Engineering chrome can be used for corrosion protection, but is generally used when the deposit is needed to repair a part. It also can be used for wear resistance. Examples of such parts are pistons, cylinders, aircraft engine parts, cutting tools, dies, oil tool parts and valves. The coating can be applied as a thin (generally less than 0.0002 in) or a heavy coating (over 0.0005 in). Thicker deposits generally require machining after plating to achieve blueprint dimensions or surface finish requirements.
Deposits may range from coverage to .030 inch. Hardness will range from Rockwell "C" 60-70. Chromium has poor throwing power. Recessed areas such as holes or in corners of shoulders will have less thickness (or no thickness) than the majority of the part. Because of the poor throwing power of the bath, conforming anodes play a big part when plating chrome. The more complicated the plating surfaces, the more effort in developing the tooling and fixturing will be needed.
Benefits of Hard Chrome
- Corrosion potection
- Part repair
- Wear resistance