Aloha, fun & authoritative answers -- no cost, no registration, no passwords, no popups
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Home /
Site 🔍
pub  Where the
world gathers for metal finishing
Q&As since 1989


ASTM A967 spec says passivate it, but AMS2759/8 note says depassivate it

Q. I have once again come across an old drawing that calls out two conflicting finishing notes. One note says to passivate per ASTM A967 and a note further down the drawing says to ion nitride per AMS2759/8 60-65 HRC with a finished case depth of .0025-.0030 on each surface. (Note: De--passivate all parts prior to nitriding).

I am not a finishing expert, but it is confusing when a drawing says to passivate then depassivate for ion nitriding!
I am guessing that I can get rid of the ASTM A967 note & just go with the ion nitride note for finishing. Can these two processes co-exist? Is there a need to?

Denny Falls
engineering - Woodland Park, Colorado, USA

A. Denny

If I recall correctly, nitrided surfaces should not be subjected to passivating solutions, and be performed after passivation. I believe the 'de-passivation' refers to the areas to receive the nitriding- "....0025-.0030 on each surface".

If the entire part is to be nitrided, then the initial passivation ensures an iron free surface to apply the nitride to, after de-passivation.

Willie Alexander
- Colorado Springs, Colorado

Q. Willie,
Thanks for the input, but I am still confused. Let us set up a scenario. You have a piece of Stainless machined to print. You (usually) send the part out for finishing work. It reaches the finishing company, they passivate the part then turn around and de-passivate the part for ion nitriding. Is that how it is done? Do finishing companies passivate then de-passivate for ion nitriding even if you don't call it out on the drawing? Do you have to perform the pass/depass steps to get an SAE-AMS2759/8" --> finish? (p.s. the whole part is being ion nitrided)

Denny Falls
Engineering - Woodland Park, Colorado, USA

none is made possible by supporting advertisers ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
Consult'g, Train'g
& Software

About/Contact  -  Privacy Policy  -  ©1995-2024, Pine Beach, New Jersey, USA  -  about "affil links"