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Guest amoncur

Chrome Plating Question

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Guest amoncur

I would like to provide a wear and corrosion resistant coating to an inexpensive steel substrate. The part will be visible to the user (consumer product) and so I would like the coating to have an appealing finish. For this reason I have chosen chrome plating. Can anyone confirm this would be an appropriate plating note to include on my drawing?

 

CHROME PLATE. REFERENCE QQ-C-320 TYPE 2 CLASS 2

 

My understanding is this instructs for a satin finish engineering (hard) plating. The reason I have gone with type 2 (satin finish) instead of type 1 (bright finish) is the bright finish requires a nickel undercoat, which I worry will increase the cost of the part. Is this true?

 

I'd love to hear any other input you may have. Thanks!

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Guest Ceri
Can anyone confirm this would be an appropriate plating note to include on my drawing?

 

CHROME PLATE. REFERENCE QQ-C-320 TYPE 2 CLASS 2

 

My understanding is this instructs for a satin finish engineering (hard) plating. The reason I have gone with type 2 (satin finish) instead of type 1 (bright finish) is the bright finish requires a nickel undercoat, which I worry will increase the cost of the part. Is this true?

 

I'd love to hear any other input you may have. Thanks!

 

That would be an appropriate plating note in my experience.

 

In terms of cost I believe that on the products that I have had plated their is an increased price for the bright finish over the Satin. However this is not a great increase so unless the product is very sensitive to price point I would include the finish the suits the design best and take a hit on margins in return for a better market response to having the right finish.

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Guest Buff

I would venture to add further.

 

Chrome is porous and thus the steel will rust underneeth the chrome making it 'bubble

 

The nickel plate bonds very well to the steel and the chromium in turn bonds well to the nickel and is not porous. Hense why (duplex) nickel is often specified as an 'undercoat' to the chromium.

 

In times gone by, the steel would first have a copper layer to help give reflectivity, but this is not now necessary with the duplex nickels used today.

 

Not using the nickel will mean the chromium is more likely to flake from rusting underneath the surface.

 

Another word of warning when using chromium as a wear surface. you should look into the tribilogical design of the component parts.

What forces are involved? (N)

How fast is the travel? (V)

How often will the action take palce? (Hz)

 

You may find the substrate (steel) becomes compressed under the chromium causing it to flake (think of a chocolate coated ice cream. Hard surface, soft substrate. under load the cocholate cracks.

 

'Hard' chrome plating uses a reverse electolosys to remove high spots which leave a 'satin' type finish. this is often used for hydraulic parts which need good abrasion resistance and very low surface roughness.

 

decorative 'satin' chrom is often achived by tumble abrasion.

 

Either way it's a secondaty process and will generally cost a little more than 'bright' chrome

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