Inconel 718 tubes have become a top choice for industries that require strength, durability, and resistance to extreme conditions. Known for their outstanding performance in high-stress and high-temperature environments, these tubes are widely used in aerospace, power generation, chemical processing, and more.
This blog will help you understand the properties, advantages, and key applications of Inconel 718 tubes. If you’re looking for materials that can perform reliably under tough conditions, Inconel 718 may be the solution you need.
What Is Inconel 718?
Inconel 718 is a nickel-chromium alloy with additions of iron, niobium, molybdenum, titanium, and aluminum. It belongs to the Inconel family of superalloys, known for their exceptional resistance to oxidation and corrosion.
What sets Inconel 718 apart is its high strength and excellent weldability. Unlike other nickel alloys, Inconel 718 can be age-hardened, meaning its strength increases over time and under heat treatment.
Key Chemical Composition of Inconel 718
- Nickel (Ni): 50–55%
- Chromium (Cr): 17–21%
- Iron (Fe): Balance
- Niobium + Tantalum: 4.75–5.5%
- Molybdenum (Mo): 2.8–3.3%
- Titanium (Ti): 0.65–1.15%
- Aluminum (Al): 0.2–0.8%
This carefully balanced chemistry offers outstanding mechanical properties and corrosion resistance.
Mechanical Properties of Inconel 718 Tubes
- Tensile Strength: Up to 1,250 MPa
- Yield Strength: Approx. 1,000 MPa
- Melting Point: 1,260–1,330°C
- Hardness: Rockwell C35–45 (after aging)
- Excellent Fatigue Resistance
- Good Creep and Rupture Strength
These properties make Inconel 718 tubes ideal for use in extreme conditions involving high pressure and temperature.
Top Features of Inconel 718 Tubes
1. High-Temperature Resistance
Inconel 718 tubes perform exceptionally well at temperatures up to 700°C. They retain their strength and structure, even after prolonged exposure to heat, making them suitable for jet engines, exhaust systems, and gas turbines.
2. Excellent Corrosion Resistance
These tubes resist oxidation, pitting, and crevice corrosion in harsh chemical environments. Whether exposed to acids, seawater, or extreme humidity, Inconel 718 remains reliable.
3. Superior Weldability
Unlike many high-strength nickel alloys, Inconel 718 offers great weldability. It doesn’t crack or distort easily during welding, which reduces fabrication time and costs.
4. High Fatigue and Creep Strength
Inconel 718 tubes are ideal for cyclic loading and long-term use in high-stress environments. Their ability to resist fatigue, stress corrosion cracking, and creep makes them suitable for critical aerospace and nuclear applications.
5. Age-Hardening Capability
The alloy can be hardened through precipitation heat treatment. This allows manufacturers to adjust the hardness and strength as per specific requirements.
Applications of Inconel 718 Tubes
1. Aerospace Industry
Inconel 718 is a preferred material for aircraft engines, turbine blades, and afterburners. Its resistance to heat and fatigue ensures long-term performance under intense pressure and high temperatures.
2. Oil and Gas Industry
Inconel 718 tubes are used in downhole tools, wellhead components, and piping systems exposed to sour gas. Their ability to withstand high-pressure and corrosive fluids makes them indispensable in offshore and deep drilling operations.
3. Power Generation
Tubes made from Inconel 718 are often used in gas turbines, steam lines, and nuclear reactors. Their long service life reduces the frequency of maintenance and part replacement.
4. Chemical Processing
Inconel 718’s resistance to acid attack and oxidizing agents makes it perfect for heat exchangers, condensers, and reactors in chemical plants.
5. Marine Industry
Inconel 718 tubes are excellent for applications involving seawater and salt spray. Marine equipment, propeller shafts, and subsea hardware benefit from their corrosion resistance.
Manufacturing and Sizing Options
Inconel 718 tubes come in different forms to meet varying industrial needs:
- Seamless Tubes
- Welded Tubes
- Heat Exchanger Tubes
- Boiler Tubes
Common Sizes:
- Outer Diameter: 6 mm to 101.6 mm
- Wall Thickness: 0.5 mm to 12.7 mm
- Length: Custom lengths available (standard: up to 6 meters)
Manufacturers can also provide custom tube dimensions and finishes to suit your project requirements.
Standards and Specifications
Inconel 718 tubes are manufactured under strict industry standards to ensure quality and reliability:
- ASTM B163 / B516 / B983
- ASME SB163 / SB516 / SB983
- AMS 5589 / AMS 5590
These specifications cover various mechanical tests, dimensional tolerances, and heat treatment conditions to ensure consistent quality.
Tips for Selecting a Reliable Inconel 718 Tube Supplier
- Check Certifications: Look for suppliers with ISO 9001 and ASME certifications.
- Review Testing Procedures: Reputable suppliers perform PMI testing, ultrasonic testing, and hydro testing.
- Customization Options: Choose a manufacturer who can deliver custom sizes and coatings.
- Delivery Time & Logistics: On-time delivery is critical, especially for project-based industries.
- Technical Support: Ensure the supplier can provide technical guidance and documentation.
Conclusion
Inconel 718 tubes are an ideal choice for industries that operate under extreme conditions. Their combination of strength, heat resistance, and corrosion resistance makes them one of the most reliable materials in demanding environments.
Whether you’re in aerospace, oil and gas, or chemical processing, investing in Inconel 718 tubes ensures high performance, lower maintenance, and long service life. Always work with a trusted supplier to get quality products tailored to your needs.
