Unsensitized austenitic stainless steels (that is,
solution-annealed material containing no carbides
or other deleterious phases) are subject to
intergranular corrosion in very highly oxidizing
environments, such as HNO3 containing hexavalent
chromium (Ref 20). None of the regularly
controlled metallurgical variables influences this
type of intergranular attack. Additional information
on, and micrographs of, s phase in austenitic
stainless steels can be found in Ref 21.