AMS 5662 — Aerospace Material Specification for Inconel 718 Bar and Forging Stock, Layering Certified Melt Practice and Testing Beyond Commercial 718
Shivam Forge manufactures forgings to SAE AMS 5662 — the aerospace material specification governing Inconel 718 (UNS N07718) bar and forging stock, adding certified melt practice, grain size control, and mechanical testing requirements on top of the same age-hardenable nickel-iron-chromium chemistry used in commercial 718 applications. Gas turbine disc, shaft, and flight-critical fastener forgings. Rajkot, India. Call +91-9265772827.
AMS 5662 governs the same fundamental Inconel 718 alloy chemistry this site's Inconel 718 page covers — the nickel-iron-chromium composition age-hardened through gamma-double-prime and gamma-prime precipitation to deliver high strength retained to roughly 700°C — but, in the same relationship this site's SAE AMS 6414 page describes for 4340 alloy steel, AMS 5662 is not simply a relabeled commercial designation. It is an aerospace material specification that layers a materially more demanding set of melt practice, grain size, and mechanical testing requirements on top of 718's base chemistry, because a turbine disc rotating at high speed under sustained centrifugal load for tens of thousands of flight hours carries a failure consequence that a commercial 718 valve component or industrial fastener does not. Where commercial 718 supply may be produced by vacuum induction melting (VIM) alone, AMS 5662 typically requires double or triple melt practice — VIM plus vacuum arc remelt (VAR), or VIM-VAR-VAR — specifically to reduce non-metallic inclusion content, minimize elemental segregation (particularly niobium segregation, which 718 is genuinely prone to and which directly affects the uniformity of gamma-double-prime precipitation during aging), and produce the finer, more consistent grain structure rotating disc applications require for fatigue life. AMS 5662 correspondingly imposes tighter mechanical property minimums verified per specified test locations within the forging, mandatory ultrasonic inspection to aerospace acceptance criteria, and grain size verification per ASTM E112 to a specified maximum grain size — none of which commercial 718 bar or forging supply is obligated to demonstrate. The result, exactly as with AMS 6414 relative to commercial 4340, is a genuine, justified cost and lead-time premium reflecting demonstrably lower defect probability and tighter, more consistent mechanical properties in a rotating, flight-critical application where an undetected melt-related defect can propagate to catastrophic disc failure.
Forged AMS 5662 disc blanks for compressor and turbine rotating stages, where certified melt practice and grain size control directly address the fatigue-critical, high-cycle centrifugal loading disc applications experience.
Forged AMS 5662 shaft and spacer component blanks transmitting torque and maintaining rotor stack alignment, benefiting from the specification's tighter mechanical property minimums and internal soundness verification.
Forged AMS 5662 bar stock for high-strength, high-temperature fasteners and pins in flight-critical engine assemblies requiring 718's strength-temperature combination with aerospace-grade melt cleanliness.
AMS 5662-certified bar and forging blanks supplied with full heat and lot traceability for aerospace forging shops and machine shops requiring verified aerospace-grade raw material for downstream flight-critical part production.
Sourcing of AMS 5662-compliant bar stock produced to double or triple vacuum melt practice, specifically reducing non-metallic inclusion content and niobium segregation relative to standard commercial single-melt or VIM-only 718 production.
Grain size evaluation per ASTM E112 confirming compliance with AMS 5662's specified maximum grain size, directly relevant to fatigue life in rotating disc applications where coarse or non-uniform grain structure degrades performance.
Ultrasonic testing for internal defects evaluated against AMS acceptance criteria meaningfully tighter than typical commercial 718 inspection practice, verifying the melt cleanliness the specification's melt practice requirement is intended to deliver.
Complete chemical composition, mechanical property, and melt practice certification traceable to specific heat and forging lot, supporting the airworthiness documentation aerospace primes and their supply chain require.
AMS 5662 covers Inconel 718, the world's most widely used aerospace nickel superalloy, but treating the specification as merely a certified relabeling of commercial 718 understates what it actually requires. The base age-hardening chemistry — the nickel-iron-chromium composition that develops high strength through gamma-double-prime and gamma-prime precipitation during a solution-and-double-age heat treatment cycle — is genuinely the same alloy commercial 718 specifications cover. What AMS 5662 changes is the melt practice, internal cleanliness verification, grain size control, and documentation surrounding that chemistry, reflecting the simple fact that a gas turbine disc rotating under sustained centrifugal load for tens of thousands of flight hours carries a failure consequence a commercial 718 component in a less demanding application does not.
The melt practice distinction is where AMS 5662's requirements become most concrete, and it connects directly to a genuine metallurgical vulnerability specific to 718: niobium, the element responsible for the gamma-double-prime phase that gives 718 most of its strength, is prone to segregating unevenly during solidification if melt practice isn't tightly controlled, producing regions of the material with inconsistent niobium content and, downstream, inconsistent precipitation hardening response during aging. Double or triple vacuum melt practice — vacuum induction melting followed by one or two vacuum arc remelt operations — specifically addresses this segregation risk, along with reducing non-metallic inclusion content, to a degree standard commercial single-melt or VIM-only practice does not reliably achieve. In a rotating disc application where uniform mechanical properties through the entire component genuinely matter, this melt practice difference is not a cosmetic upgrade but a direct driver of whether the material performs consistently under sustained cyclic load.
This same logic extends through AMS 5662's testing and documentation requirements: grain size verification per ASTM E112 against a specified maximum, since coarse or non-uniform grain structure degrades fatigue performance specifically in the kind of rotating disc application 718 is so widely used for, and mandatory ultrasonic inspection evaluated against acceptance criteria meaningfully tighter than typical commercial practice, confirming that the melt practice requirement has actually delivered the internal cleanliness it's intended to produce. None of this is bureaucratic overhead — each requirement targets a specific failure mode that matters disproportionately in a flight-critical rotating component, which is why aerospace programmes specify AMS 5662 by name and require documented proof of compliance rather than accepting an unverified assurance that the material is basically equivalent to commercial-grade 718.
For gas turbine engine OEMs, aerospace Tier 1 suppliers, and forging shops requiring AMS 5662-compliant Inconel 718 components, Shivam Forge sources certified melt-practice-compliant material and provides full mechanical, grain size, ultrasonic, and traceability documentation matched to your program's airworthiness requirements. Contact our engineering team at +91-9265772827 or sales@shivamforge.com with your drawing and AMS specification callout for a manufacturability review and quotation.
AMS 5662 governs the same base 718 chemistry as commercial specifications but adds aerospace-specific requirements: certified double or triple vacuum melt practice (typically VIM-VAR or VIM-VAR-VAR) to reduce non-metallic inclusions and niobium segregation, tighter mechanical property minimums verified at specified locations, mandatory grain size verification per ASTM E112, and mandatory ultrasonic inspection to stricter acceptance criteria. These additions specifically address the fatigue-critical, rotating-component nature of gas turbine disc and shaft applications.
718's characteristic strength comes from gamma-double-prime (Ni3Nb) precipitation during aging, and niobium is genuinely prone to segregating unevenly during solidification if melt practice isn't tightly controlled. Uneven niobium distribution produces inconsistent gamma-double-prime precipitation and correspondingly inconsistent mechanical properties through the component, which is precisely why AMS 5662's melt practice requirements target this specific segregation risk.
Yes, and the premium is genuine rather than a paperwork formality — it reflects the real cost of double or triple vacuum melt practice, mandatory grain size and ultrasonic testing to tighter acceptance criteria, and full traceability documentation, all of which measurably reduce defect probability and deliver more consistent mechanical properties than commercial-grade 718 of identical nominal chemistry.
No. Commercial 718, even from a reputable mill, is not produced or tested to AMS 5662's melt practice, grain size, and traceability requirements, and aerospace primes and airworthiness regulatory frameworks require verified AMS-compliant material with matching certification for rotating and other flight-critical parts.
Yes. We supply AMS 5662-compliant forgings and bar stock with full chemical composition, mechanical property, melt practice, grain size, and ultrasonic test certification traceable to specific heat and forging lot, supporting the airworthiness documentation your aerospace program requires.
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.
