A286 Alloy Mechanical Properties

A286 alloy (UNS S66286) is an iron-base, age-hardenable superalloy valued for maintaining high mechanical properties at service temperatures up to 1300°F (700°C). In its standard age-hardened condition (typically AMS 5731 or AMS 5732), A286 exhibits a minimum Ultimate Tensile Strength (UTS) of 130 ksi (896 MPa) and a Yield Strength (0.2% Offset) of 85 ksi (586 MPa), combined with excellent ductility (Min 15% Elongation). Crucially, for high-stress applications like turbine fasteners or manifold components, its mechanical performance is defined by its Stress Rupture strength, capable of withstanding 65 ksi (448 MPa) at 1200°F for 23 hours without failure. Please note that these properties are heavily dependent on the heat treatment cycle (Solution + Precipitation Hardening); choosing the wrong AMS standard (e.g., confusing AMS 5731 with AMS 5737) can significantly alter the creep resistance and hardness range (typically 248–341 HBW).

Temperature Tolerance And High Temperature Performance

The core feature of A286’s mechanical properties is its ability to retain strength in extreme environments. Ordinary stainless steel may “soften” significantly when heated, but the A286 is specifically designed for efficient operation at 1300 °F (700°C). This temperature resistance makes it ideal for jet engine hot end components and industrial gas turbines.

Metallurgically, this iron-based composition, when enhanced by age hardening, ensures that the material will not undergo brittle fracture or rapid loss of structural integrity during the hot and cold cycles common to exhaust manifolds and turbine components.

The values below represent the standard AMS 5731 / AMS 5732 (Solution Treated + Aged) condition, which is the industry baseline for aerospace fasteners and turbine components.

Property	Imperial Unit	Metric Unit
Ultimate Tensile Strength	130 – 146 ksi	896 – 1005 MPa
0.2% Yield Strength	85 – 105 ksi	586 – 724 MPa
Elongation (in 4D)	15% – 25%	15% – 25%
Reduction of Area	20% – 40%	20% – 40%
Hardness (Brinell)	248 – 341 HB	248 – 341 HB
Hardness (Rockwell C)	24 – 35 HRC	24 – 35 HRC
Modulus of Elasticity	29.1 x 10⁶ psi	201 GPa

Note: If your design requires higher strength (e.g., 160 ksi UTS), cold working prior to aging (refer to AMS 5853) is required.

Engineers choose A286 not for its room temperature strength (where Inconel 718 might be superior), but for its stability in the 1000°F to 1300°F range. Unlike many stainless steels that lose integrity rapidly above 800°F, A286 maintains structural rigidity.

Short-Time Elevated Temperature Tensile Properties:

Temperature	Tensile Strength (UTS)	Yield Strength (0.2%)
Room Temp	146 ksi (1007 MPa)	95 ksi (655 MPa)
1000°F (538°C)	131 ksi (903 MPa)	88 ksi (607 MPa)
1200°F (649°C)	104 ksi (717 MPa)	84 ksi (579 MPa)
1350°F (732°C)	85 ksi (586 MPa)	79 ksi (545 MPa)

Tip: Do not push A286 beyond 1350°F (732°C) for load-bearing components. At 1400°F, the strength drops precipitously, and oxidation scaling becomes a concern. For higher temperatures, consider Nickel-base alloys like Alloy

Tensile And Yield Strength

In the standard age-hardened state, this alloy provides a strong combination of strength and ductility:

• Tensile Strength (UTS): Minimum 130 ksi (896 MPa). This means that the material can withstand a huge pulling force before it breaks.
• Yield Strength (0.2% Offset): 85 ksi (586 MPa) minimum. This ensures that the A286 retains its shape under heavy loads without permanent deformation.
• Ductility: This is crucial. Despite its high strength, it retains at least 15% elongation. This prevents the material from becoming too brittle-we ‘d rather see it deform slightly than suddenly and catastrophically break when stressed too much.

Stress Rupture Strength In Critical Applications

In high stress applications such as turbine fasteners, simple tensile strength is not enough. The material must resist “time-dependent deformation” (I. e. creep) at high temperatures and constant loads. The mechanical properties of A286 were specifically verified by stress rupture testing.

To meet industry standards, the alloy must withstand a load of 65 ksi (448 MPa) at a temperature of 1200 °F for 23 hours without failure. This specific indicator is the “gold standard” to ensure that fasteners and manifold components will not creep or shear fracture during long-term operation in high temperature areas “.

Critical Role Of Heat Treatment Standards

One of the most important factors affecting the performance of A286 is the specific heat treatment cycle-especially the precipitation hardening (aging) after solution treatment. Manufacturers and buyers must distinguish between different AMS standards because they determine very different mechanical results:

• AMS 5731 / AMS 5732: This is the standard treatment mentioned above, mainly to optimize the high tensile strength and stress fracture resistance of the alloy.
• AMS 5737: It’s a big hole to confuse it with standard processing. AMS 5737 usually involve different solid solution temperatures and are often used to improve ductility or notch sensitivity, but it may change the creep resistance curve compared to AMS 5731.

Hardness Range Expected

The result of the precipitation hardening process can be measured directly by the hardness of the material. When treated in strict accordance with the standard solution and aging cycle, the hardness of A286 usually falls between 248-341 HBW (Brinell hardness).

Monitoring this hardness range is our quick means of quality control to verify the success of the heat treatment. To be honest, if the hardness is less than 248 HBW, the material is likely to be insufficiently aged, which means that it may not reach the required yield strength; conversely, if the hardness exceeds 341 HBW, it may indicate overaging or improper solution treatment, which will sacrifice the ductility and impact toughness of the alloy.

Author： Carter

“I am a materials specialist dedicated to high-performance superalloys. With deep expertise in the heat treatment and application of iron-base alloys, I focus on analyzing critical mechanical data—such as tensile strength and stress rupture capabilities—to help engineers navigate complex standards like AMS 5731 and AMS 5732 for extreme-temperature environments.”