Tumbling Test for Plated Parts? 2

[MechEng1977]

I am trying to compared the durability of various grades of both Phosphate and Zinc plating. We (Engineers) were thinking that besides the ASTM B117 Salt Spray Test that we should do a test were the parts are tumbled and then evaluated for corrosion resistance because the bolt nut assym in question are often handled roughly.

Does such a tumbling test exist?

Thanks in advance.

 

[tomwalz]

We do it here in a rotary, tumbling deburrer or in a rotary sandblaster depending on service requirements.

In our experience it is a go / nogo deal. If the plating stays on in testing then it will stay on in use.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[MechEng1977]

So I guess there is no specific test?

What aggregate did you use in the tumbler?

 

[CoryPad]

There is not a standardized test to induce tumbling damage to coated parts. There are proprietary tests for this purpose.

On the other hand, there are standardized tests for other damage types, like scribing to the base metal, gravel chipping, etc.

 

[MechEng1977]

Can you please provide the test numbers for the "scribing base metal and gravel chipping"?

 

[CoryPad]

For scribing to base metal:

ASTM D 1654 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments

For gravel chipping:

SAE J400 Test for Chip Resistance of Surface Coatings

 

[MechEng1977]

Thanks and I also found ASTM D3170-03

 

[MechEng1977]

The ASTM D3170-03 was far too complex. Instead, I opted for a simple tumble test with a gravel mixer. One minute with just the parts in question. I then put some 3/4" crush stone into the mixer and ran the test for another minute.

The Zinc coating seems to be tougher than the Phosphate coating. We are now performing the ASTM B117 Salt Spray test.