Depending on the particular process involved in manufacturing the base metal component, there is a selection of materials to be considered.

In considering steel, DMC-140 is a readily headable material, whereas DMC-287, a leaded steel, is not. If the component is to be made via a machining process, the DMC-287 would produce the best, least expensive part.

In copper, DMC-133 (OFHC) is the best heading grade and DMC-137 is the better machining material.

Brass is not as desirable a composite backing material as the coppers; however, it is required in many applications. If the part is to be headed, the selection would be DMC-120 as contrasted to the better machining DMC-122. In most instances, the leaded or sulphurized materials cannot be successfully headed without cracking.

In the manufacture of composite weld buttons, the selection is most usually DMC-140 nickel plated. Other materials employed are DMC-151 (nickel Silver), DMC-180 (monel) or DMC-210 (Grade A nickel). These materials offer more resistance to corrosion, but at a higher cost.

Composite contact rivets employing tungsten faces and the platinum family materials normally are made on nickel-plated steel. Since these materials are used in relatively low current applications, the low conductivity of steel does not present a heat rise problem. In the use of silver and silver alloy face materials, the normal selection is copper or brass materials for the backing.

Where precious metal plating over a base metal is sufficient in the contact application, DMC-130 (ETP copper) is a typical choice.

Properties of Deringer Base Metals