1. Introduce
– Polycrystalline precipitation hardening nickel-based superalloy for air engine disk applications
– Alloy designed to overcome the limitations of Inconel 718 and meet the enhanced operating conditions of jet engines
– Alloys designed to have the high temperature performance and thermal stability of Waspaloy alloys while maintaining the machining characteristics of Inconel 718
– Superior machining, formability, wear resistance, and weld crack resistance compared to Waspaloy and other high-temperature nickel-based alloys
→ A promising replacement for γ’ strengthened alloys such as Waspaloy or Udimet 720
– Typically applied to parts requiring creep and stress fracture resistance to 760°C and oxidation resistance to 982°C
– UNS N07818
* Inconel 718+ vs Inconel 718
– Inconel 718 Limitations: Lack of microstructural thermal stability above 650℃ due to γ” phase transformation at high temperatures
– The chemical composition of Inconel 718+ adds alloying elements (Co and Al) that promote precipitation of γ” phase instead of the unstable γ” phase
– Inconel 718+ : Can be operated at 55℃ higher temperature than Inconel 718
* Inconel
- Features
– Resists oxidation and submersion in oxidizing and sulfurizing atmospheres above 900℃
– Non-corrosive to organic and salt solutions
– Excellent mechanical properties such as tensile and yield strength up to about 600℃ - Applications
– High temperature heat resistant equipment(Heat treatment furnace, boiler, jet engine parts, electric heater parts) - Types
– Incoenl 600/601, Inconel 625, Inconel 690, Inconel 718, Inconel 718+, Inconel X-750, etc.
* Precipitation hardening Ni-based superalloys
– Most nickel-based superalloys are strengthened by precipitation of intermetallic compounds, primarily within the austenitic face cubic (FCC) base
– This is accomplished with elements such as Al, Ti, Nb, etc.
| Strenthening Phase | Type |
|---|---|
| γ’ strengthened nickel-based superalloys | Inconel 718+, Waspaloy, Astroloy, U-700, U-720 |
| γ” Reinforced nickel-based superalloys | Inconel 718 |
| γ’ and γ” strengthened superalloys | Inconel 706, Inconel 909 |
* UNS
- Abbreviation for Unified Numbering Systems for Metals and Alloys
- Unified unique numbering system for metals and alloys
- A representative number that is compatible with metals and alloys defined in many material-related codes such as ASTM, AISI, ASME, AWS, etc.
* N : Nickel and Nickel Alloys
* UNS N07818 : 07XXX : Chromium(Precipitation-hardenable alloy)
2. Property
– Excellent high temperature properties, processability, moldability, wear resistance, and crack resistance
– Improved temperature performance
| Element | Impact |
|---|---|
| Cr | Provides corrosion resistance, oxidation resistance |
| Co | Highly reinforced element, provides strength and creep properties |
| Nb | Highly strengthened element, provides high temperature strength |
| Mo | Highly strengthened element, provides high temperature oxidation resistance, cryogenic oxidation resistance, and weldability |
| W | Highly strengthening element, provides high temperature creep properties |
[Inconel 718+ Chemical Composition (%)]
| Ni | Cr | Fe | C | Al |
|---|---|---|---|---|
| 44.92 ~ 56.79 | 17.00 ~ 21.00 | 8.00 ~ 10.00 | 0.01 ~ 0.05 | 1.20 ~ 1.70 |
| Ti | Cu | Si | Mn | Mo |
|---|---|---|---|---|
| 0.50 ~ 1.00 | Max. 0.30 | Max. 0.35 | Max. 0.35 | 2.50 ~ 3.10 |
| Co | Nb | W | P | B |
|---|---|---|---|---|
| 8.00 ~ 10.00 | 5.20 ~ 5.80 | 0.80 ~ 1.40 | Max. 0.02 | Max. 0.01 |
[Inconel 718+ Mechanical Properties]
| Tensile Strength (Mpa) | Yield Strength (Mpa) | Elongation (%) |
|---|---|---|
| 1170 | 1170 | 25 |
[Inconel 718+ Physical Properties]
| Density (g/㎤) | Melting Range (℃) | Curie Temperature (℃) |
|---|---|---|
| 8.25 | 1260 ~ 1343 | -113 |
3. Standard & Specification
– Specification : UNS N07818
4. Available Form
– Bar, Rod
– Plate, Sheet, Strip
– Wire
– Forgings, Billets
5. Application & Product
– Aerospace
| Application | Product |
|---|---|
| Aerospace | Fasteners, Blades, Aircraft Engine Disks, Gas Turbine Engine Components, Turbine Casings, Combustors |
(1) Fasteners / (2) Blades / (3) Turbine Cases / (4) Combustors
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