracture, pp.255-262.

  • Agilan M, Krishna CS, Manwatkar SK, Vinayan EG, Sivakumar D, Pant B (2004);Effect of Welding Processes (GT AW & EBW) and Solutionizing T emperature on Microfissuring T endency in Inconel 718 Welds, Materials Science Forum 710, pp.603-607 .

  • Reddy GM, Murthy CVS,Viswanathan N, Prasad Rao K (2007); Effects of electron beam oscillation techniques on solidification behaviour and stress rupture properties of Inconel 718 welds, Science and T echnology of Welding and Joining, 12, pp.106-114.

  • Mei Y , Liu Y , Liu C, Li C, Guo Q, Li H (2016); Effect of base metal and welding speed on fusion zone microstructure and HAZ hot cracking of electron beam welded Inconel 718, Materials and Design, 89, pp.964-977 .

  • Ram GDJ, Reddy A, Prasad Rao K, Madhusudhan Reddy G, Sarin Sundar J (2005); Microstructure and T ensile properties of Inconel 718 pulsed Nd-Yag Laser Welds, Journal of Materials Processing T echnology , 167 , pp.73-82.

  • Odabasi A, Unlu N, Goller G, Eruslu MN (2010); A Study on Laser Beam Welding (LBW) T echnique: Effect of Heat Input on the Microstructural Evolution of Superalloy Inconel 718, Metallurgical and Materials T ransactions A, 41, pp.2357-2365.

  • Cao X, Rivaux B, Jahazi M, Cuddy J, Birur A (2009); Effect of pre- and post-weld heat treatment on metallurgical and tensile properties of Inconel 718 alloy butt joints welded using 4 kW Nd-Yag laser welding, Journal of Material Science, 44, pp.4557-4571.

  • Sivaprasad K, Ganesh Sundara Raman S, Mastanaiah P , Madhusudhan Reddy G (2006); Influence of magnetic arc oscillation and current pulsing on microstructure and high temperature tensile strength of alloy 718 TIG weldments, Materials Science and Engineering A, 428, pp.327-331.

  • Ram GDJ, Venugopal Reddy , A, Prasad Rao K, Reddy GM (2004); Control of Laves phase in Inconel 718 GTA welds INDIAN WELDING JOURNAL Vol ume 53 No. 2, A pri l , 2020 with current pulsing, Science and T echnology of Welding and Joining, 9, pp.390-398.

  • Sonar T , Balasubramanian V , Malarvizhi S, Venkateswaran T , Sivakumar D (2019); Effect of Delta Current on the microstructure and tensile properties of Gas T ungsten Constricted Arc welded Inconel 718 alloy joints, Manufacturing T echnology T oday 8, pp.48-60.

  • Manikandan SGK, Sivakumar D, Kamaraj M, Prasad Rao K (2012); Laves phase control in Inconel 718 weldments, Material Science Forum, 710, pp.614-619.

  • Radhakrishna CH, Prasad Rao K (1997); The formation and control of Laves phase in superalloy 718 welds, Journal of Materials Science, 32, pp.1977-1984.

  • Sivaprasad K, Sundara Raman G (2008); Influence of weld cooling rate, on microstructure and mechanical properties of Alloy 718 weldments, Metallurgical and Materials T ransactions A, 39, pp.2115-2127 .

  • Manikandan SGK, Sivakumar D, Prasad Rao K, Kamaraj M (2014); Effect of weld cooling rate on Laves phase formation in Inconel 718 fusion zone, Journal of Materials Processing T echnology 214.


Abstract Views: 343

PDF Views: 7




  • Effect of Delta Current Frequency (DCF) on Microstructure and Tensile properties of Gas Tungsten Constricted Arc (GTCA) welded Inconel 718 Alloy Joints

Abstract Views: 343  |  PDF Views: 7

Authors

Tushar Sonar
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University , Annamalai Nagar 608002, Tamilnadu, India
V. Balasubramanian
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University , Annamalai Nagar 608002, Tamilnadu, India
S. Malarvizhi
Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University , Annamalai Nagar 608002, Tamilnadu, India
T. Venkateswaran
Vikram Sarabhai Space Centre (VSSC), ISRO, Thiruvananthapuram 695022, Kerala, India
D. Sivakumar
Vikram Sarabhai Space Centre (VSSC), ISRO, Thiruvananthapuram 695022, Kerala, India

Abstract


Inconel 718 is a nickel-based superalloy mostly used in high temperature applications in aerospace sector due to its extensive mechanical properties and weldability . Gas T ungsten Arc Welding (GT AW) process is widely used for joining of Inconel 718 alloy for cleaner , precise and high-quality welds. However , due to the high heat input and wider arc associated with this process, it is having certain metallurgical problems in welding, such as coarse dendritic structure and segregation of alloying elements in weld metal region which significantly reduces the mechanical properties of the joints. T o overcome these limitations, a newly developed Gas T ungsten Constricted Arc Welding (GTCAW) process is employed to join Inconel 718 alloy . It is the advanced configuration of GTAW process, based on magnetic arc constriction induced by high frequency pulsing of the current known as Delta Current. The main objective of this investigation is to study the effect of Delta Current Frequency (DCF) on the weldability of Inconel 718 alloy for its viability in aerospace applications. The joints welded at 4 kHz showed superior tensile properties due to the refinement of grains in fusion zone. Increase in DCF results in decrease in tensile properties of the joints due to the coarsening of dendritic fusion zone microstructure. It is attributed to the stacking of heat input during welding.

Keywords


Gas Tungsten Constricted Arc Welding, GTCAW, Delta Current Frequency, Inconel 718, T Ensile Properties, Microstructure.

References





DOI: https://doi.org/10.22486/iwj.v53i2.195584