Metal finishing Q&As since 1989

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Testing for Passivation of Stainless Steel

adv.   

Q. Hi dear,
I have conducted specimen tests on the passivation process for qualification. Before I did the humidity test, I first did the copper sulfate test to make sure that the specimens were really iron free.
The results of the copper test did not show any free iron, but the results of the humidity test of some specimens showed the presence of free iron. I have controlled for possible contamination in the environment, but the results are still unsatisfactory. Is there anyone who can help me?

Sugiarto Adi
- Jakarta, Indonesia
April 29, 2024

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Q. We have passivated SS-316L parts based on the SAE format -AMSQQP35 [canceled] (Type VI). For testing the passivation, it has been suggested SALT SPRAY TEST, copper sulphate [on eBay or Amazon]TEST, HUMIDITY TEST & Water immersion test. What type of Salt Spray test should we perform on this passivation and for what duration?

SHARAT FAQURUDHEEN
- Chennai, Tamil Nadu, India
2003

A. Dear Mr Sharat,

You may suggest a neutral Salt Spray test for 48 hours, as per procedure specified in IS 9844 or ASTM B117.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

A. You wrote:We have passivated SS-316L parts based on the SAE format AMSQQP35 (Type VI). For testing the passivation, it has been suggested SALT SPRAY TEST, copper sulphate TEST, HUMIDITY TEST & Water immersion test. What type of Salt Spray test should we perform on this passivation and for what duration?

Para. 4.4.1 of AMSQQP35 specifies that either a water immersion test or a high humidity test be performed to verify effectiveness of passivate process. You must perform this test to be in compliance with the specification unless:

Procuring activity allows either a copper sulphate test per Par. 4.4.2.2 of AMSQQP35 or a salt spray test per Para. 4.4.2.1 of AMSQQP35. The copper sulphate test is the easiest to perform. When salt spray test is performed AMSQQP35 states that it shall be in accordance with ASTM B117 and performed for a minimum of 2 hours using a 5% salt solution.

Peter Cox, Quality Manager
- Seabrook, New Hampshire USA