Inconel® 718
Inconel 718 is a precipitation-hardenable nickel-chromium alloy. It combines exceptionally high tensile, yield, and creep-rupture strength at temperatures up to 1300°F (700°C) with excellent weldability, making it the most widely used superalloy in the aerospace industry.
- Common Forms: Round Bar, Flat Bar, Forgings, Sheet, Wire.
- Key Feature: Age-hardenable for extreme strength.
- Weldability: Resistant to post-weld cracking (unlike other hardenable alloys).
- Compliance: Meets AMS 5662 / AMS 5663 / API 6A.
Inconel 718 stands out because it solves the "weldability vs. strength" problem. While most precipitation-hardened alloys are prone to cracking during welding, the use of Niobium in 718 allows for a sluggish aging response, permitting welding without spontaneous hardening. It is the gold standard for high-stress aerospace and oilfield components.
Extreme Strength
Precipitation hardening (aging) treatments result in yield strengths above 150 ksi, maintaining integrity in high-stress environments up to 1300°F.
Excellent Weldability
Unique chemistry prevents strain-age cracking during welding, allowing for the fabrication of complex structures and repair of engine parts.
Cryogenic Properties
Exhibits outstanding tensile and impact properties even at cryogenic temperatures, making it suitable for liquid hydrogen and oxygen tanks.
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 50.0 - 55.0 |
| Chromium (Cr) | 17.0 - 21.0 |
| Niobium (Nb) + Ta | 4.75 - 5.50 |
| Molybdenum (Mo) | 2.80 - 3.30 |
| Titanium (Ti) | 0.65 - 1.15 |
| Aluminum (Al) | 0.20 - 0.80 |
| Iron (Fe) | Balance |
*Note: Niobium is the primary age-hardening element in 718.
| Product Form | Standards (ASTM / AMS / ASME) |
|---|---|
| Bar, Forgings, Rings | ASTM B637, AMS 5662 (Annealed), AMS 5663 (Aged) |
| Plate, Sheet, Strip | ASTM B670, AMS 5596 |
| Pipe & Tube | API 6A CRA, AMS 5589 |
| Property | Typical Values (Room Temp) |
|---|---|
| Tensile Strength | 185 - 210 ksi (1275 - 1450 MPa) |
| Yield Strength (0.2% Offset) | 150 - 180 ksi (1034 - 1240 MPa) |
| Elongation | 12 - 20 % |
| Hardness (Rockwell C) | 36 - 44 HRC |
*Note: These properties reflect material in the fully heat-treated (aged) condition (AMS 5663).
Jet Engines
Turbine disks, blades, casings, compressor blades, and shafts exposed to high heat and stress.
Oil & Gas
High-pressure downhole tools, wellhead components, and safety valves (API 6A CRA 718) requiring high strength.
Liquid Fuel Rockets
Cryogenic tankage, flow components, and high-pressure turbo pumps.
Nuclear Fuel
High-strength structural members used in nuclear fuel spacer grids.
Need Aerospace Grade Inconel 718?
We stock Inconel 718 round bar and sheet in both AMS 5662 (Annealed) and AMS 5663 (Aged) conditions. Contact us for certification details.
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