AMS 5734 - A286 (UNS S66286) Bars & Forgings (Solution Heat Treated)
What is AMS 5734?
AMS 5734 is the SAE International aerospace material specification for A286 (UNS S66286), an austenitic precipitation-hardenable iron-nickel-chromium superalloy with additions of molybdenum, titanium, aluminum, boron, and vanadium, supplied in the forms of bars and forgings in the solution heat treated condition.
The nominal composition is 26Ni-15Cr-1.25Mo-2.15Ti-0.20V-0.20Al-0.05C-0.006B (Fe balance).
AMS 5734 specifies solution heat treatment at 1650°F (900°C) and quench – the lowest solution heat treatment temperature in the A286 bars and forgings specification family, lower than the 1800°F (980°C) cycle of AMS 5731.
This lower solution temperature is the key defining characteristic of AMS 5734: it produces a finer recrystallized grain structure compared to A286 solution treated at 1800°F (980°C), which can improve fatigue resistance and grain boundary properties in certain fatigue-critical applications where the 1650°F (900°C) SHT cycle is specified by the OEM drawing.
In the solution heat treated condition per AMS 5734, A286 achieves a minimum tensile strength of 130 ksi (896 MPa) and a minimum yield strength of 85 ksi (586 MPa).
A286 maintains strength and oxidation resistance at temperatures up to 1,300°F (704°C), and retains its non-magnetic, austenitic structure down to cryogenic temperatures of −320°F (−196°C).
AMS 5734 Available Forms and Stocked Sizes
Primary product form for AMS 5734; supplied in the solution heat treated condition at 1650°F (900°C) in diameters from 0.1875″ to over 14.000″; stocked in standard lengths with saw-cutting to customer dimension available.
Solution heat treated at 1650°F (900°C) per AMS 5734; available in custom cross-sections for machining into precision hardware, fasteners, and structural components.
Near-net-shape part produced by hot compressive deformation for optimized grain flow; supplied in the solution heat treated condition per AMS 5734 with full CMTRs including documented 1650°F (900°C) SHT temperature for subsequent customer aging.
Fighter Jet Metals supplies A286 per AMS 5734 in round bar, flat bar, and forging forms in the solution heat treated condition at 1650°F (900°C).
All material is supplied with full certified mill test reports (CMTR) documenting the solution heat treatment cycle, chemical analysis, and mechanical test certifications.
Applications of AMS 5734
Aerospace & Gas Turbine Applications
- High-temperature jet engine fasteners (turbine bolts, wheel studs, engine case bolts) fabricated from AMS 5734 round bar in the solution heat treated condition for subsequent customer aging to service-ready strength, on programs where the OEM drawing specifically calls out the 1650°F (900°C) SHT cycle
- Precision aerospace fasteners requiring fine grain A286 bar in the solution heat treated condition at 1650°F (900°C) for specific OEM qualification programs
- Turbine engine structural forgings and near-net-shape forged components solution heat treated per AMS 5734 for subsequent machining and aging
- Aircraft engine assembly hardware and high-temperature fasteners for both commercial and military programs where the OEM drawing specifies AMS 5734 as the procurement standard
- Turbine engine hardware requiring the specific 1650°F (900°C) SHT temperature for GE, Rolls-Royce, Pratt & Whitney, and Safran engine programs
Industrial and Energy Applications
- Industrial gas turbine (IGT) fasteners and structural hardware for land-based power generation applications where the OEM maintenance procedure or original build specification calls out AMS 5734
- Non-magnetic A286 structural components requiring the 1650°F (900°C) SHT cycle for cryogenic applications down to -320°F (-196°C)
- Precision machined A286 bar components for industrial turbomachinery applications requiring post-machining precipitation aging, sourced to AMS 5734
Defense Applications
- Military aircraft engine high-temperature fasteners and bolts in the solution heat treated condition per AMS 5734 for programs requiring the 1650°F (900°C) SHT cycle
- Defense turbine engine forgings for structural engine hardware requiring AMS 5734 traceability and solution heat treatment documentation
- High-temperature fasteners and structural components for fighter aircraft and military rotorcraft engine programs specifying AMS 5734
- Engine structural hardware requiring full AS9100D-traceable A286 bar in the solution heat treated condition at 1650°F (900°C)
Chemical Composition - AMS 5734
The following chemical composition limits apply to A286 (UNS S66286) per AMS 5734:
| Element | Symbol | Minimum % | Maximum % |
|---|---|---|---|
| Iron | Fe | - | Balance |
| Nickel | Ni | 24.0 | 27.0 |
| Chromium | Cr | 13.5 | 16.0 |
| Boron | B | 0.003 | 0.010 |
| Molybdenum | Mo | 1.00 | 1.50 |
| Vanadium | V | 0.10 | 0.50 |
| Titanium | Ti | 1.90 | 2.35 |
| Aluminum | Al | - | 0.35 |
| Phosphorus | P | - | 0.030 |
| Carbon | C | - | 0.08 |
| Manganese | Mn | - | 2.00 |
| Silicon | Si | - | 1.00 |
| Copper | Cu | - | 0.50 |
| Sulfur | S | - | 0.020 |
Nickel (24.0–27.0%) is the primary matrix element that provides the austenitic face-centered cubic crystal structure, stable from cryogenic temperatures to the alloy’s service limit.
The high nickel content combined with chromium gives A286 its characteristic non-magnetic behavior in all conditions, including cryogenic service down to −320°F (−196°C).
Chromium (13.5–16.0%) provides oxidation resistance and hot corrosion resistance in gas turbine environments; the nominal 15% chromium level provides corrosion protection without requiring additional coatings for most aerospace applications up to 1,300°F (704°C).
Molybdenum (1.00–1.50%) contributes solid-solution strengthening of the iron-nickel-chromium matrix and improves pitting corrosion resistance.
Titanium (1.90–2.35%) is the primary precipitation hardening element: during customer aging, titanium reacts with nickel to form coherent gamma-prime (γ’) precipitates (Ni₃Ti-based) that are the dominant strengthening mechanism in A286.
In the solution heat treated condition per AMS 5734 at 1650°F (900°C), titanium is dissolved into solid solution (along with boron and vanadium) in preparation for subsequent precipitation aging.
Vanadium (0.10–0.50%) improves notch sensitivity and fatigue resistance, which is particularly relevant for the fatigue-critical applications in which AMS 5734’s finer grain structure is preferred.
Boron (0.003–0.010%) and Aluminum (max 0.35%) are grain boundary strengtheners that improve stress rupture life and elevated-temperature creep resistance.
Iron is the balance element; the high iron content gives A286 a density similar to stainless steel (0.286 lb/in³ / 7.92 g/cm³), significantly lower than nickel-based superalloys – a weight advantage in fastener and structural aerospace component applications.
Mechanical Properties - AMS 5734
Minimum mechanical properties for A286 per AMS 5734 in the solution heat treated (SHT) condition:
| Property | Imperial | Metric |
|---|---|---|
| Tensile Strength (min) | 130,000 psi (130 ksi) | 896 MPa |
| Yield Strength, 0.2% offset (min) | 85,000 psi (85 ksi) | 586 MPa |
| Elongation in 2 in. or 4D (min) | 25% | 25% |
| Reduction in Area (min) | 25% | 25% |
Elevated Temperature Properties - AMS 5734
The following elevated temperature properties are for A286 (UNS S66286) in the precipitation aged condition after starting from the AMS 5734 solution heat treated condition.
These are representative typical values from published literature (Carpenter Technology / Special Metals Technical Data):
| Temperature | Tensile Strength (typical) | Yield Strength (typical) | Elongation (typical) |
|---|---|---|---|
| Room Temp (70°F / 21°C) | 145 ksi (1000 MPa) | 100 ksi (690 MPa) | 22% |
| 400°F (204°C) | 140 ksi (965 MPa) | 98 ksi (676 MPa) | 20% |
| 800°F (427°C) | 135 ksi (931 MPa) | 97 ksi (669 MPa) | 18% |
| 1000°F (538°C) | 130 ksi (896 MPa) | 93 ksi (641 MPa) | 17% |
| 1200°F (649°C) | 110 ksi (758 MPa) | 84 ksi (579 MPa) | 16% |
| 1300°F (704°C) | 82 ksi (565 MPa) | 64 ksi (441 MPa) | 18% |
Physical Properties - AMS 5734
| Property | Value (Imperial) | Value (Metric) |
|---|---|---|
| Density | 0.286 lb/in³ | 7.92 g/cm³ |
| Solidus Temperature | ~2500°F | ~1371°C |
| Liquidus Temperature | ~2540°F | ~1393°C |
| Modulus of Elasticity | 29.1 × 10⁶ psi | 201 GPa |
| Thermal Conductivity | 6.8 BTU/(hr·ft·°F) | 11.8 W/(m·K) |
| Thermal Conductivity (1200°F) | 9.2 BTU/(hr·ft·°F) | 15.9 W/(m·K) |
| Coefficient of Thermal Expansion | 9.2 × 10⁻⁶ /°F | 16.6 × 10⁻⁶ /°C |
| Specific Heat | 0.110 BTU/(lb·°F) | 460 J/(kg·K) |
| Max Service Temperature (Rotating Load) | 1300°F | 704°C |
| Max Service Temperature (Static / Structural) | 1500°F | 816°C |
| Solution Heat Treatment Temperature | 1800°F (980°C) / 1 hr min | - |
| Magnetic Permeability | Non-magnetic (austenitic) | - |
AMS 5734 vs AMS 5731 vs AMS 5726 - Which Specification Do You Need?
All three are SAE AMS specifications for A286 (UNS S66286) bars and forgings in the solution heat treated condition, but they differ in the specified solution heat treatment temperature, melt practice requirements, and intended application.
The applicable specification for a given part is governed by the OEM engineering drawing or purchase order:
| Feature | AMS 5734 | AMS 5731 | AMS 5726 |
|---|---|---|---|
| Alloy | A286 (UNS S66286) | A286 (UNS S66286) | A286 (UNS S66286) |
| Product Forms | Bars, Forgings | Bars, Forgings | Bars, Forgings |
| Condition | Solution Heat Treated | Solution Heat Treated | Solution Heat Treated |
| Tensile Strength (min SHT) | 130 ksi (896 MPa) | 130 ksi (896 MPa) | 130 ksi (896 MPa) |
| Yield Strength (min SHT) | 85 ksi (586 MPa) | 85 ksi (586 MPa) | 85 ksi (586 MPa) |
| SHT Temperature | 1650°F (900°C) - explicitly stated | 1800°F (980°C) / 1 hr min | Per spec (consult current revision) |
| SHT Comparison | Lowest SHT temperature in the A286 SHT bars & forgings family - 150°F (83°C) lower than AMS 5731 | Standard A286 SHT temperature - most widely specified for general A286 bars and forgings | Per spec - SHT temperature not the primary distinguishing requirement |
| Melt Practice | - | - | Consumable electrode required (VIM + VAR) |
| Key Characteristic | Lower 1650°F (900°C) SHT temperature - finer recrystallized grain structure; specified when OEM drawing calls out the 1650°F cycle | Standard A286 SHT specification with specific 1800°F (980°C) solution temperature requirement | Consumable electrode melt + SHT - standard procuring specification for A286 bars and forgings with full melt traceability |
| Typical Application | A286 bars and forgings where OEM drawing specifically requires the 1650°F (900°C) solution heat treatment cycle | Engine hardware, turbine components, and structural parts requiring the standard A286 SHT condition | High-temperature fasteners, turbine engine bolts, structural forgings requiring melt traceability |
Specify AMS 5734 when and only when the OEM engineering drawing calls out AMS 5734 or explicitly requires the 1650°F (900°C) solution heat treatment cycle.
Specify AMS 5731 when the drawing requires the standard 1800°F (980°C) SHT cycle.
Specify AMS 5726 when the drawing requires consumable electrode melt (VIM+VAR) traceability documented on the CMTR.
Always confirm the specification number on the engineering drawing before procurement – do not substitute one A286 SHT spec for another without written engineering approval, as the different SHT temperatures can produce measurable differences in grain size and aging response.
Approved Mill Producers
Fighter Jet Metals sources A286 per AMS 5734 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 (spectrographic), and mechanical test certifications traceable to the originating mill heat and documented solution heat treatment at 1650°F (900°C).
AMS 5734 Machining Guidelines
A286 per AMS 5734 is supplied in the solution heat treated condition at 1650°F (900°C), which provides the best machinability of any A286 delivery condition.
The SHT condition delivers lower hardness, higher ductility, and reduced tendency to work-harden rapidly compared to cold-worked (AMS 5853) or aged material.
For AMS 5734, the finer grain structure resulting from the lower SHT temperature may provide slightly improved surface finish and chip control compared to coarser-grained AMS 5731 material, which is an additional benefit in precision machining applications.
Key machining considerations for AMS 5734 bars and forgings in the solution heat treated condition:
- Work hardening: A286 in the SHT condition work-hardens more rapidly than standard austenitic stainless steels (304, 316). Continuous cutting with no dwell is required to prevent work-hardening ahead of the tool
- Turning and boring: Positive-rake carbide tooling (C2 or C3 carbide, PVD TiAlN coated) recommended; rigid setup required; speeds of 100–200 SFM with flood coolant
- Thread machining: Thread rolling strongly preferred over thread cutting for bolt and fastener manufacturing from AMS 5734 bar – roll threading in the SHT condition, then precipitation age to produce the specified tensile strength on the finished fastener
- Drilling: High-speed steel drills acceptable for small diameters; cobalt HSS or solid carbide drills recommended for diameters above 0.25″; peck drilling with flood coolant
- Milling: Climbing (down) milling preferred to prevent work-hardening at the cut surface; positive-rake carbide endmills; feed rates high enough to maintain chip load and avoid rubbing
- Coolant: High-pressure flood coolant required at all times; sulfurized or chlorinated cutting oils for difficult features (deep holes, thread cutting)
- Chip control: A286 SHT produces long, stringy chips – chip breaker geometry essential in turning operations; built-up edge formation is the primary tool failure mode
Weldability of AMS 5734
A286 per AMS 5734 is supplied in the solution heat treated (unaged) condition and is weldable in this delivery state.
Because the material has not been precipitation aged, the risk of strain-age cracking (SAC) in the heat-affected zone is significantly lower than for aged material.
For AMS 5734 weldments, the same welding practices as other A286 SHT specifications apply:
- TIG (GTAW): Primary welding process for AMS 5734 A286 bars and forgings in the SHT condition; minimum heat input; argon shielding gas; filler metal AMS 5798 (A286-type filler, ER CRNI-2 equivalent) recommended
- Electron Beam (EBW): Used in precision aerospace applications requiring minimal heat input and narrow heat-affected zone; performed in vacuum for contamination control
- Preheat: Generally not required for thin sections; for thick bar or forging sections (>0.5″), a preheat of 200–300°F (93–149°C) and controlled interpass temperature reduces thermal gradient cracking risk
- Post-weld heat treatment (PWHT): For weldments requiring full precipitation hardened properties, a complete precipitation aging cycle (1325°F / 718°C / 16 hours minimum / air cool) is applied after welding and before final inspection
- Recommended fabrication sequence: Machine all features in SHT condition (AMS 5734) → weld as required → inspect weld quality → precipitation age to service properties → finish machine and final inspect
- Contrast with aged condition: A286 that has been precipitation aged has significantly higher SAC susceptibility than AMS 5734 SHT material. Weldment repair on aged A286 hardware requires careful procedure qualification and typically re-solution treatment before welding
Melt Practice - AMS 5734
AMS 5734 covers A286 (UNS S66286) bars and forgings in the solution heat treated condition at 1650°F (900°C).
AMS 5734 does not impose a consumable electrode melt requirement (unlike AMS 5726 and AMS 5895, which explicitly require consumable electrode melting documented on the CMTR).
The solution heat treatment cycle specified in AMS 5734 – 1650°F (900°C) and quench – is the lowest solution temperature in the A286 bar and forging specification family, and this distinction has direct metallurgical consequences for the delivered microstructure.
Effect of the 1650°F (900°C) SHT Temperature vs 1800°F (980°C):
The solution heat treatment temperature determines the grain size of the fully recrystallized austenite matrix after quenching.
At 1650°F (900°C), grain boundary pinning by remaining undissolved carbide particles and the lower available thermal energy for grain boundary migration result in a finer recrystallized grain structure compared to the same alloy solution treated at 1800°F (980°C) per AMS 5731. The practical consequences for AMS 5734 bars and forgings include:
- Finer grain size: The lower SHT temperature restrains grain growth kinetics, producing a finer austenite grain structure in the delivered bar or forging; fine grain (higher ASTM grain size number) is often beneficial for fatigue-loaded applications due to the Hall-Petch relationship between grain size and yield strength
- Grain boundary characteristics: At 1650°F (900°C), partial carbide dissolution at grain boundaries can affect grain boundary chemistry, which influences stress rupture and creep behavior differently than material solution treated at 1800°F (980°C)
- Aging response: The degree of titanium solid solution at 1650°F (900°C) may be slightly different from 1800°F (980°C) SHT; customers should verify aging response against the expected properties for the specific OEM drawing before final processing
- OEM drawing specificity: Because the SHT temperature is the key distinguishing parameter of AMS 5734, the applicable specification is strictly governed by the engineering drawing – do not substitute AMS 5734 for AMS 5731 (or vice versa) without written engineering approval from the OEM
Always confirm the documented solution heat treatment temperature and quench medium on the certified mill test report (CMTR) for each AMS 5734 procurement.
Verify any melt practice requirements on the OEM drawing.
AMS 5734 Cross-Reference Specifications
SHEET & PLATE
A286 flat-rolled specifications covering sheet, strip, and plate product forms – the flat-product counterparts to AMS 5734 bars and forgings.
BARS & FORGINGS
A286 bar and forging specifications in various heat treat conditions – the sibling specifications to AMS 5734 for different SHT temperatures, melt practice requirements, or downstream processing applications.
GE SPECIFICATIONS
GE Aviation quality and material procurement specifications covering A286 product forms used in GE-designed aircraft engine programs.
ROLLS ROYCE SPECIFICATIONS
Rolls-Royce material quality specifications for A286 product forms used in Rolls-Royce turbine and aircraft engine hardware.
PRATT & WHITNEY SPECIFICATIONS
Pratt & Whitney material procurement specification for A286 bars covering aircraft engine applications.
SAFRAN SPECIFICATIONS
Safran / CFM International material specification for A286 covering Safran-designed aerospace engine component programs.
Trade Names and Equivalent Designations
A286 per AMS 5734 is known by the following trade names and equivalent designations across different standards systems:
| Designation | System | Notes |
|---|---|---|
| A-286 / A286 | Common name | Widely used commercial designation; the hyphen is optional |
| Iron Alloy S66286 | Generic name | Generic iron-based superalloy designation for non-proprietary procurement |
| AISI 660 | AISI | designation sometimes used for A286 in commercial sourcing |
| ASTM A638 Gr. 660 | ASTM specification | Precipitation-hardening iron-base superalloy bars, forgings, and rings - includes UNS S66286 (Grade 660) |
| AMS 5734 | SAE AMS | Solution heat treated bars and forgings at 1650°F (900°C) |
| AMS 5726 | SAE AMS | Solution heat treated bars and forgings |
| UNS S66286 | UNS (Unified Numbering System) | Standard material identifier in North America |
| DIN 1.4980 / W.Nr. 1.4980 | Werkstoff Nr. (German) | European material number designation |
| AMS 5731 | SAE AMS | Solution heat treated bars and forgings - 1800°F SHT, related specification |
| AMS 5732 | SAE AMS | Solution-strengthened bars and forgings |
| AMS 5525 | SAE AMS | Solution heat treated sheet, strip, and plate |
| AMS 5853 | SAE AMS | Cold-worked and work-strengthened bars and wire |
| AMS 5895 | SAE AMS | Solution heat treated bars, wire, forgings, tubing, rings - 1750°F SHT, consumable electrode |
Why Source AMS 5734 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
SHT temperature traceability
1650°F (900°C) solution heat treatment cycle documented on every CMTR; AMS 5734 SHT temperature verified and traceable from mill to your door
AS9100D-certified aerospace sourcing
Material sourced from AS9100D-certified mills only
OEM specification support
Stock and supply to GE B50T1181C, B50T12, B50T81, MSRR 6531/6532/6688, PWA-S-5732, and DMD 0274-22 requirements in addition to AMS 5734 and related AMS 5525, 5726, 5731, 5732, 5737, 5853, and 5895 specifications
In-house processing
Bar saw cutting to length, trepanning (hollow bar), lathe work (turning), and shearing 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.