Passivation for Stainless Steel

Stainless Steel Passivation improves corrosive resistance and the durability of the material, especially in atmospheric corrosion. Despite its name, in case of exposer of stainless steel to salty atmosphere may cause formation of corrosion- though slowly than steel.

Passivation Process

Passivation for stainless steel is a chemical procedure that removes the iron from the surface of the stainless steel and is performed in the air. At the end of the passivation process a natural, transparent oxide is created from the oxygen in the air. This oxide provides the stainless steel with the necessary corrosion resistance.

Metal Finishing & Plastic LTD is certified by IAI to perform stainless steel passivation according to PS.

Standard QQ-P-35

Table according to Type
Solutions based on nitric acid compositions and at different temperatures

Type Solution Composition Temperature
Type 2 nitric acid based solution Moderate
Type 4 nitric acid based solution Low
Type 7 nitric acid based solution Moderate
Type 8 nitric acid based solution ?

Standard ASTM A 967

Recent standard which uses other nitrogenous solutions for nitric acid based solutions
Table according to Nitric

Nitric Solution Type
1 Solution based on nitric acid and supplements
2 Solution based on nitric acid at room temperature
3 Solution based on hot nitric acid
4 Solution based on hot nitric acid

Citric Acid Based Solutions
Table according to Citric

Citric Solution Composition Temperature Time
1 Citric Acid Based Solution High Short
2 Citric Acid Based Solution Moderate Medium
3 Citric Acid Based Solution Low Long
4 Citric Acid Based Solution or any other mixture that enables compliance with the Standard
5 Citric Acid Based Solution or any other mixture that enables compliance with the Standard according to defined acidity

IAI standard PS 23.1900

Classification according to Type

Type Solution Composition
2 nitric acid based solution and supplements
4 nitric acid based solution
8 nitric acid based solution

Classification according to Group

Group Stainless Steel Composition
1 Stainless Steel that contains more than 17% chrome (except 440C stainless steel)
2 Stainless Steel that contains less than 17% chrome

Aerospace Standard AMS 2700

Classification according to Type

Type Solution Composition Temperature
Type 1 nitric acid based solution Low
Type 2 nitric acid based solution Moderate
Type 3 nitric acid based solution high
Type 4 highly concentrated nitric acid solutions for processed steels
Type 5 Electric based passivation for steels that contain high carbon martensitic
Type 6 nitric acid based solution Low
Type 7 nitric acid based solution Moderate
Type 8 highly concentrated nitric acid solutions

Classification according to Method

Method Solution Basis
1 nitric acid based solution
2 nitric acid based solution

Classification according to Class

Class Testing frequency
1 Testing frequency according to demand
2 Testing of item per dose
3 Testing frequency according to period
Passivation for Stainless Steel
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