Mechanical Properties of Incoloy A-286 at Different Temperatures

(Detailed data of Incoloy A-286 mechanical properties in different temperature ranges. Reference for your material selection and design.)

When specifying fasteners, turbine casings, or load-bearing fixtures that must operate above 400°C, designers quickly discover that conventional austenitic stainless steels (304/316) suffer a sharp drop in yield and creep resistance. Incoloy A-286 (UNS S66286 / AISI Type 660 / W.Nr. 1.4980 / GH2132)—a precipitation-hardenable iron-nickel-chromium superalloy—is the industry benchmark for extended strength retention to 650°C (1200°F)​ in the aged condition. Its mechanical behavior across the cryogenic-to-elevated-temperature spectrum is therefore a critical reference for engineering design. Shanghai COCESS Special Alloys Co., Ltd​ supplies Incoloy A-286 bar, forging stock, plate, and precision-machined blanks in full compliance with ASTM A638 Grade 660 and AMS 5731–5737, supported by EN 10204 3.1 certification and technical data you can trust.

Metallurgical Basis for Temperature-Dependent Strength

Incoloy A-286 derives its strength from coherent γ′ precipitates [Ni₃(Al,Ti)]​ formed during aging (700–718°C × 16–18 h). This precipitation-hardening mechanism, combined with Mo solid-solution strengthening and B/V grain-boundary reinforcement, yields:

• High room-temperature tensile/yield values (Rm ≥ 895 MPa; Rp0.2 ≥ 585 MPa)

• Gradual, predictable strength decline with temperature rise

• Useful creep-rupture strength to ~650°C (limited by γ′ coarsening above ~700°C)

The alloy is solution treated + aged​ before mechanical testing. As-rolled or as-forged material notaged will show ~550–620 MPa tensile—insufficient for design use.

Chemical Composition (wt%, ASTM A638 Gr. 660 / AMS 5737)

Room Temperature Mechanical Properties (Solution Treated + Aged)

Elevated Temperature Tensile Properties (Typical, Aged Condition)

Data below represent typical trends for properly heat-treated material. Design allowables should be taken from qualified material specifications or ASME Section II Part D where applicable.

Key observations:

• Strength declines gradually; even at 650°C, yield strength remains > 480 MPa—far above 316 SS at same temperature.

• Ductility (elongation) is maintained well into the high-temperature regime.

• Long-term stressed service design limit is commonly 650°C max; above this, creep strain accumulates more rapidly as γ′ coarsens.

Creep & Stress-Rupture Reference Data (Typical Trends)

These values illustrate why A-286 is the preferred bolting alloy for steam turbines, gas turbine casings, and aerospace engine fasteners operating in the 425–650°C​ band.

<h3>Low Temperature (Cryogenic) Performance</hsh3>

A-286 retains excellent toughness and strength down to cryogenic temperatures:

• -196°C (77 K):​ Rm ≈ 1150–1280 MPa, A5 ≈ 25–35%, impact energy remains adequate—no ductile-to-brittle transition in the austenitic structure.

• Frequently used for cryogenic propulsion system fasteners in aerospace.

Elastic Modulus & Physical Constants vs. Temperature

Heat Treatment Required to Achieve These Properties

Material can be supplied solution annealed only​ (for customer to age after finish machining, avoiding distortion) or solution + aged.

Typical Applications by Temperature Regime

• Cryogenic to RT (−196 to 20°C):​ Aerospace propellant system fasteners

• RT to 425°C:​ General high-strength fasteners, lock pins, machine elements

• 425–650°C (primary design range):​ Gas turbine & steam turbine bolting, compressor case hardware, aircraft engine fasteners, heat-treat fixture load pins

• 705–760°C (unstressed / short-time only):​ Certain furnace components not under sustained high load