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Black Oxide Coating Specification

Black Oxide Coating Specification

Black Oxide Coating Specification


                         I recently had a part coated with black oxide per AMS-2484-H.  My specification was to AMS-2485-C.  I cannot find a copy of the
                         revisions so I can determine what has changed from Revision C to Revision H.  Can anyone help?

RE: Black Oxide Coating Specification

I wouldn't worry about the rev. no., the problem is the difference between 2484 & 2485.  IMHO, the 2484 coating is much inferior -- it has less adhesion & under acidic exposure can give off noxious gas such as H2Se.
The 2484 coating that I am familiar with is CuSe (and/or Cu2Se) formed by immersion plating of Cu onto Fe in the presence of selenous acid. It is not an oxide, so if your P.O. specified 'Black Oxide,' and especially if you have a wear application, you should force a re-work at no charge.
The 2485 coating, 'hot black oxide,' is formed by oxidizing the surface in a concentrated, alkaline, oxidizing solution at ~290oF, and is extremely adherent.

From www.sae.org

"AMS2485 : Coating, Black Oxide 10-22-2002 Standard
 This specification covers the engineering requirements for producing black oxide coatings on parts and the properties of such coatings.
This coating has been used typically to improve the anti-chafing and anti-friction properties of carbon and low-alloy steel parts, particularly sliding or bearing surfaces, by providing a finish coating which will retain an oil film, but usage is not limited to such applications.
AMS2484 : Blackening Solution for Steel Touch-Up Method 07-01-2000 Standard
 This specification covers the requirements for an inorganic blackening solution for steel, applied at room temperature.
This blackening solution has been used typically for touch-up of black oxide surface finish in cases where the coating has been removed."

The same water-displacing oils and waxes can be applied to the latter finish, so it could be used for appearance sake & corrosion prevention in non-friction applications.

RE: Black Oxide Coating Specification

dear sir/madam,

after heat treatment welding of boron steels is possible?

if possible what is the welding electrode to be used which gives wear resisitance property also.


RE: Black Oxide Coating Specification

only people interested in black oxide coatings will see your post here. I suggest that you Start a New Thread in the Welding forum (in Structural Engineers) or the Metal and Metallurgy forum (in Materials Engineers).

Also, use an informative title, maybe
Welding of heat-treated B-steel?
Be sure to include all relevant info in your question, including the particular steel or steels you are interested in welding,  thickness, equipment available, post-welding heat treatment equipment available (yes/no), etc.

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