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Is salt spray test applicable for chemically blackened parts?

Is salt spray test applicable for chemically blackened steel parts?

If so, If we do salt spray test for chemically blackened parts how many hours the parts will with stand with out forming rust? Kindly clarify

Bhargavi bhargavi
- Chennai, Tamil Nadu, India
May 24, 2010

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It is not a common test. You must comply with whatever the specification that you are blackening to and your customers purchase order. James Watts - Navarre, Florida Bhargavi, What are you trying to prove with the salt spray test? Is this someone else's design or are you trying to emulate some exposure situation? Black oxide has little corrosion resistance itself, but is usually used to help key other processes, such as oil retention (a small amount anyway) or a paint/varnish key etc. The other thing to know about salt spray is that it cannot emulate realtime situations and is used only as a performance check. Brian Terry Aerospace - Yeovil, Somerset, UK

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June 2, 2010

Well bluing or blacking on steel is commonly black oxide. Black oxide has absolutely no resistance to sodium chloride and water. With that in mind I assume no one has ever bothered to salt spray test it. There really is no point as one knows what the outcome would be before conducting the test.

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada

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June 12, 2011

That was a good point of knowing the black oxide has less resistance to the SST / Chloride.
However,the blackoxide nut .screws are commonly used and there has been many incidence that the screw/nut/bolt get rusty along the way of the shipment.
Hence, one need to know what will be the best test method to test the black oxide towards corrosion.

Regards.

H . Hussain
- Malaysia