Inconel 718 (UNS N07718) Forgings — Age-Hardenable Nickel Superalloy for Gas Turbine Discs, Shafts & Casings
Shivam Forge manufactures forgings in Inconel 718 (UNS N07718) — the world's most widely used aerospace nickel superalloy, age-hardened through gamma-prime and gamma-double-prime precipitation to deliver high strength retained to approximately 700°C — for gas turbine engine compressor and turbine disc, shaft, and casing forgings. AMS specification support. Rajkot, India. Call +91-9265772827.
Inconel 718 solves a materials problem that few alloys can address simultaneously: it needs to deliver genuinely high structural strength, retain that strength at temperatures well beyond where standard steel and even most stainless grades have already begun to soften, and remain fabricable enough — weldable, machinable, formable — to be manufactured into the complex precision geometries gas turbine engine components require. 718 achieves this combination through precipitation (age) hardening, a heat treatment mechanism distinctly different from the solid-solution strengthening that alloys like Inconel 625 rely on: a solution heat treatment followed by a controlled two-step aging cycle precipitates fine, coherent gamma-double-prime (Ni3Nb, body-centered tetragonal) particles throughout the nickel-iron-chromium matrix, supplemented by a smaller volume fraction of gamma-prime (Ni3(Al,Ti)) phase, and it's this dense, uniformly distributed precipitate structure that gives 718 both its high room-temperature strength and its useful strength retention up to roughly 700°C — a temperature range that covers a meaningful portion of a gas turbine engine's compressor and early turbine section operating environment. This specific combination of high strength, elevated-temperature capability, and good fabricability — a combination genuinely difficult to find together in a single alloy — is exactly why Inconel 718 became, and remains, the single most widely used superalloy across the global aerospace gas turbine engine industry, specified into compressor and turbine disc forgings, shafts, and casing components across virtually every major commercial and military engine programme.
Forged 718 disc blanks for gas turbine compressor and hot-section-adjacent turbine stages, where the combination of high strength and elevated-temperature retention that 718's precipitation-hardened microstructure delivers is required.
Forged 718 shaft components transmitting torque between turbine and compressor sections, benefiting from the alloy's high strength-to-weight ratio and temperature capability.
Forged 718 casing and structural component blanks for gas turbine engine sections requiring both structural strength and elevated-temperature dimensional stability.
Forged 718 fastener blanks for high-temperature, high-strength bolting applications common in gas turbine casings and other extreme-service mechanical joints exceeding standard alloy steel fastener capability.
Solution heat treatment followed by controlled two-step aging cycle, precipitating the gamma-double-prime and gamma-prime phases that develop 718's characteristic high strength and elevated-temperature performance, per applicable AMS or customer-specified cycle.
Forgings supplied to AMS (Aerospace Material Specification) chemistry and mechanical property requirements where aerospace programme specification demands, including grain size and mechanical property verification per AMS-specified test methods.
Controlled forging practice and heat treatment managing grain size and delta phase (Ni3Nb, orthorhombic) distribution, both of which directly affect fatigue life and mechanical performance in rotating disc and shaft applications.
Positive material identification via handheld XRF spectrometry, combined with full chemical composition and mechanical property certification per EN 10204 3.1/3.2, with 3.2 third-party witnessed certification available for aerospace documentation requirements.
Gas turbine engines push structural materials to a genuinely difficult combination of requirements simultaneously: components have to be strong enough to survive substantial centrifugal and mechanical loading, they have to retain that strength at temperatures well beyond where conventional structural alloys have already begun losing capability, and they have to be manufacturable into precise, often geometrically complex shapes through forging, machining, and in many cases welding. Very few alloy systems can satisfy all three demands at once, which is precisely the gap Inconel 718 was engineered to fill, and why it has become the dominant single material specification across the aerospace gas turbine engine industry.
The metallurgical mechanism underlying 718's capability is precipitation hardening, and it's worth understanding in some detail because it directly shapes how the alloy must be processed. A solution heat treatment first dissolves the alloying elements into a uniform nickel-iron-chromium matrix, and a subsequent controlled two-step aging cycle then precipitates extremely fine, coherent particles throughout that matrix — primarily gamma-double-prime (Ni3Nb), a metastable body-centered-tetragonal phase that provides the majority of 718's strengthening effect, supplemented by a smaller fraction of gamma-prime (Ni3(Al,Ti)). These fine precipitates impede dislocation movement through the crystal lattice, which is the fundamental mechanism behind the alloy's high strength, and because the precipitate structure remains stable at elevated temperature (up to a practical limit around 700°C, beyond which the gamma-double-prime phase begins transforming to the less desirable, incoherent delta phase), 718 retains meaningful strength across a genuinely useful portion of a gas turbine's operating temperature range.
Getting this heat treatment right — accurate solution temperature control, correctly timed aging cycles, and forging practice that develops appropriate grain size ahead of heat treatment — is not a minor manufacturing detail but the entire basis of 718's value proposition as a material. Grain size and delta phase distribution both influence fatigue performance directly, which matters enormously in rotating disc and shaft applications where blade root attachment slots and other geometric features concentrate cyclic stress. This is why aerospace programmes specify 718 forgings against detailed AMS chemistry, heat treatment, and mechanical property requirements rather than treating the alloy as a commodity material — the manufacturing process genuinely determines whether the alloy delivers on its designed performance.
For gas turbine engine OEMs and aerospace Tier 1 suppliers sourcing forged Inconel 718 disc, shaft, or casing components, Shivam Forge manufactures with AMS specification support and full material traceability. Contact our engineering team at +91-9265772827 or sales@shivamforge.com with your drawing and specification for a manufacturability review and quotation.
718 requires a solution heat treatment followed by a controlled two-step aging cycle, precipitating fine gamma-double-prime (Ni3Nb) and gamma-prime (Ni3(Al,Ti)) phases throughout the matrix. This precipitation-hardening mechanism is what develops 718's high strength and elevated-temperature performance, unlike solid-solution alloys such as Inconel 625, which don't require this multi-step aging cycle.
718 retains useful strength up to approximately 700°C, which covers a meaningful portion of a gas turbine engine's compressor and early turbine section operating environment. Beyond this range, other superalloys with different strengthening mechanisms are typically specified instead.
Yes. Forgings can be supplied to AMS chemistry and mechanical property requirements including solution and double-age heat treatment per AMS-specified cycles, with grain size and mechanical property verification and full documentation for aerospace programme quality requirements.
Grain size directly affects fatigue life and mechanical performance in rotating disc and shaft applications — finer, more uniform grain structure generally improves fatigue resistance at the stress-concentrated locations rotating components experience, such as blade root attachment slots on disc forgings, making controlled forging practice and heat treatment important to consistent component performance.
718 is age-hardenable via gamma-double-prime and gamma-prime precipitation, delivering significantly higher strength retained at elevated temperature, which is why it dominates aerospace gas turbine disc and shaft applications where high-temperature structural strength is the design driver. Inconel 625 is solid-solution strengthened, without an age-hardening step, prioritizing broad-spectrum corrosion resistance and weldability for subsea, downhole, and chemical processing applications instead.
Why Choose Shivam Forge
Shivam Forge delivers precision hot-forged components from our integrated Shapar, Rajkot facility — covering forging, CNC machining, heat treatment, and quality inspection under one roof.
