AMS 5663 - Inconel 718 (UNS N07718) Bars, Forgings & Rings (Precipitation Hardened)
What is AMS 5663?
AMS 5663 is the SAE International aerospace material specification for Inconel 718 (UNS N07718) bars, forgings, and rings in the precipitation hardened (double aged) condition.
Minimum mechanical properties: tensile strength 185 ksi (1276 MPa), yield strength 150 ksi (1034 MPa), elongation 12%, reduction in area 15%. Precipitation hardening cycle: 1325°F (718°C) / 8 hours → furnace cool at 100°F/hr to 1150°F (621°C) / 8 hours → air cool. VIM+VAR double-melt practice is required.
AMS 5663 is the final, service-ready delivery condition for Inconel 718 rotating hardware – turbine discs, compressor discs, engine shafts, and turbine rings delivered at full design strength without further heat treatment.
Parts requiring complex machining are typically procured in the solution treated condition per AMS 5662, machined, and then precipitation heat treated to AMS 5663 requirements before final delivery.
AMS 5663 Available Forms and Stocked Sizes
AMS 5663 covers Inconel 718 in long and forged product forms. The SAE/AMS product form definitions are:
Solid section of uniform cross-section (round, rectangular, square, or hexagonal); length significantly greater than cross-section dimension; supplied hot-rolled or cold-finished in random or cut lengths
A part or starting stock shaped by controlled deformation of a heated metal billet under compressive force (hammering or pressing); forgings exhibit improved grain flow and mechanical properties compared to bar stock of equivalent cross-section
A toroidal (donut-shaped) forging produced by a ring-rolling process or open-die forging; used for turbine containment rings, flanges, casings, and structural ring components
Fighter Jet Metals supplies Inconel 718 per AMS 5663 in round bar from 0.125″ to 14.00″ diameter, flat bar in various cross-sections, forging stock and billets to customer requirement, and rolled or forged ring forms to customer drawings.
All material is supplied in the precipitation hardened condition with full certified mill test reports (CMTR) and certificates of conformance.
Applications of AMS 5663
Aerospace & Gas Turbine Applications
- Jet engine turbine discs and compressor discs delivered in the fully precipitation hardened condition at final design strength, ready for NDE and assembly
- Engine shafts and stub shafts requiring final tensile and fatigue properties at delivery – no post-machining heat treatment required by the end user
- Turbine rings, retention rings, and ring forgings for hot-section containment and structural support in engine assemblies
- High-strength engine bolts, studs, and fasteners where full precipitation hardened strength is required in the fastener
- Aerospace structural brackets and fittings requiring Inconel 718 at full precipitation hardened strength
- Launch vehicle and spacecraft structural components where high strength-to-weight and dimensional stability are critical
Oil & Gas and Industrial Applications
- High-pressure wellhead, christmas tree, and downhole tool components requiring Inconel 718 at full precipitation hardened strength for H2S service
- Pump shafts and compressor impellers for subsea processing equipment delivered at final hardened properties
- Nuclear power plant fastener and structural hardware requiring combined strength and corrosion resistance at service
Defense Applications
- Military aircraft engine components requiring delivery at final heat-treated strength for accelerated assembly schedules
- Gas turbine components for naval and land-based propulsion systems at fully precipitation hardened properties
- Defense hardware requiring full OEM certification to precipitation hardened condition specifications (Boeing BMS, GE B50, MTU MTS, Pratt & Whitney PWA-S-5663, Airbus ABS5443)
Chemical Composition - AMS 5663
The following chemical composition limits apply to Inconel 718 (UNS N07718) per AMS 5663.
The composition is identical to AMS 5662 – AMS 5663 specifies the same alloy in the precipitation hardened condition:
| Element | Symbol | Minimum % | Maximum % |
|---|---|---|---|
| Nickel + Cobalt | Ni + Co | 50.0 | 55.0 |
| Chromium | Cr | 17.0 | 21.0 |
| Iron | Fe | Balance | - |
| Niobium + Tantalum | Nb+Ta | 4.75 | 5.50 |
| Molybdenum | Mo | 2.80 | 3.30 |
| Cobalt | Co | - | 1.00 |
| Titanium | Ti | 0.65 | 1.15 |
| Aluminum | Al | 0.20 | 0.80 |
| Carbon | C | - | 0.08 |
| Manganese | Mn | - | 0.35 |
| Silicon | Si | - | 0.35 |
| Phosphorus | P | - | 0.015 |
| Sulfur | S | - | 0.015 |
| Boron | B | - | 0.006 |
| Copper | Cu | - | 0.30 |
Niobium + Tantalum (4.75–5.50%) is the most critical alloying element in Inconel 718. Niobium forms the Ni₃Nb gamma-double-prime (γ”) phase during the precipitation hardening cycle – this is the primary hardening precipitate that produces the exceptional 185 ksi tensile strength required by AMS 5663.
The two-stage aging cycle at 1325°F (718°C) and 1150°F (621°C) controls the size, distribution, and volume fraction of the γ” phase to achieve consistent, reproducible mechanical properties in every heat and product cross-section.
Aluminum (0.20–0.80%) and titanium (0.65–1.15%) form the secondary gamma-prime (γ’) phase alongside the dominant γ”, contributing additional precipitation hardening response. Chromium (17.0–21.0%) provides oxidation and corrosion resistance at elevated service temperatures.
Molybdenum (2.80–3.30%) contributes solid-solution strengthening to the nickel-iron matrix in both the aged and un-aged condition.
Mechanical Properties - AMS 5663
Minimum mechanical properties required by AMS 5663 for Inconel 718 bars, forgings, and rings in the precipitation hardened (double aged) condition:
| Property | Imperial | Metric |
|---|---|---|
| Tensile Strength (min) | 185,000 psi (185 ksi) | 1276 MPa |
| Yield Strength, 0.2% offset (min) | 150,000 psi (150 ksi) | 1034 MPa |
| Elongation in 2 in. or 4D (min) | 12% | 12% |
| Reduction in Area (min) | 15% | 15% |
Elevated Temperature Properties - AMS 5663
The following representative typical elevated temperature properties are for Inconel 718 in the precipitation hardened condition – the service condition specified by AMS 5663.
Values are from published literature (Special Metals Technical Bulletin):
| Temperature | Tensile Strength (typical) | Yield Strength (typical) | Elongation (typical) |
|---|---|---|---|
| Room Temp (70°F / 21°C) | 200 ksi (1379 MPa) | 170 ksi (1172 MPa) | 20% |
| 400°F (204°C) | 190 ksi (1310 MPa) | 162 ksi (1117 MPa) | 19% |
| 800°F (427°C) | 183 ksi (1262 MPa) | 158 ksi (1089 MPa) | 18% |
| 1000°F (538°C) | 181 ksi (1248 MPa) | 156 ksi (1075 MPa) | 17% |
| 1200°F (649°C) | 170 ksi (1172 MPa) | 148 ksi (1020 MPa) | 15% |
| 1300°F (704°C) | 155 ksi (1069 MPa) | 135 ksi (931 MPa) | 14% |
Physical Properties - AMS 5663
| Property | Value (Imperial) | Value (Metric) |
|---|---|---|
| Density | 0.296 lb/in³ | 8.19 g/cm³ |
| Melting Range | 2300°F–2437°F | 1260°C–1336°C |
| Modulus of Elasticity | 29.0 × 10⁶ psi | 200 GPa |
| Thermal Conductivity | 6.5 BTU/(hr·ft·°F) | 11.2 W/(m·K) |
| Thermal Conductivity (1000°F) | 9.8 BTU/(hr·ft·°F) | 17.0 W/(m·K) |
| Coefficient of Thermal Expansion | 7.2 × 10⁻⁶ /°F | 13.0 × 10⁻⁶ /°C |
| Specific Heat | 0.104 BTU/(lb·°F) | 435 J/(kg·K) |
| Max Service Temperature (Mechanical Load) | 1300°F | 704°C |
| Max Service Temperature (Oxidation Resistance) | 1800°F | 982°C |
| Melt Practice | VIM + VAR (double melt) | - |
AMS 5662 vs AMS 5663 vs AMS 5664 - Which Specification Do You Need?
All three are SAE AMS specifications for Inconel 718 (UNS N07718) in bar and forging product forms, but they differ in condition, heat treatment, and intended use:
| Feature | AMS 5662 | AMS 5663 | AMS 5664 |
|---|---|---|---|
| Alloy | Inconel 718 (UNS N07718) | Inconel 718 (UNS N07718) | Inconel 718 (UNS N07718) |
| Product Forms | Bars, Forgings, Rings | Bars, Forgings, Rings | Bars, Forgings |
| Condition | Solution Treated | Precipitation Hardened (Double Aged) | Cold Drawn |
| Tensile Min | 150 ksi (1034 MPa) | 185 ksi (1276 MPa) | See current revision |
| Yield Strength (min) | 75 ksi (517 MPa) | 150 ksi (1034 MPa) | See current revision |
| Elongation (min) | 30% | 12% | See current revision |
| Primary Use | Rough machining stock; starting material to be heat treated to AMS 5663 after machining | Final components at full design strength — parts delivered in service-ready condition | Cold-drawn bars requiring tighter diameter tolerances and controlled surface condition |
| Key Advantage | Maximum machinability and ductility for complex machining operations | Maximum tensile, yield, and fatigue strength for service in rotating engine hardware | Tighter dimensional tolerances and better surface finish than hot-finished bar |
Specify AMS 5663 when the part must be delivered at full precipitation hardened mechanical properties without further heat treatment – typically final machined parts delivered as-hardened to the OEM or as-machined components for direct assembly.
Specify AMS 5662 when procuring bar stock for machining before heat treatment.
Specify AMS 5664 for cold-drawn bar applications requiring tight diameter tolerances.
Approved Mill Producers
Fighter Jet Metals sources AMS 5663 Inconel 718 bars, forgings, and ring stock from AS9100D-certified mill producers.
All material is supplied with full certified mill test reports (CMTR), heat/lot numbers, chemical analysis reports, and mechanical test certifications traceable to the originating mill heat and melt practice (VIM+VAR confirmed on CMTR). The CMTR includes hardness test results confirming the precipitation hardened condition per AMS 5663 requirements.
AMS 5663 Machining Guidelines
Machining Inconel 718 in the precipitation hardened condition per AMS 5663 is significantly more demanding than machining in the solution treated condition per AMS 5662.
The precipitation hardened condition has:
- Higher hardness: Approximately 40+ HRC in the precipitation hardened condition, compared to ~35 HRC solution treated – tooling life is reduced and cutting forces are higher
- Reduced ductility: The lower elongation (12% vs 30%) means less plastic deformation before fracture – the material is more brittle under cutting forces, increasing the risk of chipping at sharp features
- Aggressive work-hardening: Even the hardened material work-hardens further at the cutting surface if cutting conditions are incorrect
When machining AMS 5663 precipitation hardened material is unavoidable (e.g., minor finishing after heat treatment):
- Cutting speeds: Reduce to 40–80 SFM for carbide tooling (significantly slower than solution treated)
- Sharp tooling mandatory: Use premium PVD TiAlN-coated carbide; dull tooling causes rapid work-hardening and built-up edge
- Feed rates: Maintain positive, aggressive feeds – do not dwell in cut; use climb milling where possible
- Coolant: High-pressure flood coolant required; sulfurized cutting oils for turning
- Minimize stock removal: Reserve major machining operations for the solution treated (AMS 5662) condition before heat treatment. Only minor finishing, grinding, and close-tolerance operations should be performed on precipitation hardened AMS 5663 material
Weldability of AMS 5663
Welding of Inconel 718 in the precipitation hardened condition (AMS 5663) requires more care than welding the solution treated condition (AMS 5662) due to increased sensitivity to heat-affected zone (HAZ) cracking:
- TIG (GTAW): Preferred process for repairs and joining; argon or helium-argon shielding; matched Inconel 718 filler (ERNiCrMo-1) recommended
- HAZ cracking risk: The precipitation hardened condition is more susceptible to strain-age cracking in the heat-affected zone than solution treated material – welding should be performed on AMS 5662 (solution treated) where possible, with post-weld heat treatment to restore AMS 5663 properties
- Pre-weld condition preferred: SAE AMS and Boeing best practice is to weld in the solution treated (AMS 5662) condition, then precipitation heat treat the assembly to AMS 5663 properties – this avoids HAZ cracking entirely
- Post-weld heat treatment: Full solution treat + precipitation age per AMS 2774 must be performed after any structural weld to restore the AMS 5663 mechanical property requirements in the weld zone and HAZ
- Inconel 718’s advantage: Despite the higher precipitation hardened hardness, Inconel 718’s γ” slow precipitation kinetics still make it one of the most weldable precipitation-hardened nickel superalloys – significantly better than Waspaloy, Rene 41, and A286 in terms of HAZ cracking resistance
Melt Practice - AMS 5663
To produce Inconel 718 per AMS 5663, double melting is required.
The primary melt is performed by Vacuum Induction Melting (VIM), which establishes precise chemistry control in a vacuum environment, removing dissolved oxygen and nitrogen.
The primary melt ingot is then remelted using Vacuum Arc Remelting (VAR). This VIM+VAR double-melt process eliminates segregation and macro-inclusions that are unacceptable in rotating aerospace hardware, and produces a clean, homogeneous ingot with uniform chemistry and mechanical properties from center to surface.
For the most demanding rotating components (engine discs, turbine shafts), some procurement standards require triple-melt processing (VIM + ESR + VAR) to further improve cleanliness and fatigue life.
Always confirm the melt practice on the certified mill test report before procurement.
AMS 5663 Cross-Reference Specifications
SHEET & PLATE
Inconel 718 flat-rolled specifications in solution annealed and precipitation hardened conditions – different product form counterparts to AMS 5663.
BARS & FORGINGS
Inconel 718 bars, forgings, and rings in the solution treated and cold drawn conditions – complementary specifications to AMS 5663.
BOEING SPECIFICATIONS
Boeing material and process specifications for Inconel 718 bars and forgings in the precipitation hardened condition and heat treatment process specifications applicable to AMS 5663 material.
GE AVIATION
GE Aviation engine material specifications for Inconel 718 bars and forgings in high-temperature rotating turbine and compressor hardware.
MTU AERO ENGINES
MTU Aero Engines specification for Inconel 718 bars and forgings in the precipitation hardened (heat-treated) condition for gas turbine engine components.
PRATT & WHITNEY PWA
Pratt & Whitney engine material specification for Inconel 718 bars and forgings in the heat-treated and aged condition directly equivalent to AMS 5663.
AIRBUS
Airbus material specification for Inconel 718 bars, forgings, and rings covering both solution treated and precipitation hardened conditions for Airbus commercial aerospace manufacturing.
SNECMA / SAFRAN
Safran / Snecma engine material specification for Inconel 718 bars and forgings in French-designed turbofan engine rotating components.
ISRAEL AEROSPACE INDUSTRIES
Israel Aerospace Industries specification for Inconel 718 in defense and aerospace programs requiring strict chemical, mechanical, and traceability compliance.
Trade Names and Equivalent Designations
Inconel 718 per AMS 5663 is known by many trade names and equivalent designations across different standards systems:
| Designation | System | Notes |
|---|---|---|
| Inconel 718 | Trade name | Special Metals / Precision Castparts registered trademark - most widely used commercial name |
| Nickel 718 / Nickel Alloy 718 | Common name | Generic material designation used in procurement |
| ASTM B637 | ASTM specification | Rod, bar, and wire per ASTM system |
| UNS N07718 | UNS (Unified Numbering System) | Standard material identifier in North America |
| DIN 2.4668 / W.Nr. 2.4668 | Werkstoff Nr. (German) | European material number designation |
| NiCr19Fe19Nb5Mo3 | DIN/EN alloy designation | German/European compositional shorthand |
| AMS 5662 | SAE AMS | Solution treated bars, forgings, and rings - this specification |
| AMS 5663 | SAE AMS | Precipitation hardened bars, forgings, and rings |
| AMS 5664 | SAE AMS | Cold drawn bars, forgings |
Why Source AMS 5663 from Fighter Jet Metals?
Full mill certifications on every order
Heat number, lot number, chemical analysis, and mechanical test reports included with every shipment
Complete heat-lot traceability
Full chain-of-custody documentation from mill to your door
AS9100-certified aerospace sourcing
Material from AS9100-certified mills only
OEM specification support
Stock and supply to Boeing BMS/DMS, Gulfstream GMS, Honeywell EMS, Safran DMD, and Airbus AIPS requirements
In-house processing
Plate saw cutting, shearing, and laser cutting available; custom-cut sizes to your dimensions
Same-day quote response
Competitive pricing with rapid quote turnaround
Certified Material for Critical Service
Materials supplied in 6Al-4V titanium must meet strict aerospace certification and traceability requirements. Fighter Jet Metals supports sourcing across a wide range of AMS, MIL, and OEM specifications, ensuring compliance with industry standards.
All material is supplied with full mill certifications, complete heat-lot traceability, and detailed documentation. This ensures reliability and suitability for safety-critical aerospace, defense, and high-performance engineering applications.