Equivalent Cadmium Plating Specification

[MNLiaison]

I have a component made from 4140 steel heat treated to 180 - 200 ksi that calls for cad plating per Douglas Process Specification (DPS) 9.28 "Special Cadmium Plating For High Strength Steels".

Does anyone know of an "equivalent" AMS, SAE, MIL, or NAS specification in lieu of the original DPS 9.28?

I do not believe that QQ-P-416 is an equivalent process.

Regards

 

[der8110]

What has made you think QQ-P-416 is NOT an equivalent process? It does have provisions for 160-200 ksi steels (hydrogen embrittlement relief). You should be fine as long as the baking step is followed.

AMS2401 is probably what you are looking for - cad plating of high strength steels, 180 ksi and above.

 

[ERAU82]

Does the part have any threads? My experience with landing gear parts in this heat treat range is to use LHE Cadmium plating (Low Embrittlement). It is used mainly on parts heat treated 220-300 Ksi and threaded parts treated to 180-220 Ksi. The spec is AMS2401 or MIL-STD-870.

If you are manufacturing and not restricted to a set process as may be the case with repairing to OEM specs, the move is to go away from the heavy metal type plating (cadmium, chromium) due to health and environmental issues and the tighter regulations on their use. You may want to look at Sn-Zn, Zn-Ni, or electroless Ni as they are good alternatives but you need to know the working environment of the part to get the best results.

SAE's website has several articles on replacments for cadmium plating.

Regards,

 

[israelkk]

MIL-STD-870C CADMIUM PLATING, LOW EMBRITTLEMENT, ELECTRODEPOSITON

1.1 Scope. This standard covers the process and materials required for the electro-deposition of cadmium on high strength steel substrates. Subsequent heat treating techniques needed to insure low embrittlement of steel are also described. This process is not authorized for use on steel heat treated above 1.65 X 109 PASCAL’s (Pa) (240,000 pounds per square inch {psi}) without the approval of the applicable procuring activity

1.2 Documentation. This standard meets the corrosion resistance requirements of SAE-AMS-QQ-P-416. It may be used whenever SAE-AMS-QQ-P-416 is specified provided any unique requirements in SAE-AMS-QQ-P-416 are compiled with.

Another even safer is MIL-C-8837B COATING, CADMIUM (VACUUM DEPOSITED) (S/S BY SAE-AMS-C-8837)

 

[MNLiaison]

Thanks to everyone for replying. I have reviewed all the specifications listed and have made my decision to stick with the original DPS call out. We had two plating vendors lined up and only one of them was able to plate to the DPS but they charged a little more. The other vendor could follow a "public" specification ....... hence my question.

Thanks again.

 

[yates]

I believe the Douglas spec. you are looking for concerns low-embtittlement cad. plating by the fluoborate process. The process is described in NAS672. You may have somme difficulty finding someone to perform the process for you. It may be easier for you to get the part vacuum cad. plated (MIL C 8837)