321 / 321H Stainless Steel

Grade 321 / 321H | UNS S32100 / UNS S32109 | 1.454 / 1.4878

Characterised by its good oxidation resistance up to 1600F and its superior resistance to polythionic stress corrosion cracking 321 Stainless is an alloy that offers outstanding performance at a competitive price.

Alloy 321 stainless is a titanium stabilized grade commonly used for service in the 1000-1600°F temperature range.

For service temperatures up to about 1600°F, a stabilizing treatment at 1550-1650°F, air cool, may be used to provide optimum resistance to intergranular corrosion and to polythionic acid stress corrosion cracking. 321 stainless is readily welded by all common methods including submerged arc. Appropriate weld fillers are AWS ER347 bare wire and E347 covered electrodes.

321 stainless is similar in machinability to 304 stainless steel. It has a machinability rating of 45% relative to AISI B1112.

Features of Alloy 321
◾Oxidation resistant to 1600°F
◾Stabilized against weld heat affected zone (HAZ) intergranular corrosion
◾Resists polythionic acid stress corrosion cracking

As with most steel plate products a number of different designations are used for these steels. The most common are:
•Type 321 1.4541 (EN Steel Number) S32100 (UNS)
•Type 321H 1.4878 (EN Steel Number) S32109 (UNS)


Typical industrial sectors:

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