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Zinc plating of spring steel

February 25, 2008

We are going to be brake forming some .015" thick spring steel and then having it heat treated to attain the spring attributes (a spring constant of 5.5 lb/in), per the customer's requirements. After that, we are required to have the parts zinc plated .0003" thick per ASTM B633, Type III, SC 1, Clear.

My question is this: I believe that a hydrogen embitterment bake will be required after the plating -- will than anneal or in some way affect the material to such a degree that the spring properties will be affected?

Thank you.

David Maijala
quality manager - Los Angeles, California, USA

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No, David. Hydrogen embrittlement relief is done at 400 F or less.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 25, 2008

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February 27, 2008

Heat treated steel gets a "draw ' cycle in the oven after the heat hardening cycle to obtain the exact properties desired.
Typically, the 375 to 400 F bake will drop the RC by 1/2 to 1 point, which is not much for non critical parts.
It is possible to do a double draw at different temperatures to avoid the hardness reduction, but that costs money, so most do not do it.

James Watts
- Navarre, Florida

Thank you for your responses!

David Maijala
- Los Angeles, California, USA
February 29, 2008

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i want to know process of zinc plating on spring steel without including hydrogen. Which chemical is used for dehydration?

Thanks With Regards

K.P. SHARMA
- EARIDABAD/Hariyana/India
October 14, 2010

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Hi, K.P.

The hydrogen is removed by promptly baking at 375 to 400 °F, not by treating with chemicals. All zinc electroplating processes can cause hydrogen embrittlement. But it is possible to apply zinc by other means such as dip-spin coatings, mechanical plating, and hot-dip galvanizing that do not, per se, cause hydrogen embrittlement. But the preparatory steps for these processes, such as acid immersion or cathodic cleaning, may cause it.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 14, 2010