Zinc Plating Spec? 1

[amoncur]

Hi,

I would like to use a low or mild carbon steel for a part I am designing. The part is a cylinder. A low force (~2lbf) ball spring glides across the surface of the cylinder. I also need to prevent it from rusting. So, I would like to put a zinc coating on for corrosion resistance as well as strengthening the surface of the cylinder so the ball spring doesn't eventually wear grooves into it. On my print, how should I call out the zinc plating? Is there a standard that is typically used? What thickness is appropriate?

Thanks!

 

[amoncur]

I've done some more digging and it looks like a chrome plating will give me both a hard/wear resistant surface as well as excellent corrosion resistance. However, I see that an undercoat of copper or nickel is standard. Anyone know how thick the copper or nickel layer should be? This is for bonding strength, I assume? Is there a spec for the undercoat?

I'm also looking at using Al with a hard anodize, instead. Considering the load is only ~2lbf, any reason why the hard anodize might not work?

Would one be preferable over the other in terms of cost or effectiveness (effectiveness at wear resistance and corrosion, that is)?

 

[TVP]

At that load, a hard anodized Al surface should work fine. ASTM B 580 is the industry standard for such coatings, and I recommend specifying Type A (Engineering Hard Coat) with a thickness of ~ 25-30 micrometers. If you want to specify hard chromium (also called engineering or industrial chromium plating), then the standard is ASTM B 650. I recommend specifying a thickness of 10 micrometers minimum. Hard chromium plating does not require a copper strike, that is only used for decorative chromium layers.

 

[jbeckhou]

I would suggest a surface treatment using QPQ. It would be cheaper than ENP or Hard Chrome. Using QPQ would protect the whole part instead of just the ID.

Petrotrim Services

 

[boo1]

whats QPQ?

 

[jbeckhou]

http://en.wikipedia.org/wiki/Quench_polish_quench

http://www.durferrit.com/media/pdf/Tenifer_QPQ_eng.pdf

The links above will give you some info on QPQ process.

Petrotrim Services

 

[mrconfident]

I am in the Oil industry, we make equipment that is installed in an oil well. On our alloy steel parts, we call out the following:

Zinc plate, clear chromate @ thickness of .0002-.0004.