INCOLOY A-286
Incoloy A-286: A Superalloy Providing High-Temperature Strength and Corrosion Resistance
In today’s demanding industrial environments, the alloys used in applications requiring high-temperature strength, mechanical strength and corrosion resistance are opening the way for technological progress. In this context Incoloy A-286 is among the superalloys that stand out, taking on critical duties particularly in the aerospace, energy, automotive and chemical sectors. This article covers the chemical and mechanical properties of Incoloy A-286, its AMS and ASTM standards, its production processes and its fields of application in detail.
Chemical Composition and Microstructure of Incoloy A-286
Incoloy A-286 is a nickel-based iron–nickel–chromium superalloy. Its chemical composition is generally;
- 24–26% chromium (Cr)
- 13–16% nickel (Ni)
- 1–2% molybdenum (Mo)
- 1–2% titanium (Ti)
- 1–2% aluminium (Al)
- 0.10% carbon (C)
- 0.5% iron (Fe) and trace elements
With its precipitation hardening structure, this alloy provides excellent mechanical strength and corrosion resistance even at high temperatures. Its microstructure contains, alongside the austenitic phase, the intermetallic particles formed by precipitation hardening. These properties are an important advantage separating Incoloy A-286 from the other austenitic alloys.
Incoloy A-286 Mechanical and Heat Treatment Properties
The mechanical properties of Incoloy A-286 are optimised by suitable heat treatments. Its typical mechanical properties are:
- Tensile strength: 950–1250 MPa (depending on the heat treatment)
- Yield strength: 690–1100 MPa
- Hardness: 300–380 HB
- Elongation: between 15 and 30%
Heat treatment is generally carried out for precipitation hardening and includes the following steps:
- Solution annealing of the alloy at 1038–1065 °C
- Rapid cooling
- Ageing (tempering) between 730 and 760 °C
Thanks to this heat treatment, the strength and corrosion resistance of the material at high temperatures increase considerably.
Incoloy A-286 AMS and ASTM Standards
Since Incoloy A-286 is a critical material used particularly in the aerospace and defence industries, it is tightly regulated by AMS and ASTM standards:
- AMS 5731: the comprehensive standard for Incoloy A-286 forged products. It details the chemical composition, mechanical tests, hardness and heat treatment conditions.
- AMS 5737: specifications for Incoloy A-286 bar and wire products.
- AMS 5382: sheet and plate standards for Incoloy A-286.
- ASTM B637: the comprehensive standard setting out forging and heat treatment conditions for superalloys and austenitic steels.
These standards allow the manufacturer to guarantee material quality and ensure that the product gains international acceptance.
Incoloy A-286 Technical Properties and Specifications
Alongside its chemical composition and mechanical properties, Incoloy A-286 is known for its resistance to corrosion, oxidation and thermal fatigue at high temperatures. Commercially it is also defined by the code “UNS S66286”.
In particular;
long-term use at temperatures up to 650 °C
high oxidation resistance
durability in aggressive environments such as sulphur and chlorides
are the properties that make it the preferred choice in special and critical applications.
Industrial Applications
Incoloy A-286 is used in a wide variety of applications requiring high performance:
- Aerospace: the hot sections of jet engines, turbine discs, compressor shafts
- Power generation: gas turbines, nuclear reactor equipment
- Petrochemicals: valve, pump and piping elements in high-temperature and corrosive environments
- Automotive: turbocharger components, exhaust systems
- Medical devices: implants and surgical instruments requiring high strength
Its high-temperature performance and durability make Incoloy A-286 indispensable in many critical applications.
Incoloy A-286 Production and Machinability
The production of Incoloy A-286 involves complex processes such as heat treatment and forging. Its machinability is moderate; precision machining is possible with suitable cutting tools and cooling techniques. Although its weldability is limited, weld quality is improved by applying special techniques.
Tempering after heat treatment increases the toughness of the material and prevents crack formation. For that reason, strict adherence to the heat treatment protocols is maintained in the production of critical parts.
Advantages
- High-temperature strength and long-term stable performance
- Superior corrosion and oxidation resistance
- A good balance of mechanical strength and toughness
- Properties that can be optimised by precipitation hardening
- A high quality guarantee through conformity with AMS and ASTM standards
- Reliability in critical aerospace and energy applications
Disadvantages
- Its machinability is difficult compared with some other alloys
- Welding operations require special knowledge and equipment
- High cost, a disadvantage especially in small-scale production
- Long heat treatment times and complex production requirements
- It can show sensitivity in some chemical environments (for example high chloride concentrations)
Conclusion
Incoloy A-286 holds a critical place among the superalloys that perform superbly at high temperature and in demanding environmental conditions. Strict quality control and certification processes under the AMS and ASTM standards allow this alloy to be used with confidence in fields such as aerospace, energy, automotive and petrochemicals. Requiring expertise in production, heat treatment and machining, Incoloy A-286 is an indispensable material for industrial users seeking durability and reliability over the long term.
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| Chemical Composition (Incoloy A286) | Mechanical Properties at Room Temperature | | |
|---|---|---|---|
| Grade | A286 (UNS S66286) | Properties | Values |
| Ni | 24-27% | Density (Specific Gravity) | 7940 kg/m³ |
| Cr | 13.5-16.0% | Melting Point | 1370 – 1430 °C |
| Fe | 49-59.5% | Specific Heat | 419 J/kg•°C |
| Mo | 1.0-1.5% | | |
| V | max 0.10-0.50% | | |
| B | max 0.001-0.010% | | |
| C | max 0.08% | | |
| Mn | max 2.00% | | |
| Si | max 1.00% | | |
| S | max 0.03% | | |
| Al | max 0.35% | | |
| Ti | 1.90-2.35% | |
We supply this material
Incoloy A286 (1.4980 / UNS S66286) is supplied in bar, plate and wire form, certified to AMS 5732, AMS 5737 and AMS 5731.
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