Rusted Chrome Copper

[picksbendy]

Hi guys,
I'm facing a big problem which i've never come across or expected. Hope that could get some FAQs and advise.
I'm having a batch of faucet(with nuts together as an assembly)rusted when put in water. Tested for around 2 hours and rust could be seen on nuts and threaded area of faucet.
Anyone having any idea what's causing that? never have such problem previously.
Has it got to do with poor chroming process? Can i send it to be chromed again?

 

[EdStainless]

This is Cr platted brass?
You need to identify which part is corroding.
It could be related to the surface preparation or to bad Cr.

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Plymouth Tube

 

[picksbendy]

Hi EdStainless,
I am suspecting it is due to bad chroming, i tried to sand off the rust and test it in water again, the rust doesn't come back. Because it is Hex nut, hard to sand the whole surfaces, is there any solution can be tested to clean the entire surface of the chromed part?