Introduction

Inconel 718 Alloy (UNS N07718 / W.Nr. 2.4668) is a precipitation-hardenable nickel-chromium superalloy containing 50–55% nickel, 17–21% chromium, 4.75–5.50% niobium, and 2.80–3.30% molybdenum, strengthened by gamma double-prime (Ni₃Nb) and gamma-prime (Ni₃(Al,Ti)) precipitates during aging heat treatment. This high strength Inconel 718 delivers exceptional creep resistant nickel alloy performance at elevated temperatures (up to 1300°F / 700°C), excellent fatigue resistance, and good oxidation resistance up to 1800°F (980°C), maintaining mechanical properties from cryogenic temperatures to long-term service at 1200°F (650°C). Developed for aircraft engine components, this high temperature nickel alloy is the preferred material for aerospace, gas turbine, jet engine, power generation, oil and gas, nuclear industry, high temperature fasteners, and cryogenic applications. Available in Inconel 718 plate, sheet, seamless pipe, tube, bar, round bar, rod, wire, forgings, fasteners, flanges, and fittings, in hot rolled, cold rolled, solution annealed, and age hardened conditions.

Chemical components（%）

Mechanical properties

Physical properties

Inconel 718 Nickel-Based Superalloy Available Products and Standard

1. GB/T 14992 (Superalloys – Classification and Specifications)

Type: Round Bar / Sheet / Plate / Strip / Wire / Tube / Forgings

Size Range:

• Inconel 718 Wire: 0.1 – 15.0 mm dia

• Inconel 718 Strip: 0.05 – 5.0 mm thick × 5 – 500 mm wide

• Inconel 718 Round Bar: 8 – 355 mm dia

• Inconel 718 Sheet / Plate: 0.5 – 180 mm thick

• Inconel 718 Seamless Tube: Custom sizes available

Surface: Annealed, Bright, Pickled, Ground

Testing: Chemical analysis, mechanical test (tensile strength, yield strength, elongation), hardness test, high-temperature stress rupture test, fatigue test, dimensional inspection

2. ASTM B637 (Standard Specification for Precipitation Hardening Nickel Alloy Bar, Rod, Wire, and Forgings)

Grade: UNS N07718 / Inconel 718 / GH4169

Type: Round Bar / Rod / Wire / Forging / Ring

Size Range:

• Inconel 718 Round Bar: 8 – 355 mm dia (hot rolled or cold drawn)

• Inconel 718 Wire: 0.1 – 15.0 mm dia (coils or straight)

• Inconel 718 Forging / Ring: Custom sizes available

Surface: Annealed, Pickled, Ground, Turned, Bright

Testing: Chemical analysis, mechanical test (tensile, yield, elongation), hardness test, stress rupture test, ultrasonic test, dimensional inspectio

Applications

1. Aerospace & Aircraft Engine

• For aircraft engine components including turbine discs, compressor blades, and casings, Inconel 718 for aerospace delivers high temperature strength and creep resistant performance up to 1300°F (700°C). Developed in the early 1960s, Inconel 718 remains the material of choice for the majority of aircraft engine components with service temperatures below 1200°F (650°C).

• For jet engine hot section parts, ducting systems, and exhaust system components, Alloy 718 withstands extreme thermal cycling and maintains mechanical integrity. In fact, 50% of the materials used in aircraft and rocket engines are nickel-based superalloys. The nickel based superalloy 718 accounts for more than one third of the nickel-based superalloy used in aerospace engines.

• For aerospace fasteners including bolts and T-head screws, Inconel 718 fasteners are specified with classification 1275 MPa/650°C, primarily stressed in shearing force. The material's load-bearing capacity makes it ideal for turbine discs and rocket motor cases.

2. Gas Turbine & Power Generation

• For gas turbine components including combustor liners, transition ducts, and turbine shrouds, High temperature Inconel 718 resists oxidation and thermal fatigue, allowing service intervals of several thousand hours without significant property degradation.

• For power generation equipment and industrial gas turbines, Alloy 718 is heat treated to give maximum strength and high creep resistance with typical hardness values exceeding HRC 42.

• For turbine discs and high-speed rotating components, age hardenable nickel alloy 718 maintains its mechanical properties at elevated temperatures, ensuring reliable performance under extreme centrifugal loads.

3. Oil & Gas / Nuclear Industry

• For oil and gas downhole tools, wellhead components, and blowout preventer (BOP) parts, Inconel 718 for oil and gas provides exceptional fatigue resistant performance and corrosion resistance in sour service environments.

• For nuclear industry applications including reactor components, pumps, and turbo pump seals, UNS N07718 alloy offers the high performance superalloy characteristics required for demanding nuclear environments.

4. Cryogenic & High Temperature Fasteners

• For cryogenic applications down to -252°C (-423°F), Inconel 718 retains excellent mechanical properties and ductility, making it suitable for liquefied gas handling, spacecraft, and space shuttle components.

• For high temperature fasteners including bolts, nuts, and studs in aerospace and gas turbine assemblies, Inconel 718 fasteners offer the combination of high strength, creep resistance, and oxidation resistance required for critical bolted joints.

5. Rocket Motors & Spacecraft

• For rocket motor cases, thrust chambers, and nozzle components, Inconel 718 superalloy provides the high strength-to-weight ratio and thermal stability required for space applications.

• For spacecraft structural components and propulsion systems, Alloy 718 maintains integrity across the extreme temperature range from cryogenic to elevated service conditions.

6. General Industrial & Tooling Applications

• For tooling and high-performance industrial equipment, Inconel 718 bar and round bar are machined into precision components requiring both strength and corrosion resistance.

• For gas turbine and jet engine components, Inconel 718 plate and sheet are fabricated into complex shapes with excellent weldability, as the alloy may be welded in either the annealed or precipitation hardened (aged) condition.

FAQ – Inconel 718 Alloy

Q: What is the difference between Inconel 718 and Inconel 625?

A: Inconel 718 alloy is a precipitation-hardenable nickel-chromium alloy with niobium and molybdenum, designed for high strength at elevated temperatures—offering yield strength up to 1,035 MPa and fatigue strength of 620 MPa. Inconel 625 is a solid-solution strengthened alloy with higher molybdenum content, offering superior corrosion resistance in chlorides and acids. A simple way to think about it: 625 is tougher against corrosion, while 718 can take more stress. Choose 718 for high-temperature strength and creep resistance; choose 625 for corrosion resistance in aggressive environments.

Q: What is the maximum operating temperature for Inconel 718?

A: Inconel 718 alloy is designed for long-term service up to 1200°F (650°C), with excellent creep-rupture strength at temperatures up to 1300°F (700°C). It offers oxidation resistance up to 1800°F (980°C). The alloy was developed specifically for aircraft engine components with service temperatures below 1200°F (650°C). For continuous service above 650°C, other superalloys such as Waspaloy or Rene 41 may be considered.

Q: Can Inconel 718 be welded, and does it require post-weld heat treatment?

A: Yes, Inconel 718 sheet and pipe can be welded using TIG, MIG, and other standard processes. The alloy can be welded in either the annealed or precipitation hardened (aged) condition. However, welding can cause Laves phase formation in the as-welded condition, leading to lower strength. Post-weld aging treatment at approximately 780°C is typically sufficient to strengthen the welds, and post-weld solution treatment is generally not necessary for strength recovery. Direct aging and solutionizing treatments (980STA, 1080STA) can improve corrosion resistance and mechanical behavior of the welds.

Q: What industries commonly use Inconel 718?

A: Aerospace (aircraft engines, turbine discs, jet engine components, rocket motors), gas turbine power generation (combustor liners, transition ducts), oil and gas (downhole tools, wellhead components, BOP parts), nuclear industry (reactor components, pumps, seals), high temperature fasteners (aerospace bolts, studs), cryogenic applications (spacecraft, liquefied gas handling), and tooling for high-performance manufacturing. This high performance superalloy is the material of choice where strength, creep resistance, and fatigue performance are critical.

We are a trusted Inconel 718 Supplier and Inconel 718 Manufacturer, China-based, serving aerospace, gas turbine, oil and gas, nuclear industry, and power generation sectors worldwide. All products comply with ASTM B670 / ASTM B637 / ASME SB637 with EN 10204 3.1 mill certificates, PMI verification, and dimensional inspection reports. We offer Inconel 718 plate, sheet, seamless pipe, tube, bar, round bar, rod, wire, forgings, fasteners, flanges, and fittings in custom sizes, with cut‑to‑size, precision machining, and age hardening services. Contact us at info@monokj.com for size chart, pricing, or custom requirements.