"Sherardising" is a solid - state zinc diffusion process. After pickling, articles to be coated are packed in a steel drum with an appropriate quantity of zinc dust mixed with alumina or sand, The drum is heated to below the melting point of zinc (360-430oC) for several hours , during which it is rotated, to tumble the charge. The resulting zinc rich surface layer is about 0.0005 inches thick (can be greater), is dark grey and can be oiled or stained.

The process offers effective rust - proofing of steel.

Nuts, bolts, screws etc can be treated; the process is suitable for tubing and hollow sections; also chains.

For further information refer to