×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Black Oxide a 300-series stainless?

Black Oxide a 300-series stainless?

Black Oxide a 300-series stainless?

(OP)
I just saw this on a drawing and admittedly have never seen it before and don't understand why they would bother with the expense of the extra process, short of pretty color.

Material: 302 or 304 Stainless
Finish: Passivate per QQ-P-35, Type VI or VII.  Black Oxide per MIL-C-13924, Class 4.

It may just be my experience with stainless steels, but I have only ever used Black Oxide on plain carbon steels and tool steels, not stainless.  And why do I need the extra corrosion inhibiting oxide layer of the black oxide process after I have passivated it?  Doesn't that defeat the purpose of the passivate?

--Scott

http://wertel.eng.pro

RE: Black Oxide a 300-series stainless?

The only reason to create the black layer is for appearance or optical/thermal properties, not for corrosion resistance.

Regards,

Cory

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.

RE: Black Oxide a 300-series stainless?

We have done it on 17-7 stainless springs used in a military application.Other than that, it makes no sense.

RE: Black Oxide a 300-series stainless?

(OP)
CoryPad guessed it.  Why it didn't occur to me until I read his statement regarding "optical properties" I don't know.  

The component is on an exposed part of the product that can not be shiny or reflective.  Black Oxide allows for functionality of the part, where painting would not, and gets rid of the reflectivity of that particular component.

--Scott

http://wertel.eng.pro

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources