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Cracks in the chain after yellow zinc passivation

2006

Dear Sir,

We are a flexible coupling manufacturer in India. We manufacture various types of flexible couplings one of them is chain coupling. In the chain coupling we manufacture we use a 5/8" duplex chain.This chain is coated with yellow zinc passivation.

We have basically two problems:

No.1 - Before we plate the chain we have to clean the oil on the chain.We tried cleaning the chain in cyanide bath also in chromate bath but the complete chain does not get cleaned and if we keep the chain for longer time in the bath then the cracks develop. After few seconds of the plating of the chain cracks develop in the plates of the chain.

No.2 - To avoid the crack we do not wash the chain in the bath for longer time and go ahead with plating.But in the regions where the oil remains in the chain it does not get plated.

Can you please let us know what procedure should we follow to avoid both the above problems.

With regards,

Amit Y. Nangre

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Dear Mr. Amit,
You have not mentioned your cleaning process , you are doing only degreasing or any electrolytic cleaning? please mention that, do not use cyanide base chemicals for cleaning it is very much hazardous for humans.
Or you do cleaning of chains with diesel& kerosene 50/50% before going for chemical cleaning.

Vishwas Nangare
motorcycle accessories mfgr.
- Aurangabad, Maharashtra, India
2006

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Q. Hi I am having the same problem, the zinc starts cracking five minutes after plating process.

We don't do any electrolytic cleaning, do you have any suggestions?

Omar Reyes

June 19, 2012