scope:

GENERAL

Electrodeposited chromium is applied to metal parts for one or more of the following engineering purposes:

wear resistance;

corrosion resistance coupled with wear resistance;

reclamation of worn or over-machined parts.

DEF-160 'Chromium plating for engineering purposes' details the requirements for processing and inspection of chromium plated parts for the above purposes.

For technical and economic reasons, early and close liaison between designers, manufacturers, platers and inspectors is essential. As it is virtually impossible to test the adhesion of chromium coatings in a nondestructive manner, integrity of workmanship is especially important and there is clear need for careful control at each stage of processing. including inspection for cleanliness of the surface immediately before plating.

Chromium coatings are hard but are brittle and readily crack, producing stress concentrations which may reduce the strength of the plated part particularly as regards resistance to fatigue. Additionally, steel may be embrittled by absorption of hydrogen released during the cleaning and plating processes. These and other design factors which have to be taken into account in order to obtain satisfactory plating without undue adverse effect on the mechanical properties of the part, are dealt with in this guide.