Seamless Inconel 718 Tube
Distinguished by its precipitation-hardening capabilities, our Inconel 718 tubing offers exceptional yield strength and resistance to creep-rupture at temperatures up to 700°C (1300°F). This makes them indispensable for mission-critical applications in aerospace engine components, high-strength cryogenic vessels, and downhole oil & gas tools. Through advanced cold-drawing and precise vacuum heat treatment, GZH ensures every tube maintains optimal microstructure and superior resistance to post-weld cracking and corrosion in aggressive media.
What Is a Seamless Inconel 718 Tube?
SeamlessInconel 718 tube is a high-strength, corrosion-resistant tube crafted from a single, solid billet of a nickel-chromium-iron superalloy. Unlike welded tubes, it's manufactured without any weld joint, ensuring superior structural integrity and reliability, especially under high-stress, high-temperature, and highly corrosive conditions. The"Inconel 718"designation refers to a specific grade known for its remarkable tensile, creep, and rupture strength at elevated temperatures up to 1300°F (704°C). The alloy is also precipitation-hardenable, which allows its strength to be significantly increased through a controlled heat treatment process. This combination of properties makes it a top choice for critical applications in the aerospace, oil and gas, and power generation industries.
Key Features and Advantages
Inconel 718 Seamless Tube offer a unique combination of benefits that make them invaluable in the most demanding industries:
Exceptional High-Temperature Strength: Provides outstanding tensile, creep, and rupture strength at temperatures up to 1300°F (704°C), making it ideal for high-heat environments.
Excellent Corrosion Resistance: It offers good resistance to oxidation and corrosion in a wide range of corrosive media, including highly acidic and alkaline solutions.
Superior Weldability: Inconel 718 is relatively easy to weld without the risk of post-weld cracking, a key advantage for complex fabrications.
High Pressure Tolerance: The seamless construction eliminates a potential weak point, allowing the tube to safely handle high internal pressures, which is critical in many fluid transfer and structural applications.
Age-Hardenable: The ability to be precipitation-hardened provides a wide range of mechanical properties to suit different application requirements.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Inconel 718.
Table 1: Chemical Composition of Inconel 718
The composition of Inconel 718 is carefully balanced to achieve its superior high-temperature strength and corrosion resistance.
| Ni | Cr | Fe | Mn | Nb | Mo | Ti | C | Si | S | P | Co | B |
| 50.0- 55.0 | 17.00-21.00 | Bal | ≤0.35 | 4.75- 5.50 | 2.80- 3.30 | 0.65- 1.15 | ≤0.08 | ≤0.35 | ≤0.015 | ≤0.015 | ≤1.0 | ≤0.006 |
Table 2: Typical Mechanical Properties of Inconel 718
Inconel 718 is specifically designed to maintain its strength and shape in high-stress, high-temperature environments.
| Tensile Strength | Yield Strength | Elongation | Hardness |
| ≥ 1240 MPa | ≥ 1034 MPa | ≥ 12% | 38-45 HRC |
Table 3: Typical Physical Properties of Inconel 718
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
| 8.22 g/cm³ | 1260 - 1336 °C | 13.0 µm/m·°C (20-100°C) | 11.4 W/m·K (20°C) | 200 GPa | 1.2 x 10⁻⁶ Ω·m (20°C) |
| Nominal Outside Diameter, in. (mm) | Outside Diameter in. (mm) | Thickness of Specified Nominal Wall , % | Thickness of Specified Minimum Wall , % | |||
| Plus | Minus | Plus | Minus | Plus | Minus | |
| Over 0.400 (10) to 5/8 (16), excl | 0.005 (0.13) | 0.005 (0.13) | 15 | 15 | 30 | 0 |
| 5/8 (16) to 1 1/2 (38), incl | 0.0075 (0.19) | 0.0075 (0.19) | 10 | 10 | 22 | 0 |
| Over 1 1/2 (38) to 3 (76), incl | 0.010 (0.25) | 0.010 (0.25) | 10 | 10 | 22 | 0 |
| Over 3 (76) to 4 1/2 (114), incl | 0.015 (0.38) | 0.015 (0.38) | 10 | 10 | 22 | 0 |
| Over 4 1/2 (114) to 6 (152), incl | 0.020 (0.51) | 0.020 (0.51) | 12.5 | 12.5 | 28 | 0 |
| Over 6 (152) to 6 5/8 (168), incl | 0.025 (0.64) | 0.025 (0.64) | 12.5 | 12.5 | 28 | 0 |
| Over 6 5/8 (168) to 8 5/8 (219), incl | 0.031 (0.79) | 0.031 (0.79) | 12.5 | 12.5 | 28 | 0 |
Common Applications
The combination of high strength and exceptional corrosion resistance of seamless Inconel 718 tubes makes them a preferred choice for:
Aerospace: Used in jet engine components, gas turbines, and other parts exposed to extreme temperatures.
Oil and Gas Industry: In downhole equipment and wellhead components for sour gas service and high-pressure applications.
Power Generation: For high-temperature fasteners, shafts, and other components in turbines and power plants.
Cryogenic Applications: It maintains excellent mechanical properties at extremely low temperatures.
Manufacturing Process
The manufacturing of a Seamless Inconel Tube is a precise, multi-step process:
- Heating: A solid billet of Inconel 718 is heated to a high temperature.
- Hot extrusion: Hot extrusion is a metal forming process that shapes a metal billet by forcing it through a die at a temperature above its recrystallization temperature. This process softens the material, allowing for the creation of complex cross-sectional profiles with reduced force compared to cold extrusion, and it is commonly used to manufacture products like bars, tubes, and other special shapes from metals like aluminum, copper, and steel.
- Drawing and Sizing: The hollow shell is then rolled and drawn to reduce its diameter and wall thickness to the desired dimensions.
- Heat Treatment: The tube is solution treated and then age-hardened to achieve its final, high-strength properties.
- Finishing: The tube is cut to length, straightened, and subjected to rigorous testing to ensure it meets the highest standards for performance and reliability. This meticulous process ensures that every seamless Inconel 718 tube is built to withstand the most extreme operating conditions.
