USN S32100321 SS is a heat resistant steel containing titanium to form a carbide of low solid solubility for a reduced possibility of inter granular precipitation and of associated inter granular corrosion. 321 SS exhibits a high degree of resistance to corrosion and oxidation while possessing high creep strength. Type 321 is primarily used for welded construction and for parts intermittently heated within 900-1600°F. 321 SS is nonmagnetic when annealed, and slightly magnetic when cold worked.
Composition [Cr 17-19%, Ni 9-12%, Ti 5xC min., C 0.08 max.] Specifications ASTM A580, AMS 5689