Passivation of Stainless Steel to ASTM A967. Five nitric and citric methods are listed as follows: Nitric 1: 20-25 v% Nitric Acid, 2.5 w% Sodium Dichromate, 120-130F, 20 Mins minimum. Nitric 2: 20-45 v% Nitric Acid, 70-90F, 30 Mins minimum. Nitric 3: 20-25 v% Nitric Acid, 120-140F, 20 Mins minimum. Nitric 4: 45-55 v% Nitric Acid, 120-130F, 30
A 967 2 3. Terminology 3.1 Definition of Term Specific to This Standard—It is necessary to define which of the several commonly used definitions of the term passivation will be used in this specification.(See Discussion.) 3.1.1 Discussion—Stainless steels are autopassivating in the sense that the protective passive film is formed spontaneously
Scope. 1.1 This specification covers several different types of chemical passivation treatments for stainless steel parts. It includes recommendations and precautions for descaling, cleaning, and passivation of stainless steel parts. It includes several alternative tests, with acceptance criteria, for confirmation of effectiveness of such
ASTM A967-2001 . This standard is issued under the fixed designation A 967; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript