EDELSTAHL SCHNEIDTECHNIK RHEIN-RUHR

Alloy 1.4878 /
AISI 321H

Austenitic steel alloy with excellent resistance to high temperatures and corrosion

1.4878, also known under the trade name X10CrAlSi25, is a high-alloy austenitic steel alloy, particularly valued for its excellent resistance to high temperatures and corrosion. It is widely used in applications requiring strong heat resistance and oxidation protection, such as in the energy and chemical industries, as well as in hot gas environments.

Chemical Composition (in %):

Element

Content

Chromium (Cr)

20,0 – 25,0 %

Aluminium (Al)

0,5 – 1,0 %

Silicon (Si)

1,5 – 2,5 %

Iron (Fe)

Balance

Nickel (Ni)

bis 1,0 %

Carbon (C)

bis 0,10 %

Manganese (Mn)

bis 2,0 %

Phosphorus (P)

bis 0,03 %

Sulfur (S)

bis 0,02 %

Properties:

Heat resistance:

  • Excellent oxidation and corrosion resistance at high temperatures up to approx. 1100 °C (2000 °F)
  • Chromium, aluminium, and silicon form a protective oxide layer against degradation in hot environments

Corrosion resistance:

  • Good resistance to many aggressive chemicals, especially oxidizing media
  • Aluminium addition forms a stable protective alumina layer at high temperatures

Mechanical properties:

  • Retains strength and toughness at high temperatures, with stable performance even near melting point

Resistance to thermal expansion:

  • Low thermal expansion, suitable for applications requiring dimensional stability under heat loads

Weldability and machinability:

  • Generally weldable with specific treatment required for optimal corrosion resistance and strength
  • Machining requires specialized equipment due to hardness from high-temperature resistance

Applications:

  • Hot gas environments: Used in turbines, combustion chambers, and exhaust systems exposed to high temperatures and aggressive gases.
  • Power generation: Applied in boilers, heat exchangers, and other high-temperature components in power plants.
  • Chemical industry: Used for reactors, furnaces, steam generators, and high-temperature vessels exposed to corrosive conditions.
  • High-temperature treatment plants: Employed in processes such as metal heat treatment and glass production.

Conclusion:

1.4878 is a high-alloy austenitic steel with excellent resistance to high temperatures and aggressive chemical environments. It is widely used in energy production, chemical processing, and high-temperature applications where oxidation resistance is critical. Its strong mechanical properties at high temperatures and good corrosion resistance make it a preferred choice for demanding industrial applications.

Note: The information in this datasheet is provided for description purposes only; no liability is assumed!