This specification covers bare round copper-clad steel wire for electronic application. Four classes of copper-clad steel wire are covered as Class 30HS, 30A, 40HS, and 40A. The wire shall consist of a core of homogeneous open-hearth, electric-furnace, or basic-oxygen steel with a continuous outer cladding of copper thoroughly bonded to the core throughout. The copper-lad steel wire shall conform to the tensile strength and elongation requirements. Electrical resistivity test shall be performed at a specified temperature of each class of wire and shall not exceed the values prescribed in this specification. Dimensional measurements shall be made with a micrometer caliper and shall withstand torsion test without fracturing. Copper cladding to the steel of each of the four specimens shall conform to the adhesion criterion. Surface finish shall meet the required allowable number of defects.

1.1 This specification covers bare round copper-clad steel wire for electronic application.

1.2 Four classes of copper-clad steel wire are covered as follows:

1.2.1 Class 30HS—Nominal 30 % conductivity hard-drawn,

1.2.2 Class 30A—Nominal 30 % conductivity annealed,

1.2.3 Class 40HS—Nominal 40 % conductivity hard-drawn, and

1.2.4 Class 40A—Nominal 40 % conductivity annealed.

1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are in SI units.