Salt Spray Correlation to Plating Thickness

[bebogie]

Our specification to white rust in salt spray is 96 hours using ASTM B201 & B117. Is there a correlation to plating thickness? Does process differences between plating contractors have an impact on the thickness?

We recently changed plating contractors. Materials is requesting a plating thickness specification. I'm not sure this is the correct approach vs a performance spec...

Regards,
Bruce

 

[TVP]

Corrosion resistance in terms of formation of red rust is directly related to the thickness of the zinc plating, as well as the type of chromate, sealer, etc. The number of salt spray hours until the formation of white rust is dependent upon the type of chromate coating, its quality, and whether or not a subsequent seal or topcoat is used. Chromates are rarely specified in terms of thickness, but the zinc plating almost always is.