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Nickel Chrome plating ability due to pin hole

December 4, 2008

We have nickel chrome plating process for Motorcycle Front fork. The plating could not cover the pin hole. My question is does nickel chrome have the ability to plate at pin hole area? What kind of parameter are related to this issue and how do they work ?

The process before plating are seamwelding, pickling, cold rolled and CLG (center less grinding. Could you give me another perspective to find the root cause of pin hole defect? Our situation is pin hole defect is not from the raw materials because the fibers flow are bent not cut.
Best regards.

Edwin Muhammad
Analyst engineer - Jakarta, DKI Jakarta & Indonesia

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December 5, 2008

Hi, Edwin. I didn't understand the part about "fibers flow are bent", but nickel chrome plating will not fill a pinhole.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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December 11, 2008

Dear Sir,
We have pins hole with length 900 - 2000 µm, width 500 - 2000 µm and depth 40 - 300 µm. We investigated the metal flow by cut the pipe in axial direction so we can analyze the metal flow. At pin hole area the metal flow are bent not cutted that shows the metal flow was force in transversal direction.
We are trying now, to figure out the root cause of pin hole. The pipe comp are seamweld, then through the heat treatment and pre treatment (pickling) and cold roll.

Then the mother pipe will cut. And go through Center less grinding (60-70 µm feed) and Plating Ni-Chrome. The analysis still in progress. Now we are monitoring the cause of pin hole by each process.

If you have an experience about pin hole investigation would you kindly share to me? Is the cold roll become the most possible process that could cause pin hole?

Thanks

Muhammad Edwin
- Jakarta, Indonesia

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I'm having a little trouble picturing this. If you have a photomicrograph it would probably help.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 2, 2009