Metallographic diagram of Ineoloy800 (cold-rolled and annealed after solid solution)

INCONEL® alloy 800 is an austenitic nickel-chromium alloy with a controlled carbon content. It is particularly useful for its excellent resistance to carburization and oxidation. Alloy 800 also has a very good strength and excellent resistance to stress rupture and creep. It resists nitridation and is used for many industrial applications such as turbines, furnaces, and steam generators.

When it comes to its microstructure, INCONEL® alloy 800 is composed primarily of austenite. It is a solid solution alloy containing iron, chromium, nickel, and some other minor elements. The iron content of alloy 800 is typically between 75 and 85 weight percent, while the chromium content is typically between 16 and 26 weight percent, depending on its grade. The other minor elements can include up to 2 percent manganese, up to 2 percent aluminum, and up to 6 percent titanium.

After recrystallization and cold-working, INCONEL® alloy 800 typically develops a fine, equi-axed grain structure. However, grain size can be altered by changing the heat treating process and parameters. In general, the grain size of the alloy increases with increasing cold-working and then decreases with increasing temperature. This is because the grain growth is both promotion of recrystallization and dissolution of Zener pinning.

A metallurgical analysis done on INCONEL® alloy 800 will reveal a number of visible features including lath-like austenite grains and needle-like ferrite grains. The grains are typically elongated and have a ductile nature. At the grain boundaries, one can observe a flaky ferrite-austenite-iron carbide precipitate, an example of the complex microstructure of the alloy. Other features at the grain boundaries include fine, stellite-like precipitates and occasional segregations.

If a metallographic analysis of INCONEL® alloy 800 is conducted, then the material should have a duplex grain texture of equi-axed grain structure. This texture is typically best defined in the prior austenitic cold-worked condition. The matrix features should consist of fine, evenly distributed MC carbides and intergranular chromium-depleted ferrite. The carbide precipitates and carbide film should generally be absent.

INCONEL® alloy 800 is a reliable and highly corrosion-resistant material that has many uses in the industry. Its microstructure consists of a duplex grain texture of equi-axed grain structure, with a lath-like austenite grains, needle-like ferrite grains and an intergranular chromium-depleted ferrite that is visible when examined under a metallurgical analysis. This complex grain texture gives the alloy its excellent properties, such as resistance to carburization, oxidation, and stress rupture.

Inconel 800 is an alloy of nickel, chromium and iron that offers high-temperature strength and corrosion resistance. It is often used in high-temperature applications, such as turbine blades and recuperators in aircraft engines and industrial furnaces.

Inconel 800 is a nickel-chromium alloy characterized by high-temperature strength and excellent corrosion resistance at elevated temperatures up to 1000°F (537°C). Its high chromium content provides excellent resistance to oxidation and carburization in environments up to 1700°F (927°C). The combination of these properties make Inconel 800 ideal for use in high-temperature applications, such as gas and steam turbine components.

Inconel 800 has a ferritic face-centered cubic (FCC) lattice structure that is resistant to rapid diffusion of elements due to its low alloying content. This makes it suitable for forging, rolling, and extruding operations. Once Inconel 800 is cold rolled and annealed, its excellent ductility, strength, and hardness make it an ideal material for springs, fasteners, and other components where mechanical properties are important.

Inconel 800 is available in a variety of forms, including wire, bar, and plate. It can be machined with conventional tools, but it is more commonly cold-worked and/or hot-formed as it has excellent hot working properties. Inconel 800 can be welded using a range of techniques, but the most common are gas tungsten arc welding (GTAW), shielded metal arc welding (SMAW), and gas metal arc welding (GMAW).

Due to its beneficial properties, Inconel 800 is extensively used in a variety of industries, including aerospace, energy production, petrochemical and marine. Its superior thermal fatigue strength allows it to be used to fabricate the most heavily-stressed components, such as turbine blades and casing, and its resistance to oxidation and carburization make it ideal for industrial furnace components.