What Is Incoloy 825

Incoloy 825, also known as 0Cr21Ni42Mo3Cu2Ti in China

We introduced Incoloy 800 (UNS N08800) yesterday, so let’s learn about the same series of 825 today.

Incoloy 825 tubes

It is a Ni-Fe-Cr-Mo-Cu corrosion resistant alloy stabilized with titanium. It is called Incoloy 825 abroad, also known as Ni-O-nel 825 or Ni-O-nel alloy. The Chinese national standard is GB NS142.

Incoloy 825 has good general corrosion and local corrosion resistance and good process performance. Therefore, it has been widely used in the chemical, energy, petrochemical, and hydrometallurgical industries.

The balance between the nickel content and the chromium content in the alloy composition determines the pure austenite structure of the alloy in the solid solution state. However, during medium-temperature aging, carbides and intermetallic compounds will precipitate on the austenite matrix and intergranular. These precipitated phases will harm the mechanical properties and corrosion resistance of the alloy.

Corrosion resistance of Incoloy 825

  • 1). This alloy is resistant to atmospheric corrosion in industrial and marine environments, but in an atmosphere with high chloride content, especially in a humid atmosphere, this alloy will produce very shallow pitting corrosion.
  • 2). Fresh water corrosion resistance, including the most corrosive compounds containing free CO, iron and chloride, natural water and various industrial cooling water containing impurities, the corrosion rate is usually less than 0.0025mm/a.
  • 3). Strong corrosion resistance in high-speed seawater, but certain corrosion will occur in static and low-speed seawater or under polluted seawater conditions.
  • 4). It can be used normally in hydrochloric acid and sulfurous acid solution at room temperature, but not in gasified hydrochloric acid. This is because the alloy has poor corrosion resistance in hydrofluoric acid.

Features and Application areas

It has good stress corrosion cracking resistance, pitting corrosion and crevice corrosion resistance, good oxidation resistance and non-oxidizing thermal acid performance, and has good mechanical properties at room temperature and high temperatures up to 550°C.

Generally used in the following fields:

Due to the wide corrosion resistance of this alloy, it is widely used in chemical processing industry, hot sea water and hydrometallurgical plants.

It is mainly used for heat exchangers, pipes, valves, pumps, etc. in the treatment of hot sulfuric acid, chloride-containing solutions, sulfurous acid and other environments. It is also widely used in the field of wood pulp extractor and deep source gas well in the paper industry.


Posted by KAYSUNS, the stainless steel pipe fittings supplier.

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