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Rust in Custom Tubes for Volvo parts

Hello everyone,

I hope someone can help me figure out how to keep moisture from getting inside our tubes which causes a rust problem w/in a months time. We have a plating system here at the plant that goes through a degreaser tank then to an acid then a rinse then a zinc bath then to the chromate dip which then a rust inhibitor dip then to a wax then to a dryer. When all said and done no rust in parts. once moved from the plater it is put into our racks for stock and sits there until we use them which could be the next day or a year. Most parts tend to rust within a month. any solutions to prevent this from happening?

Joe Steven Niyery
plating company - Compton, Ohio, United States
2005

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There can be several causes for the problem you are having. First are the parts dry on the inside before they are removed from plating? If not, a manual air blow down may be beneficial. Next, corrosion inside would be caused by having a chemically active surface. Since you are coating with what I assume is a "water based" wax, the corrosion must be taking place under the wax, therefore a rinsing problem would be the key. I would look at the rinse after chromating and before the rust inhibitor. Also check with your supplier (speak with a technical person in the support lab) and find out if the rust preventative is compatible with the wax and if one does not negate the other.

I also need to point out the most obvious, is corrosion on the inside of the tube before plating or occurring during the preplate cycle?

Gene Packman
process supplier - Great Neck, New York
2005

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2005

Joe, How thick is the zinc deposit inside, use a help anode to get a better zinc deposit inside the tube.

Regards,

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden

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2005

Hello Mr Joe Stevens,

Since your customer does not want plating inside the tubes it is advisable to plug them up well before plating so that the inner surface does not contact any cleaning or plating soulution at any time. This way the tubes last much longer than if they were cleaned and coated again.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India