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Hard chrome plating corrodes in shipment by sea
Q. Cylinder piston rods which were hard chrome plated have rusted during shipment of our excavator. The equipment was shipped by sea and was on sail for nearly 2 months. We never faced such problem earlier. What could be the probable causes. Kindly guide as to the factors that we should examine.
Thanks,
B vishwas- Bangalore, Karnataka, India
2002
A. You say your machine was on a cargo ship for 2 months - that means it was exposed to the salt air for the same period (kind of like a real worldASTM B117 test). Chrome plating (even hard chrome) is pretty porous and if a product is going overseas, it should have a very strong corrosion inhibitor on it. I would recommend a waxy rust prevent that would create a heavy film on the part for protection. If that isn't possible, maybe wrapping the parts with a dessicant in the package might work.
Dan Brewerchemical process supplier - Gurnee, Illinois
2002
Q. Sir,
We are hard chrome platers, facing a problem of rusting on the whole rods when the rods get transited to Mexico from India through sea way. The rods get electroplated at 25 microns at the radius. Do we electroplate 50 microns at the radius so that the problem doesn't occur -- or any other views? Please advise.
- Delhi, India
March 29, 2012
April 5, 2012
Unless you own the design rights to the parts in question you cannot change the thickness of the plating without the permission of the design authority. Even if you do own the design I think that adding thickness will not solve your problem.
You need to look at how you protect the parts for sea transport. The use of a corrosion preventative is essential. In the UK we would normally treat with what is called a PX-1 or PX-4 corrosion preventative.
You may also look at the use of VCI/VPI type corrosion preventative papers. Ensuring you do not have intimate contact with wooden containers will also help, in fact use plastic containers if possible.
Aerospace - Yeovil, Somerset, UK
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