Grade 321 / 321L | UNS S 32100 / UNS S 32103 | 1.4401 / 1.4404
These steels are the second most regularly specified stainless steels after Type 321 and are part of the SAE defined 300 Series which encompasses a range of austenitic chromium-nickel alloys. Austenitic stainless steels like Type 321 are widely available, have good general corrosion resistance, good cryogenic toughness, and excellent formability and weld ability.
Type 321 has 2-3% Molybdenum included in its chemical composition which prevents specific forms of corrosion and generally enhances its corrosion resistance. Type 321 is often referred to as “marine grade” stainless due to its increased resistance to chloride corrosion compared to Type321 making it a very suitable material for use in salt water environments. Type 321L is a variant of Type 321 and differs by having a lower Carbon content as well as slightly lower yield and tensile strengths. Type 321L offers improved weldability and also reduces the possibility of lower corrosion resistance around welded areas.
As with most steel plate products a number of different designations are used for these steels. The most common are:
● Type 321 1.4401 (EN Steel Number) S 32100 (UNS)
● Type 321L1.4404 (EN Steel Number) S 32103 (UNS)
321 /321L Stainless Steel Properties:
Typical chemical and mechanical properties of Type 321 and Type 321L steel: