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Steel tubes Chromium detachment under compressive loading  

January 14, 2009

Hi all,
I would galdy appreciate if anyone could help with the stress(proof/ultimate) that would cause a chromium to detach from steel tubes under tensile/compressive loading.

Any reference text and/or source would be highly appreciated.

Regards.

Phil.N

Phil Neil
product designer - Bristol, United Kingdom

Hi, Phil. You can probably find the strength of hard chrome plating and the strength of the bond in Safranek, but I think you'll find that the chrome will crack under tensile load rather than detach. The landing gear of jumbo jets is chrome plated high strength steel, shot peened before plating to try to minimize the tensile stresses. When done properly, I believe that the chrome is not going to come off of a tube where the stress is at right angles to the bond no matter the load.

Regards,

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Even if properly done, the bond strength and different mechanical properties between steel and plated chrome will determine an upper stress limit above which, either the bond or the plate colapse. Thick layers of chrome are stronger, so the bond may be the weak point and there may be a separation. Thin ones tend to crack first. For this reason chrome is not considered suitable for very heavy coatings over parts subject to deformation.

Guillermo Marrufo
Monterrey, NL, Mexico