AMS 5707 - Waspaloy (UNS N07001) Rings, Forgings & Forging Stock (Precipitation Hardened)
What is AMS 5707?
AMS 5707 is the SAE International aerospace material specification for Waspaloy (UNS N07001), a precipitation-hardenable nickel-chromium-cobalt superalloy with molybdenum, titanium, aluminum, boron, and zirconium additions, supplied in the forms of rings, forgings, and forging stock in the solution and precipitation heat treated condition.
The nominal composition is 57.0Ni-19.5Cr-13.5Co-4.3Mo-3.0Ti-1.4Al-0.07C-0.006B-0.06Zr.
In the precipitation hardened condition per AMS 5707, Waspaloy achieves a minimum tensile strength of 185 ksi (1276 MPa), a minimum yield strength of 155 ksi (1069 MPa), and a minimum elongation of 15%.
The ring form covered by AMS 5707 – produced by ring-rolling or open-die forging to a toroidal shape – is the standard product form for turbine containment rings, engine case flanges, rotor spacer rings, and compressor ring assemblies that require the full precipitation hardened strength at delivery without subsequent heat treatment by the customer.
AMS 5707 is the standard specification for Waspaloy ring forgings required at full design strength for jet engine hot-section and structural ring applications operating up to 1200°F (649°C) under sustained mechanical load in rotating service.
AMS 5706 Available Forms and Stocked Sizes
Rolled or open-die forged toroidal ring in the precipitation hardened condition; supplied to customer drawing per OD, ID, and face dimensions with full CMTRs.
ear-net-shape part produced by hot compressive deformation for optimized grain flow; supplied fully solution + precipitation heat treated per AMS 5707 requirements.
As-forged or as-rolled billet preform for subsequent finish forging by the customer; supplied in the precipitation hardened condition per AMS 5707 with full CMTRs.
Fighter Jet Metals supplies Waspaloy per AMS 5707 in ring forgings, finished forgings, and forging stock in the precipitation hardened condition.
All material is supplied with full certified mill test reports (CMTR) and certificates of conformance.
Applications of AMS 5707
Aerospace & Gas Turbine Applications
- Turbine containment rings and engine case rings in the precipitation hardened condition, ready for final precision bore, OD, and face machining and direct service
- Compressor disc spacer rings, spool rings, and flange rings for hot-section engine assemblies requiring full precipitation hardened strength
- Rotor and stator ring assemblies for axial flow compressors and turbines in commercial and military aircraft engines
- Engine structural ring forgings and flanges for turbofan, turbojet, and turboprop engines
- Turbine disc and compressor disc forgings where ring-rolling or open-die forging is the preferred process for grain flow optimization
- Ring-form forging stock and billet preforms for aerospace forging houses manufacturing engine ring hardware
- Gas turbine hot-section ring and forging hardware for both commercial and military aircraft engines
Power Generation and Industrial Applications
- Land-based industrial gas turbine (IGT) hot-section ring hardware at full precipitation hardened strength
- Turbine containment and casing rings for power generation turbines operating in sustained high-temperature service
- High-temperature structural ring forgings for industrial applications requiring combined strength and thermal stability
- Nuclear power plant and energy sector structural ring and forging hardware requiring precipitation hardened delivery condition
Defense Applications
- Military aircraft gas turbine engine containment rings and case rings in the fully precipitation hardened condition at full design strength
- Turbine engine ring hardware for fighter aircraft, bombers, and attack helicopters where precipitation hardened delivery condition is specified
- Defense propulsion ring components requiring full Boeing BMS 7-171, Safran DMD 0246-22, or AMS 5707 traceability in the precipitation hardened condition
- Turboprop and turboshaft engine ring assemblies and structural forgings for military rotorcraft in service-ready condition
- Missile and airframe ring structural forgings requiring combined high-temperature strength and full certification
Chemical Composition - AMS 5707
The following chemical composition limits apply to Waspaloy (UNS N07001) per AMS 5707:
| Element | Symbol | Minimum % | Maximum % |
|---|---|---|---|
| Nickel | Ni | Balance | - |
| Chromium | Cr | 18.0 | 21.0 |
| Iron | Fe | - | 2.00 |
| Boron | B | 0.003 | 0.010 |
| Molybdenum | Mo | 3.5 | 5.0 |
| Cobalt | Co | 12.0 | 15.0 |
| Titanium | Ti | 2.75 | 3.25 |
| Aluminum | Al | 1.20 | 1.60 |
| Zirconium | Zr | 0.02 | 0.12 |
| Carbon | C | 0.02 | 0.10 |
| Manganese | Mn | - | 0.10 |
| Silicon | Si | - | 0.75 |
| Copper | Cu | - | 0.10 |
| Sulfur | S | - | 0.015 |
Cobalt (12.0–15.0%) is the second-largest alloying element in Waspaloy and is a primary contributor to the alloy’s solid-solution strengthening – Waspaloy contains significantly more cobalt than Inconel 718, which gives it superior strength at temperatures above 1200°F (649°C) compared to lower-cobalt nickel alloys.
Chromium (18.0–21.0%) provides oxidation and hot corrosion resistance.
Molybdenum (3.5–5.0%) contributes further solid-solution strengthening to the nickel matrix.
Titanium (2.75–3.25%) and Aluminum (1.20–1.60%) are the principal precipitation hardening elements, forming the gamma-prime (γ’) phase Ni₃(Al,Ti) during the precipitation aging heat treatment.
The combined Al+Ti content of Waspaloy (~4.0–4.85%) is significantly higher than Inconel 718 (~1.0–1.6%), making Waspaloy stronger at elevated temperatures but more challenging to weld.
Boron (0.003–0.010%) and Zirconium (0.02–0.12%) are grain-boundary-strengthening additions that improve high-temperature creep resistance and stress rupture life – trace elements that are critical to Waspaloy’s long-term performance in gas turbine hardware.
Iron is strictly limited to 2.00% maximum to maintain the thermal stability of the γ’ phase at elevated temperatures.
Mechanical Properties - AMS 5707
Minimum mechanical properties required by AMS 5707 for Waspaloy rings, forgings, and forging stock in the precipitation hardened (solution + aged) condition:
| Property | Imperial | Metric |
|---|---|---|
| Tensile Strength (min) | 185,000 psi (185 ksi) | 1,276 MPa |
| Yield Strength, 0.2% offset (min) | 155,000 psi (155 ksi) | 1,069 MPa |
| Elongation in 2 in. or 4D (min) | 15% | 15% |
| Reduction in Area (min) | 18% | 18% |
Elevated Temperature Properties - AMS 5707
The following elevated temperature properties are for Waspaloy in the precipitation hardened condition per AMS 5707.
These are representative typical values from published literature (Carpenter Technology / Special Metals Technical Bulletin):
| Temperature | Tensile Strength (typical) | Yield Strength (typical) | Elongation (typical) |
|---|---|---|---|
| Room Temp (70°F / 21°C) | 195 ksi (1345 MPa) | 165 ksi (1138 MPa) | 22% |
| 600°F (316°C) | 183 ksi (1262 MPa) | 157 ksi (1082 MPa) | 18% |
| 1000°F (538°C) | 178 ksi (1227 MPa) | 151 ksi (1041 MPa) | 16% |
| 1200°F (649°C) | 158 ksi (1089 MPa) | 137 ksi (945 MPa) | 14% |
| 1400°F (760°C) | 102 ksi (703 MPa) | 87 ksi (600 MPa) | 14% |
Physical Properties - AMS 5707
| Property | Value (Imperial) | Value (Metric) |
|---|---|---|
| Density | 0.296 lb/in³ | 8.19 g/cm³ |
| Melting Range | ~2330°F–2380°F | ~1277°C–1304°C |
| Modulus of Elasticity | 31.4 × 10⁶ psi | 217 GPa |
| Thermal Conductivity | 6.8 BTU/(hr·ft·°F) | 11.8 W/(m·K) |
| Thermal Conductivity (1200°F) | 10.4 BTU/(hr·ft·°F) | 18.0 W/(m·K) |
| Coefficient of Thermal Expansion | 7.8 × 10⁻⁶ /°F | 14.0 × 10⁻⁶ /°C |
| Specific Heat | 0.107 BTU/(lb·°F) | 448 J/(kg·K) |
| Max Service Temperature (Rotating Load) | 1200°F | 649°C |
| Max Service Temperature (Static / Structural) | 1600°F | 870°C |
| Melt Practice | VIM + VAR (double melt) | - |
AMS 5707 vs AMS 5709 vs AMS 5704 - Which Specification Do You Need?
All three are SAE AMS specifications for Waspaloy (UNS N07001) covering ring and forging product forms, but they differ in heat treatment condition and scope:
| Feature | AMS 5707 | AMS 5709 | AMS 5704 |
|---|---|---|---|
| Alloy | Waspaloy (UNS N07001) | Waspaloy (UNS N07001) | Waspaloy (UNS N07001) |
| Product Forms | Rings, Forgings, Forging Stock | Forgings, Rings, Forging Stock | Bars, Forgings, Rings |
| Condition | Precipitation Hardened | Precipitation Hardened | Solution Heat Treated |
| Tensile Min | 185 ksi (1276 MPa) | See current revision | 130 ksi (896 MPa) |
| Yield Strength (min) | 155 ksi (1069 MPa) | See current revision | 80 ksi (552 MPa) |
| Elongation (min) | 15% | See current revision | 20% |
| Primary Use | Ring forgings and forging stock at full precipitation hardened condition - ring-form counterpart to AMS 5706 | Waspaloy forgings, rings, and stocks for critical rotating parts in the precipitation hardened condition - companion spec to AMS 5707; consult OEM drawing for which applies | Machining stock for complex engine disc and shaft machining before final aging |
| Key Advantage | Specifically addresses ring product forms requiring the precipitation hardened condition | Similar scope to AMS 5707; specific OEM drawings will call out which specification applies | Maximum machinability and ductility for complex engine hardware machining before heat treatment |
Specify AMS 5707 when procuring Waspaloy ring forgings or forging stock at full precipitation hardened strength, or when the OEM drawing calls out AMS 5707.
Specify AMS 5709 when the OEM drawing calls out AMS 5709 (both are PH ring/forging specs – the OEM drawing or purchase order governs).
Specify AMS 5704 when procuring ring stock or forging stock for machining before heat treatment.
Approved Mill Producers
Fighter Jet Metals sources AMS 5707 Waspaloy ring forgings and forging 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).
AMS 5707 Machining Guidelines
AMS 5707 Waspaloy is supplied in the fully precipitation hardened condition – the highest-strength delivery condition for Waspaloy ring forgings and forging stock.
Machining precipitation hardened Waspaloy is significantly more difficult than machining solution treated (AMS 5704) material. When the engineering drawing or purchase order permits, procurement to AMS 5704 (solution treated) followed by ring forging and machining, then precipitation aging to AMS 5707 properties is the preferred sequence for complex ring hardware, as it greatly reduces machining time and tooling cost.
Ring-specific machining considerations for AMS 5707:
- Work hardening: Precipitation hardened Waspaloy work-hardens extremely rapidly – more aggressively than AMS 5704 solution treated material or Inconel 718. Continuous cuts with no dwell are mandatory at all times for bore, OD, and face turning of ring forgings
- Bore and OD turning: Rigid setup with steady support of the ring OD during bore operations; internal boring bars must be as short and rigid as possible; minimum overhang; high-pressure coolant directed at the cutting zone
- Face turning: Low depth of cut in the PH condition to maintain dimensional control and prevent chatter on large ring faces; sharp positive-rake tooling
- Cutting speeds: 20–40 SFM for carbide tooling in the precipitation hardened condition – significantly slower than AMS 5704 solution treated stock
- Feeds: Aggressive feeds relative to speed to maintain chip formation and minimize heat accumulation at slow cutting speeds
- Tooling: Premium PVD-coated carbide (TiAlN or AlTiN coating); CBN tooling for finish turning and grinding operations on hardened surfaces
- Coolant: High-pressure flood coolant required at all times; sulfurized or chlorinated cutting oils provide best tool life for bore and internal features
- Chip control: Precipitation hardened Waspaloy produces tough, short, work-hardened chips – chip breaker geometry essential in all bore, OD, and face operations
Weldability of AMS 5707
Waspaloy per AMS 5707 is in the precipitation hardened condition and should not be welded in this condition without full solution re-treatment after welding.
The precipitation hardened condition has maximum susceptibility to strain-age cracking (SAC) – the combination of high residual stresses from welding and the strong driving force for γ’ re-precipitation in the HAZ creates a high risk of immediate or delayed HAZ cracking.
This risk is particularly acute in ring and forging sections due to high mass and constrained residual stress geometry.
For welded Waspaloy ring assemblies:
- Pre-weld condition: Welding must be performed on material in the solution heat treated condition (AMS 5704) – never weld Waspaloy in the precipitation hardened (AMS 5707) condition
- TIG (GTAW): Primary welding process for Waspaloy in the solution treated condition; minimum heat input; argon shielding required; filler metal AWS A5.14 ERNiCrCoMo-1 (Waspaloy-type filler) recommended
- Electron Beam (EBW): Used in aerospace applications requiring minimal heat input and the narrowest possible heat-affected zone; performed in vacuum
- Preheat: Preheat to 200–300°F (93–149°C) recommended for thick ring sections; controlled interpass temperature essential
- Post-weld heat treatment (PWHT): Full solution treat followed by the two-stage precipitation aging cycle is required to restore base metal and weld metal properties; any AMS 5707 ring or forging that has been welded must be fully re-heat-treated
- Contrast with Inconel 718: Inconel 718 is far more weldable than Waspaloy because it relies on the Nb-containing γ” phase (slow precipitation kinetics) rather than the Al+Ti γ’ phase (rapid precipitation kinetics). For welded ring assemblies, Inconel 718 is strongly preferred over Waspaloy wherever the design permits
Melt Practice - AMS 5707
To produce Waspaloy per AMS 5707, 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, nitrogen, and hydrogen from the melt.
The primary VIM ingot is then remelted using Vacuum Arc Remelting (VAR), also referred to as consumable electrode remelting.
This VIM+VAR double-melt process eliminates segregation, macro-inclusions, and compositional gradients 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 ring components – turbine containment rings, engine case rings – triple-melt processing (VIM + ESR + VAR) may be required by some OEM procurement specifications to further reduce inclusion count and improve fatigue life.
Always confirm the melt practice on the certified mill test report before procurement.
AMS 5707 Cross-Reference Specifications
Sheets & Plates
Waspaloy flat-rolled specification for aerospace sheet metal fabrication in the solution heat treated condition.
Bars, Forgings & Rings (Solution Heat Treated)
Waspaloy bars, forgings, and rings in the solution heat treated condition – the machining stock form of the same material before final precipitation aging to AMS 5707 properties.
Bars & Forgings (Precipitation Hardened)
Waspaloy bars and forgings in the precipitation hardened condition – the bar-form counterpart to AMS 5707 ring and forging forms.
Rings & Forgings (Precipitation Hardened)
Waspaloy forgings, rings, and forging stock in the precipitation hardened condition – the companion specification to AMS 5707 for critical rotating ring and forging applications.
Boeing Specifications
Boeing material specification for Waspaloy bars and forgings covering Boeing’s aerospace and engine manufacturing quality requirements.
Safran / Snecma
Safran/Snecma material specification for Waspaloy bars and forgings for French-designed turbofan engine rotating and structural components.
Trade Names and Equivalent Designations
Waspaloy per AMS 5707 is known by the following trade names and equivalent designations across different standards systems:
| Designation | System | Notes |
|---|---|---|
| Waspaloy / WASPALOY® | Trade name | Registered trademark of Precision Castparts Corp (originally developed by United Aircraft / Pratt & Whitney); most widely used commercial name |
| Nickel Alloy 1 / Nickel Alloy N07001 | Common name | Generic material designation used in non-proprietary procurement documents |
| ASTM B637 | ASTM specification | Precipitation-hardening nickel alloy bars, forgings, and forging stock for high-temperature service |
| AMS 5704 | SAE AMS | Solution heat treated bars, forgings, and rings |
| UNS N07001 | UNS (Unified Numbering System) | Standard material identifier in North America |
| DIN 2.4654 / W.Nr. 2.4654 | Werkstoff Nr. (German) | European material number designation |
| AMS 5706 | SAE AMS | Precipitation hardened bars, forgings |
| AMS 5707 | SAE AMS | Precipitation hardened rings, forgings, forging stock |
| AMS 5709 | SAE AMS | Precipitation hardened forgings, rings, and forging stock 6 companion specification |
Why Source AMS 5707 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
AS9100D-certified aerospace sourcing
Material sourced from AS9100D-certified mills only
OEM specification support
Stock and supply to Boeing BMS 7-171 and Safran DMD 0246-22 requirements in addition to AMS 5704, AMS 5706, AMS 5707, and AMS 5709
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.