AMS 5706 - Waspaloy (UNS N07001) Bars & Forgings (Precipitation Hardened)
What is AMS 5706?
AMS 5706 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 bars and forgings 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 5706, 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 precipitation hardened condition represents the final, fully heat-treated condition of Waspaloy bars and forgings – the service-ready delivery condition for engine discs, shafts, and structural forgings that are used as-machined without subsequent aging.
AMS 5706 is the standard specification for Waspaloy bars and forgings required at full design strength for jet engine compressor and turbine discs, shafts, rings, seals, spacers, and high-temperature structural aerospace components operating up to 1200°F (649°C) under sustained mechanical load in rotating service.
AMS 5706 Available Forms and Stocked Sizes
AMS 5706 covers Waspaloy in bar and forged product forms in the precipitation hardened (solution + aged) condition.
The SAE/AMS product form definitions are:
Round, flat, square, or hexagonal solid stock in the precipitation hardened condition; supplied cut-to-length in sizes from 0.250″–12.00″ diameter with full CMTRs.
Shaped stock produced by hot compressive deformation for improved grain flow; supplied fully solution + precipitation heat treated per AMS 5706 requirements.
Fighter Jet Metals supplies Waspaloy per AMS 5706 in round bar, flat bar, and forging stock and billets.
All material is supplied in the precipitation hardened condition with full certified mill test reports (CMTR) and certificates of conformance.
Applications of AMS 5706
Aerospace & Gas Turbine Applications
- Jet engine compressor and turbine discs in the fully precipitation hardened condition, ready for precision final machining and service
- Turbine and compressor shafts, stub shafts, and coupling hardware at full design strength requiring high fatigue capability at elevated temperature
- Engine structural forgings, spacers, and spool hardware for both commercial and military turbofan engines
- High-strength bolts, studs, and fasteners for hot-section engine assembly requiring precipitation hardened strength
- Turbine engine casings and structural engine hardware requiring full precipitation hardened mechanical properties prior to finish machining
- Gas turbine hot-section hardware for military and commercial aircraft engines where the precipitation hardened delivery condition is specified
Power Generation and Industrial Applications
- Land-based industrial gas turbine (IGT) hot-section rotating hardware at full precipitation hardened strength
- Compressor discs and wheels for power generation turbines operating in sustained high-temperature service
- High-temperature valve and actuator hardware requiring full-strength precipitation hardened Waspaloy bar stock
- Nuclear power plant and energy sector structural hardware requiring combined strength and thermal stability at service-ready condition
Defense Applications
- Military aircraft and missile gas turbine engine components requiring sustained high-temperature performance at full design strength
- Turbine engine hardware for fighter aircraft, bombers, and attack helicopters where final heat treatment cannot be performed after machining
- Defense propulsion components requiring full Boeing BMS 7-171, Safran DMD 0246-22, or AMS 5706 traceability in the precipitation hardened condition
- Turboprop and turboshaft engine bars and forgings for military rotorcraft in service-ready precipitation hardened condition
Chemical Composition - AMS 5706
The following chemical composition limits apply to Waspaloy (UNS N07001) per AMS 5706:
| 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 5706
Minimum mechanical properties required by AMS 5706 for Waspaloy bars and forgings 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 5706
The following elevated temperature properties are for Waspaloy in the precipitation hardened condition per AMS 5706.
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 5706
| 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 5706 vs AMS 5704 vs AMS 5707 - Which Specification Do You Need?
All three are SAE AMS specifications for Waspaloy (UNS N07001), but they differ in product form, heat treatment condition, and intended application:
| Feature | AMS 5704 | AMS 5706 | AMS 5707 |
|---|---|---|---|
| Alloy | Waspaloy (UNS N07001) | Waspaloy (UNS N07001) | Waspaloy (UNS N07001) |
| Product Forms | Bars, Forgings, Rings | Bars, Forgings | Rings, Forgings, Forging Stock |
| Condition | Solution Heat Treated | Precipitation Hardened | Precipitation Hardened |
| Tensile Min | 130 ksi (896 MPa) | 185 ksi (1276 MPa) | See current revision |
| Yield Strength (min) | 80 ksi (552 MPa) | 155 ksi (1069 MPa) | See current revision |
| Elongation (min) | 20% | 15% | See current revision |
| Primary Use | Machining stock for complex engine disc and shaft machining before final aging | Bars and forgings at full design strength - components delivered in service-ready precipitation hardened condition | Ring forgings and forging stock at full precipitation hardened condition - ring-form counterpart to AMS 5706 |
| Key Advantage | Maximum machinability and ductility for complex engine hardware machining before heat treatment | Full tensile, yield, and fatigue strength in bar/forging form for components in service | Specifically addresses ring product forms requiring the precipitation hardened condition |
Specify AMS 5706 when procuring bars and forgings at full precipitation hardened strength for structural or engine service, or when the drawing requires precipitation hardened delivery condition.
Specify AMS 5704 when procuring bar stock or forging stock for machining before heat treatment, or when the drawing requires solution treated delivery condition.
Specify AMS 5707 when procuring ring forgings at full precipitation hardened condition.
Approved Mill Producers
Fighter Jet Metals sources AMS 5706 Waspaloy bars and forgings 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 5706 Machining Guidelines
AMS 5706 Waspaloy is supplied in the fully precipitation hardened condition – the highest-strength delivery condition for Waspaloy bars and forgings.
Machining precipitation hardened Waspaloy is significantly more difficult than machining solution treated (AMS 5704) material because hardness is at its maximum (typically 36–42 HRC equivalent in the aged condition).
When the engineering drawing or purchase order permits, procurement to AMS 5704 (solution treated) followed by machining and then precipitation aging to AMS 5706 properties is the preferred sequence for complex parts, as it greatly reduces machining time and tooling cost:
- Work hardening: Precipitation hardened Waspaloy work-hardens extremely rapidly – more aggressively than either AMS 5704 solution treated Waspaloy or Inconel 718. Continuous cuts with no dwell are mandatory at all times
- Cutting speeds: 20–40 SFM for carbide tooling in the precipitation hardened condition – significantly slower than solution treated AMS 5704 and requiring more conservative parameters than Inconel 718
- Feeds: Aggressive feeds relative to speeds recommended to maintain chip formation and minimize the heat buildup from slow-speed cutting conditions
- Tooling: Premium PVD-coated carbide (TiAlN or AlTiN coating); CBN tooling for finish turning and grinding operations on hardened surfaces; ceramic tooling suitable for roughing passes on unfeatured cylindrical surfaces only
- Coolant: High-pressure flood coolant required at all times; sulfurized or chlorinated cutting oils provide best tool life for difficult features and deep pockets
- Turning: Rigid setup with minimal bar overhang; steady rests required for long shaft sections; reduced depth of cut compared to solution treated condition
- Chip control: Precipitation hardened Waspaloy produces tough, short, work-hardened chips – chip breaker geometry essential in all operations; stringy chips are a sign of excessive cutting speed or insufficient feed
Weldability of AMS 5706
Waspaloy per AMS 5706 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.
For welded Waspaloy assemblies, the correct procedure is:
- 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 5706) 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 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 5706 bar 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 assemblies, Inconel 718 is strongly preferred over Waspaloy wherever the design permits
Melt Practice - AMS 5706
To produce Waspaloy per AMS 5706, 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 components – engine discs, turbine shafts – 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 5706 Cross-Reference Specifications
Sheets & Plates
Waspaloy flat-rolled specification for aerospace sheet metal fabrication in the solution heat treated condition.
Bars & Forgings (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 5706 properties.
Rings & Forgings
Waspaloy rings, forgings, and forging stock in the precipitation hardened condition for aerospace ring-form 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 5706 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 |
Why Source AMS 5706 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.