Inconel 718 Pipe Fittings
Inconel 718 Pipe Fittings
Inconel 718 Pipe Fittings are manufactured from a nickel-chromium alloy strengthened by niobium, molybdenum, and titanium. Known for its outstanding combination of high tensile strength, excellent creep resistance, and superior corrosion stability, Inconel 718 is widely used in high-temperature and high-pressure environments. These pipe fittings offer exceptional performance from cryogenic temperatures up to 1300°F (705°C), making them ideal for aerospace, nuclear, petrochemical, and extreme industrial applications.
Key Features
Exceptional High-Temperature Strength up to 1300°F (705°C).
Outstanding Creep & Rupture Resistance due to precipitation hardening.
Excellent Corrosion & Oxidation Resistance in severe environments.
Superior Fatigue, Stress-Corrosion & Chloride Resistance.
Wide Operating Temperature Range: Cryogenic to high-temperature service.
Excellent Fabrication Properties – easy to form, machine & weld.
High Stability After Welding without the risk of post-weld cracking.
Specification
| Specification | Details |
|---|---|
| Material | Inconel Alloy 718 |
| Standard | ASTM B366 / ASME SB366 |
| UNS Number | UNS N07718 |
| Werkstoff Nr. | 2.4668 |
| Manufacturing Type | Seamless / Welded / Fabricated |
| Size Range | ½” to 24” |
| Wall Thickness | SCH 5S to SCH XXS |
| Dimensions | ASME B16.9, B16.28, MSS-SP-43 |
| Type | Buttweld, Socket Weld, Threaded |
| Forms Available | Elbow, Tee, Reducer, Cap, Cross, Stub End, Bends |
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | N07718 |
| Werkstoff Nr. | 2.4668 |
| EN | NiCr19Fe19Nb5Mo3 |
| BS | NA 51 |
| AFNOR | NC19FeNb |
Available Sizes
Buttweld Fittings: ½” – 24”
Socket Weld Fittings: ⅛” – 4”
Threaded Fittings: ⅛” – 4”
Custom manufacturing available upon request.
Chemical Composition
| Element | % |
|---|---|
| Nickel (Ni) | 50.0 – 55.0 |
| Chromium (Cr) | 17.0 – 21.0 |
| Iron (Fe) | Balance |
| Niobium + Tantalum (Nb+Ta) | 4.75 – 5.5 |
| Molybdenum (Mo) | 2.8 – 3.3 |
| Titanium (Ti) | 0.65 – 1.15 |
| Aluminum (Al) | 0.2 – 0.8 |
| Cobalt (Co) | 1.0 max |
| Carbon (C) | 0.08 max |
| Manganese (Mn) | 0.35 max |
| Silicon (Si) | 0.35 max |
| Sulfur (S) | 0.015 max |
| Copper (Cu) | 0.30 max |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 1275 MPa (min) |
| Yield Strength (0.2% Offset) | 1035 MPa (min) |
| Elongation | 12–20% |
| Hardness | 36 HRC (max) |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.19 g/cm³ |
| Melting Point | 1260 – 1336°C |
| Thermal Conductivity | 11.4 W/m·K |
| Electrical Resistivity | 1.29 μΩ·m |
| Specific Heat | 435 J/kg·K |
| Modulus of Elasticity | 205 GPa |
Types of Inconel 718 Pipe Fittings
Buttweld Fittings
45° / 90° / 180° Elbows
Equal & Reducing Tees
Concentric & Eccentric Reducers
Stub Ends (Short / Long)
End Caps
Cross Fittings
Long / Short Radius Bends
Socket Weld Fittings
SW Elbows
SW Tees & Cross
SW Couplings
SW Reducers
Threaded Fittings (NPT/BSP)
Threaded Elbows
Threaded Tees
Bushings
Plugs & Caps
Corrosion Resistance
Inconel 718 provides outstanding corrosion resistance in:
Oxidizing & reducing environments
Salt, seawater & chloride-containing media
High-temperature oxidation & carburization
Acids including sulfuric, nitric, phosphoric
Stress-corrosion cracking and pitting environments
Its unique niobium strengthening offers stability in extreme operating conditions.
Heat Resistance
Excellent resistance at temperatures up to 1300°F (705°C)
High creep & stress rupture strength
Outstanding oxidation resistance
Maintains structural strength during thermal cycling
Suitable for components exposed to high-heat exhaust, turbine, or furnace environments
Heat Treatment
Inconel 718 is age-hardenable.
Solution Annealing
980–1010°C followed by rapid cooling.
Aging Treatment
720°C for 8 hours, furnace cool to 620°C, hold for 8 hours, and air cool.
Heat treatment develops maximum mechanical strength for critical services.
Welding
Inconel 718 offers excellent weldability without hot cracking.
Welding Methods:
GTAW (TIG)
GMAW (MIG)
SMAW
Electron Beam Welding
Recommended Filler:
ERNiFeCr-2 (Inconel 718 filler wire)
Post-weld heat treatment may be required for high-strength applications.
Fabrication
Good machinability and formability
Easily forged, hot-worked, and cold-worked
Hot working temperature: 954–1204°C
Cold working increases strength and precision
Suitable for CNC machining, bending, and cutting
Applications
Aerospace turbines & jet engines
Nuclear reactors
Cryogenic storage tanks
High-temperature chemical processing
Oil & gas and offshore platforms
Heat exchangers & high-pressure piping
Rocket motors & propulsion systems
Power generation equipment