Comparison of Inconel 718 and A286 and their importance in jet engines

A286 alloy:

• An age-hardenable iron-based alloy with high strength and excellent processing properties.

• The ability to maintain stable strength and oxidation resistance at temperatures exceeding 1500°F (about 815°C) makes it a major component in aircraft gas turbine engines.

• Specifications for A286 include AMS 5731, AMS 5732, AMS 5734, AMS 5737, AMS 5853, AMS 5726, and UNS S66286.

Inconel 718 alloy:

• A nickel-chromium alloy that is precipitation hardenable and has creep rupture strength at high temperatures up to 1300°F (about 700°C), also ideal for turbine engines.

• Known for its corrosion resistance, high strength, and excellent weldability.

• Specifications for Inconel 718 include AMS 5589, AMS 5590, AMS 5662, AMS 5663, AMS 5664, and AMS 5962.

Importance in Jet Engines

• The materials in jet engines are subjected to extreme conditions, with turbine blades having walls about 1mm thick and rotational speeds up to 10,000 revolutions per minute, so the alloys used must be able to withstand extremely high temperatures from the different gases.

• The similar properties of Inconel 718 and A286 allow them to both perform well in demanding environments like jet engines, allowing the engines to operate at higher temperatures.

• Operating jet engines at higher temperatures reduces fuel consumption and increases gas pressures, which directly contributes to reducing emissions from air travel.

In-depth Analysis

• A286 has excellent corrosion resistance up to 1300°F (about 700°C), making it well suited to operating in the wide range of atmospheres encountered in jet engine service.

• Inconel 718 is unique in that it allows for age hardening, which allows it to be welded without spontaneous hardening during heating or cooling.

• As an iron-based alloy, A286 is easier to machine than nickel-based hardening grades like Inconel 718.

• The melting point of Inconel 718 is 2437°F (about 1337°C), while A286 has a slightly higher melting point of 2460°F (about 1355°C).

Application Differences

• Inconel 718 is commonly used as a turbine disk material in jet engines due to its high quality weldability.

• A286 has its specific use in aircraft turbine engines due to its easier and more efficient machining.