MIL-STD-870 Cadmium Plating, Low Embrittlement, ElectrodepositonThis 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 10 9 PASCALs Pa 240,000 pounds per square inch {psi} without the approval of the applicable procuring activity.

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MIL-STD-870C

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5.2.3   Storage of parts.   Storage of parts between stress relief and cleaning shall be controlled to prevent contact with water or other corrosive materials.  Parts shall be stored to permit free circulation of air around the parts.

5.2.4   Handling of parts.   After the parts have been cleaned, they shall be handled in such a manner (white gloves, etc.) that will ensure a minimum of contamination.

5.2.5   Masking.   Sections or areas of a part that are not to be plated shall be masked off.  Plugging and masking materials, which do not contaminate the plating bath, shall be used.  Masking shall be performed at the most convenient step prior to plating.

5.2.6   Racking.   Sufficient contact area and pressure shall be provided to carry the current without overheating.  Racking should be performed at the most convenient step prior to plating.

below:

5.3   Plating procedures.   The cadmium plating procedure shall be as described

5.3.1   Step Number 1.   Parts shall be degreased as necessary.  No minimum elapsed time requirement shall apply between this operation and the cleaning operation of Step Number 2.

5.3.2   Step Number 2.   All parts shall be cleaned by dry blasting using 80 - 320 grit aluminum oxide (Al203), silicon dioxide (Si02) or garnet per MlL-STD-1504.  Elapsed time between completion of cleaning and Step Number 3 shall not exceed four (4) hours.

5.3.3   Step Number 3.   Rinse parts in cold water.  A cyanide holding tank can be used to hold parts if the plating tank is full.

5.3.4   Step Number 4.   Cadmium plate at 5.4 to 7.5 amperes/sq decimeters (50

- 70 amperes/sq foot) in the following solution:

Cadmium metal                      21 - 30 g/l   (2.8 - 4.0 oz/gal) Total cyanide                          90 - 135 g/l   (12 - 18 oz/gal) Sodium hydroxide                  11.2 - 30 g/l   (1.5 - 4 oz/gal) Sodium carbonate                  0 - 60 g/l   (0 - 8 oz/gal)

Ratio NaCN/Cd                      4/1 to 6/1

Temperature                           15.5 - 26.6°C   (60 - 80°F) Total permissible iron             700 parts/million

5.3.5   Step Number 5.   Rinse parts in cold water.

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