Seamless Inconel 718 Pipe
Distinguished by its precipitation-hardening capabilities, our Inconel 718 tubing offers superior resistance to creep-rupture and high tensile strength at temperatures ranging from cryogenic levels up to 704°C (1300°F). This makes them indispensable for mission-critical applications in aerospace engines, high-strength fasteners, and downhole oil & gas tools. Through advanced cold-drawing and precise vacuum heat treatment, GZH ensures every pipe maintains optimal microstructure and excellent weldability without post-weld cracking, even in aggressive corrosive media.
"Our Inconel 718 pipes offer exceptional resistance to chloride and sulfide stress corrosion cracking, meeting NACE MR0175 standards."
What Is a Seamless Inconel 718 Pipe?
Seamless Inconel 718 pipe is a high-strength, corrosion-resistant pipe crafted from a single, solid billet of a nickel-chromium-iron superalloy. It is manufactured without a weld joint, ensuring superior structural integrity and reliability, especially under high-stress, high-temperature, and extremely corrosive conditions. The"Inconel 718"designation refers to a specific grade that is a precipitation-hardenable alloy. Its unique composition, which includes controlled amounts of niobium and molybdenum, allows it to be heat-treated to achieve exceptional strength and toughness from cryogenic temperatures up to 1300°F (704°C). This makes it a top choice for demanding applications in the aerospace, power generation, and oil and gas industries.
Key Features and Advantages
Inconel 718 Seamless Pipe offer a unique combination of benefits that make them invaluable in the most demanding industries:
Exceptional High Strength: The age-hardening heat treatment provides significantly higher tensile, yield, and creep-rupture strength than non-hardenable alloys, allowing for the use of thinner wall thicknesses and reduced material costs in high-pressure applications.
Outstanding Corrosion Resistance: It provides excellent resistance to chloride-ion stress-corrosion cracking, pitting, and crevice corrosion, particularly in sour gas and saltwater environments.
High Pressure and Temperature Tolerance: The seamless construction and robust material allow the pipe to safely handle high internal pressures and a wide range of operating temperatures.
Good Weldability: The alloy can be welded using standard methods, and subsequent heat treatment can restore the desired mechanical properties.
Versatility: Its combination of high strength and exceptional corrosion resistance makes it a highly versatile material for a wide range of applications.
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 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, corrosive 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) |
Table 4: The Standard of Seamless Inconel 718 Pipe ASTM B829 Size Tolerance Chart (mm):
| 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 of Seamless Inconel 718 Pipe
The combination of high strength and exceptional corrosion resistance of seamless Inconel 718 pipes makes them a preferred choice for:
Aerospace: Used in jet engines, rocket motors, and airframe components.
Oil and Gas Industry: For downhole components, wellhead equipment, and other parts in sour gas service and high-pressure applications.
Power Generation: In components for nuclear reactors, gas turbines, and other high-temperature applications.
Pumps and Valves: In the chemical and process industries for components requiring both high strength and corrosion resistance.
Manufacturing Process of Inconel Seamless Pipe
The manufacturing of a seamless Inconel 718 pipe 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 pipe is solution annealed and then age-hardened to achieve its specified metallurgical and mechanical properties.
- Finishing: The pipe 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 pipe is built to withstand the most demanding applications.
