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Alloy 321

An austenitic Chromium-Nickel-Titanium stainless steel, Alloy 321 offers outstanding performance at temperatures up to 870°C.

Whilst retaining good strength and corrosion resistance when exposed to high temperatures, Alloy 321 will also maintain its strength and toughness at sub-zero temperatures.


Product formsSize range fromsize range to
Alloy 321 round bar9.53 mm184.15 mm GET A QUOTE
Alloy 321 sheet & plate0.4064 mm20 mm GET A QUOTE

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Round Bar

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Sheet & Plate

Chemical Analysis

Min179--5x (C+N)--0.25----


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Perfect for applications in the Thermal Processing industry

Alloy 321 can be used in a variety of applications, here are just a few examples:

  • Aircraft piston engine manifolds
  • Expansion joints
  • Thermal oxidizers
  • Refinery equipment
  • High temperature chemical process equipment

About Alloy 321

Alloy 321 stainless is a Titanium stabilised grade commonly used for service in the 538 – 870°C temperature range. For service temperatures up to about 870°C, a stabilising treatment at 842 – 899°C air cool, may be used to provide optimum resistance to intergranular corrosion in the heat affected zone (HAZ) and to polythionic acid stress corrosion cracking.

Alloy 321 stainless is readily welded by all common methods including submerged arc. Appropriate weld fillers are AWS ER347 bare wire and E347 covered electrodes. Alloy 321 stainless is good machinability and is readily fabricated.

For more information on Alloy 321 Stainless contact us, or fill in our online quote form and we’ll get right back to you!


7.916 g/cm³
Melting range:
1400 –1427°C


UNS Number:
UNS S32100
ASTM A240, A276, A312, A479, AMS 5510, 5645
Download the Alloy 321 Data Sheet Download

FAQs & Resources

Alloy 321 is a Titanium stabilised austenitic stainless steel with an addition of Silicon and a nominal Chromium and Nickel content of 18% and 11% respectively.
The addition of Titanium stabilises the formation of Chromium carbides and gives the alloy excellent resistance to intergranular corrosion after exposure to temperatures in the Chromium carbide precipitation range of 427°C - 816°C.

Corrosion resistant alloys rely on the existence and stability of a Chromium oxide passive film on its surface to act as a protective barrier against deleterious interactions between the environment and component.

  • Oxidation resistance to 870°C
  • Higher creep & stress rupture properties than conventional stainless grades i.e. 304, combined with good low temperature toughness
  • Good general corrosion resistance particularly in the Chromium carbide precipitation range of 427°C to 816°C where conventional stainless grades will fail due to intergranular attack
  • Suitable for use in the most dilute organic acids at moderate temperatures, pure phosphoric acid at lower temperatures and up to 10% concentration
  • Resistance to polythionic stress corrosion cracking in hydrocarbon environments
  • Not suitable for use in chloride solutions even in low concentrations, or in Sulphuric acid service
  • Aerospace piton engine manifolds
  • Expansion joints
  • Petroleum refining - Polythionic acid service
  • Waste treatment - Thermal oxidisers
  • High temperature chemical process plant

Request a Quote

Fill in our online form to get a fast quote. Got a technical question? Contact us on techsales@neonickel.com or for more general enquiries please email us at enquiries@neonickel.com