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Chrome hard plating flaking on loaded threaded fasteners

February 10, 2010

I work in an engineering department in a shipyard that overhauls ships. An issue was brought to my attention that some of our stainless steel 304 chromium hard plated bolts used inside the vessel are flaking. The subject bolts vary from 1/2" to 1" in diameter and are preloaded to ~80% of material yield strength. Reports show that when the bolts are uninstalled, some flakes of chromium plating fall off the threads and can be seen on the ground.

Would the load on the bolt cause the chromium plating to separate from the base metal? Or could this be due to inadequate adhesion of the chromium to the stainless steel?

Thanks for your time

Evan Gaines
mechanical engineer - Norfolk, Virginia, USA

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There aren't too many details to go on, but it is very likely an adhesion problem as you suspected. Getting good plating adhesion on stainless steel is not as simple as plating on other steels.

Jon Barrows, MSF, EHSSC
Kansas City
February 12, 2010

Do you think spalling could be the cause of this? Just something I saw when researching... didn't know if it applies in this case.

Evan Gaines
- Norfolk, Virginia, USA
February 16, 2010

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