References: 1)Jose Tom Tharappel and Jalumedi Babu 2018 IOP Conf. Ser.: Mater. Sci. Eng. 330 012082

1. M.Bala Gayathri
INCONEL 718

2. What is a Super Alloy
Superalloys are heat-resisting alloys based
on nickel, nickel-iron, or cobalt that exhibit
a combination of mechanical strength and
resistance to surface degradation.

3. Classification of Super alloys
Based on chemical composition
● Iron Base
● Cobalt Base
● Nickel Base
Based on Processing Methods
● Wrought alloys
● Cast alloys

4. Nickel- Based SuperAlloys
Nickel-based superalloys belong to a special class of high-
performance alloys characterised by a significant amount of nickel.
● They also contain Cr,Co,Fe,Mo,W and Ta as major alloying
elements.
● They are strengthened by solid solution and second phase
intermetallic precipitation.

5. ● Large number of alloying elements are added to derive
the best combination of mechanical properties at elevated
temperatures.
Examples: Hastelloy, Inconel, Waspaloy, Rene alloys, Incoloy,
MP98T, TMS alloys, and CMSX single crystal alloys
Waspaloy Inconel 625 Rene Alloy

6. Inconel 718
Alloy 718

7. Inconel 718
Inconel 718 is a special type of high-strength superalloy with a
nickel-chrome base that makes it resistant to corrosion, high
pressure and extreme temperatures of up to 700°C.
The material is composed of 50-55 % nickel, 17-21%
chromium, 4.75-5.5 % niobium and tantalum, and trace amounts
of molybdenum, titanium, cobalt, aluminium, manganese,
copper, silicon and other elements.

8. Characteristic Features of Inconel 718

9. 1. Temperature resistance
With a melting point of 1430°C, Inconel 718 showcases effective resistance to
heat and high temperatures. It also works well in cryogenic conditions, which
shows the range of temperature resistance that this material possesses.
1. Natural heat protection
This nickel superalloy has an intrinsic ability to create a strong and stable oxide
layer when exposed to heat. This natural passivation feature protects the material
against damage.
1. Corrosion resistance
The protective oxide layer gives this Inconel variant a significant amount of
resistance to oxidation, thereby protecting it from corrosion.

10. 4. High mechanical strength
At room temperature, the superalloy material exhibits a minimum of 725
MPa yield strength and 1035 MPa tensile strength. When Inconel 718
undergoes solution and precipitation treatment, these figures increase to
1035 MPa and 1240 MPa, respectively.
5. Exceptional welding quality
Other Inconel alloys are difficult to weld due to brittleness and cracking at
the exact welding point. However, Inconel 718 has been created to address
this issue, whether electron-beam or arc welding is used.

11. 6. Good malleability and machining quality
Most Inconel alloys tend to experience strain hardening when
machining or shaping is attempted. Inconel 718 is different-- it’s
easier to machine using a hard cutting implement through a slower
cutting mechanism.

12. Welding Processes applied on Inconel 718
● LW
● EBW
● GTAW
● FW
● CMT
● MIG

13. LW(Laser Welding)
● CO2 Laser, Pulser Laser & Fibre Laser
● Grain Boundary Liquation
EBW(Electron Beam Welding)
● Grain Size increment
● Laves phases
● PWST & PWHT

14. GTAW(Gas Tungsten Arc Welding)
● Activating fluxes Penetration,weld depth to width ratio.
Hot cracking conditions
FW(Friction Welding)
● Tensile Properties
CMT & MIG
● BrittlePhases
● Smaller width of HAZ

15. Applications of Inconel 718
AEROSPACE INDUSTRY
● Jet engines, gas turbines, space re-entry vehicles, rocket
technology reactors.

16. Applications of Inconel 718
MARINE APPLICATIONS
● Gas turbines, combustors, propeller shafts.

17. Applications of Inconel 718
POWER PLANTS
● Reactor springs, fuel element recovery.
PROCESSING INDUSTRY
● Shipping Drums, Processing Equipment

18. Conclusion
Because of its unique properties, Inconel 718 has become useful in a wide
range of applications ranging from manufacturing operations to military
equipment and the aerospace industry.

19. THANK YOU