Inconel 718 Pipe and Tube (UNS N07718)
Nickel-chromium alloy seamless pipe and tubing designed for high-temperature, high-pressure and corrosive environments. Widely used in aerospace, oil & gas, and chemical processing industries.
Request QuoteInconel 718 Pipe and Tube Product Forms
Comprehensive nickel alloy 718 / Inconel 718 tubing solutions covering seamless pipes, precision tubes, heat exchanger tubes, and engineered tubular forms for high-performance applications.
Seamless Pipe
High-pressure Inconel 718 pipe for oil & gas and chemical systems.
Welded Pipe
Cost-efficient 718 pipe option for medium-pressure applications.
Precision Tube
High-tolerance tubing for aerospace and instrumentation systems.
Heat Exchanger Tube
Thermal-resistant tubing for condensers and heat exchangers.
Capillary Tube
Small-diameter 718 tubes for precise fluid control systems.
U-Bent Tube
Custom bent tubing for compact heat transfer equipment.
Coiled Tube
Flexible coil form for instrumentation and control systems.
Instrumentation Tube
High-cleanliness tubing for measurement and control lines.
Custom Tube Solutions
Engineered 718 tubular products tailored to project requirements.
Inconel 718 Pipe and Tube Standards
Nickel alloy 718 pipe and tubing are manufactured in accordance with international ASTM/ASME specifications, ensuring high strength, corrosion resistance, and reliable performance in critical applications.
Material Specification
- UNS N07718 (Inconel 718)
- Nickel-Chromium-Iron Alloy
- Age-hardenable superalloy
- High temperature strength up to ~700°C
Pipe & Tube Standards
- ASTM B829 – Seamless Pipe & Tube
- ASTM B163 – Condenser & Heat Exchanger Tubes
- ASTM B444 – Nickel Alloy Pipe
- ASME SB series equivalents
Mechanical Properties (Typical)
- High tensile strength after aging
- Excellent fatigue resistance
- Good creep resistance at elevated temperature
- Stable performance under pressure cycling
Quality & Testing
- Hydrostatic test
- Ultrasonic testing (UT)
- Eddy current inspection
- Positive material identification (PMI)
Heat Treatment & Double Aging of Inconel 718
Inconel 718 is a precipitation-hardening nickel-based superalloy. Its mechanical properties are not fixed by composition alone, but are primarily developed through a controlled heat treatment process, especially solution treatment followed by double aging.
Double Aging Strengthening Mechanism
The double aging process promotes the precipitation of coherent γ'' (Ni₃Nb) and γ' phases within the γ matrix. These nanoscale precipitates create strong lattice strain fields that significantly hinder dislocation motion, which is the primary mechanism of plastic deformation in the alloy.
- First aging stage promotes nucleation of fine γ'' precipitates.
- Second aging stage controls growth and distribution stability of γ'' and γ' phases.
- γ'' (Ni₃Nb) is the dominant strengthening phase in Inconel 718.
Mechanical Property Improvement
After solution treatment and double aging, Inconel 718 achieves a significant increase in strength and hardness due to precipitation strengthening. At the same time, because the precipitates remain coherent with the FCC matrix, the alloy retains useful ductility and fracture resistance.
- Tensile strength: typically increased to ~1240–1500 MPa depending on condition
- Yield strength: significantly enhanced after aging treatment
- Hardness: increases substantially due to dense precipitate distribution
- Ductility: maintained due to coherent γ'' precipitation mechanism
Microstructural Basis
The strengthening effect is governed by the interaction between dislocations and coherent precipitates. γ'' (body-centered tetragonal Ni₃Nb) produces strong coherency strain with the FCC matrix, while γ' (Ni₃(Al,Ti)) contributes additional stability. The balance between these phases determines the final strength–ductility combination of the alloy.
Mechanical Properties of Inconel 718 (Aged Condition)
The mechanical properties of Inconel 718 are highly dependent on heat treatment. In the precipitation-hardened condition (solution treated + double aged), the alloy achieves its maximum strength level while maintaining usable ductility.
| Property | Typical Value (Aged Condition) |
|---|---|
| Tensile Strength (Rm) | 1240 – 1500 MPa (180 – 218 ksi) |
| Yield Strength (Rp0.2) | 1030 – 1300 MPa (150 – 190 ksi) |
| Elongation | 10 – 20 % |
| Hardness | 36 – 44 HRC (≈ 331–401 HB) |
| Modulus of Elasticity | ~200 GPa (29,000 ksi) |
Inconel 718 Pipe and Tube Applications
Inconel 718 tubing and pipe are widely used in extreme environments requiring high strength, corrosion resistance, and stability under high temperature and pressure.
Aerospace Engineering
Used in jet engines, exhaust systems, and fuel lines where high temperature strength and fatigue resistance are critical.
Oil & Gas Industry
Applied in downhole tubing, high-pressure pipelines, and subsea equipment exposed to corrosive environments.
Chemical Processing
Suitable for reactors, heat exchangers, and aggressive chemical transport systems.
Power Generation
Used in turbine components, boiler systems, and high-temperature steam lines.
Heat Exchange Systems
Ideal for condenser and heat exchanger tubing operating under thermal cycling conditions.
Marine & Offshore
Resistant to seawater corrosion, used in offshore platforms and marine engineering systems.
Inconel 718 Pipe and Tube Size Range
Standard and custom dimensions of Inconel 718 seamless and welded pipes and tubes, supplied according to ASTM B829 and related specifications.
| Product Form | Outer Diameter (OD) | Wall Thickness | Length | Standard |
|---|---|---|---|---|
| Seamless Pipe | 6 mm – 610 mm | 0.5 mm – 50 mm | Max 12 m | ASTM B829 / ASME SB829 |
| Welded Pipe | 6 mm – 1219 mm | 1 mm – 40 mm | Max 12 m | ASTM B775 / ASME SB775 |
| Seamless Tube | 3 mm – 219 mm | 0.3 mm – 20 mm | Max 18 m (coil optional) | ASTM B163 / B167 |
| Precision / Capillary Tube | 0.5 mm – 12 mm | 0.1 mm – 2 mm | Coil / Fixed length | ASTM B704 / B751 |
| U-Bent / Coiled Tube | 6 mm – 25 mm | 0.5 mm – 2.5 mm | Custom | ASTM B163 |
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