Inconel 718
Strength: Possesses high tensile strength, fatigue strength, creep strength, and fracture strength.
Temperature Range: Performs excellently in a temperature range from cryogenic temperatures to approximately 1290°F (980°C).
Corrosion Resistance: Resistant to oxidation and stress corrosion cracking, and exhibits good corrosion resistance in acidic environments containing hydrogen sulfide/carbon dioxide.
Weldability: Offers superior resistance to post-weld cracking compared to other high-temperature alloys.
Heat Treatment: Optimal mechanical properties are achieved through age hardening, and different heat treatment processes can be used depending on the application requirements.
As a leading supplier and manufacturer in China, GNEE Steel provides cost-effective nickel-based alloy products.
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Inconel 718 description
GNEE Inconel 718
Inconel 718 (UNS N07718) is a high-strength, corrosion-resistant nickel-chromium superalloy known for its exceptional strength, fatigue resistance, and creep resistance at extreme temperatures (up to approximately 1290°F/980°C), and it maintains its properties over a wide range of temperatures from cryogenic to high temperatures. It can be strengthened by precipitation hardening, has good weldability, and is resistant to oxidation and corrosion, making it crucial in aerospace (jet engines, rockets), oil and gas (downhole tools), and petrochemical industries, where it is commonly used in fasteners, turbine components, and cryogenic equipment.
Inconel 718 Available Shape
Inconel 718 Seamless Pipe
Inconel 718 Plate
Inconel 718 Bar
Inconel 718 Pipe Fitting
Inconel 718 Standards and Specifications
| Standard | Description |
|---|---|
| ASTM B637 | Bars and Rods |
| ASTM B670 | Plates and Sheets |
| ASTM B673 | Seamless Tubes |
| AMS 5662 / AMS 5663 |
Fitting |
Inconel 718 Specification
Inconel 718 Chemical Composition
| Element | Composition (%) |
|---|---|
| Nickel (Ni) | 50.0 – 55.0 |
| Chromium (Cr) | 17.0 – 21.0 |
| Iron (Fe) | 18.5 min |
| Niobium (Nb) | 4.75 – 5.50 |
| Molybdenum (Mo) | 2.80 – 3.30 |
| Titanium (Ti) | 0.65 – 1.15 |
| Aluminum (Al) | 0.20 – 0.80 |
| Tantalum (Ta) | 0.05 max |
| Manganese (Mn) | 0.35 max |
| Silicon (Si) | 0.35 max |
| Carbon (C) | 0.08 max |
| Sulfur (S) | 0.015 max |
| Phosphorus (P) | 0.015 max |
| Copper (Cu) | 0.30 max |
Mechanical properties of Inconel 718 at different temperatures
| Property | Room Temperature (25°C) | 538°C (1000°F) | 650°C (1200°F) |
|---|---|---|---|
| Yield Strength (0.2% offset, MPa) | ~1,035 | ~930 | ~760 – 820 |
| Ultimate Tensile Strength (MPa) | ~1,280 – 1,380 | ~1,110 | ~950 – 1,000 |
| Elongation (%) | 12 – 20 | ~18 | ~15 |
| Creep Rupture Strength (MPa, 1000h) | – | ~725 | ~690 |
| Fatigue Strength (HCF, MPa) | ~450 (10⁷ cycles) | ~380 | ~320 |
| Fracture Toughness (K_IC, MPa√m) | ~120 – 150 | ~110 – 130 | ~100 – 120 |
| Hardness (HRC) | 36 – 45 | 34 – 40 | 32 – 38 |
Corrosion resistance and oxidation resistance of Inconel 718
Inconel 718 offers excellent resistance to various corrosive environments, making it highly reliable in applications exposed to aggressive chemicals, moisture, and high-temperature oxidizing conditions.
Its corrosion resistance is primarily due to its high nickel (Ni) and chromium (Cr) content, as well as molybdenum (Mo) and niobium (Nb) for enhanced resistance to pitting and crevice corrosion.
| Environment | Performance Summary |
|---|---|
| Chloride‑Rich (e.g., Seawater) | Excellent resistance to pitting and crevice corrosion; suitable for marine and offshore use. |
| Acid Gases (H₂S) | Compliant with NACE MR0175/ISO 15156; resists sulfide stress cracking. |
| Acids (e.g., HNO₃, H₂SO₄) | Good resistance in mixed‑acid environments; moderate resistance in highly reducing acids. |
| Industrial Atmospheres | Stable in humid, polluted, and acidic conditions, including flue gases and refinery settings. |
| High‑Temperature Water/Steam | Suitable for nuclear and power‑generation systems; retains passivity under elevated pressure/temperature. |
Inconel 718 is frequently used in downhole oilfield tools, chemical reactors, fasteners, and heat exchangers where corrosion is a critical factor.
Oxidation Resistance
Inconel 718 performs well in oxidizing atmospheres up to ~980°C, although its mechanical strength limits practical service to ~650°C.
Protective Oxide Film: The alloy forms a dense Cr₂O₃ (chromia) layer that resists spalling and prevents further oxidation.
Thermal Cycling: Maintains surface integrity during repeated heating and cooling, making it suitable for jet engine components and turbine hardware.
Sulfidation: Exhibits good resistance to high-sulfur combustion environments compared to stainless steel, although less than some Mo-containing alloys.
Comparison of Inconel 718 with other materials
Inconel 718 vs other nickel-based superalloys
| Material | Temperature Capability (°C) | Strength | Weldability / Workability | Typical Applications |
|---|---|---|---|---|
| Inconel 718 | Up to ~700°C | High (due to γ', γ'') | Good weldability and machinability | Turbine disks, aerospace components, oil & gas |
| Inconel 625 | Up to ~980°C | Moderate | Excellent weldability | Corrosion resistance, chemical processing |
Summary: Inconel 718 offers a balanced combination of high strength and relatively good machinability, unlike some other high-temperature alloys that prioritize high-temperature strength at the expense of manufacturability.
Stainless steel and Inconel 718
| Material | Temperature Capability (°C) | Corrosion Resistance | Strength | Typical Applications |
|---|---|---|---|---|
| Inconel 718 | Up to ~700°C | Excellent (Oxidation, Corrosion) | Very High | High‑temperature aerospace, power generation |
| 316L Stainless Steel | Up to ~400°C | Good (Chloride Resistance) | Moderate | Chemical tanks, marine fittings |
| 17‑4 PH Stainless Steel | Up to ~480°C | Good | Moderate to High | Aerospace, pump shafts, valves |
Summary: Inconel 718 outperforms stainless steel in high-temperature and corrosive environments, making it the preferred choice when strength and oxidation resistance are critical.
Inconel 718 vs titanium alloy
| Material | Temperature Capability (°C) | Strength-to-Weight Ratio | Corrosion Resistance | Typical Applications |
|---|---|---|---|---|
| Inconel 718 | Up to ~700°C | Moderate | Excellent | High‑temperature components, turbine disks |
| Ti‑6Al‑4V | Up to ~400°C | Very High | Good | Aerospace structural parts, medical implants |
| Ti‑6242 | Up to ~540°C | High | Good | Jet engine compressor blades, structural parts |
Summary: Titanium alloys offer excellent strength-to-weight ratio and corrosion resistance at moderate temperatures, but nickel-chromium-iron alloy 718 remains superior for high-temperature applications where strength retention is crucial.
Applications of Inconel 718
INCONEL 718 alloy is widely used in critical applications requiring high strength and corrosion resistance:
Aerospace: Aircraft engine components, rocket engines, and spacecraft.
Gas turbines: Turbine discs, blades, and seals.
Nuclear reactors: Core components and reactor internal structures.
Oil and gas: Wellhead components, valves, and downhole tools.
Automotive: Turbocharger rotors and seals.
Inspection and packaging of inconel 718 Product
Testing Of inconel 718
Gnee Steel is renowned for its perfect dimensional accuracy. All products undergo rigorous testing before shipment. We perform both destructive and non-destructive testing on all products.
Eddy current testing
Hydrostatic pressure analysis
Pitting corrosion protection testing
Power generation industry
Material composition identification
Packing Of Inconel 718 Product
Gnee Steel uses the safest and most effective packaging methods for all types of cargo transportation. Our packaging methods include:
Wooden crates
Wooden pallets
Shrink wrap packaging
Cardboard boxes
Wooden crates
About Gnee Steel
Gnee Steel specializes in the production and sale of various nickel-based alloys, including Nickel 201, Nickel 202, Hastelloy C-276, Hastelloy C-22, Hastelloy B, Hastelloy C-4, Inconel Alloy 600, Inconel 625, Inconel 718, Inconel X-750, Incoloy Alloy 800, Incoloy 800H/HT, Incoloy 825, Monel Alloy 400, Monel K500, and high-temperature alloys. Gnee Steel's products are widely used in aerospace, chemical, electric power, automotive, and nuclear energy applications. We also offer customized alloy solutions tailored to customer needs. For alloy pricing inquiries or customized alloy solutions, please contact us for a quote at ss@gneesteel.com.
FAQ
Q: Is Inconel 718 hard to machine?
A: This nickel-based superalloy is a commonly used material in the aerospace industry, possessing excellent strength and heat resistance. However, these very characteristics make it extremely difficult to machine. Inconel 718 alloy is prone to rapid work hardening, leading to extremely high temperatures at the tool-workpiece interface, thus accelerating tool wear.
Q: What are the disadvantages of Inconel 718?
A: Disadvantages and Alternatives of Inconel 718
Although Inconel 718 possesses excellent mechanical properties and corrosion resistance, it also has some drawbacks: High cost: Due to its complex manufacturing process, Inconel 718 is expensive. Difficult to machine: Its high hardness makes material removal difficult and accelerates tool wear.
Q: What is the maximum operating temperature of Inconel 718?
A: Its performance is reliable for continuous service up to 650°C (1,200°F). For short periods (minutes to hours), it can withstand up to 800°C, but its strength decreases significantly above 650°C.
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