Wire Facts

Engineering and Technical Information for the Design and Use of Copper Alloy Wire

At Fisk, we’re continuously exploring specialty alloys to meet today’s rigorous balance of design requirements — premium-quality wires that are lighter, stronger, more flexible, more conductive, more tolerant of extreme operating environments yet environmentally friendly.

Our drive to innovate notwithstanding, basic engineering and technical standards hold true. This information is available through the links, below, for your convenience. It may prove valuable as you consider your next design.

Wire: An Engineered Material

Physical properties are alloy dependent. Mechanical properties are also alloy dependent but are controlled primarily by the wire manufacturing process.

Cast and Camber

Wire, as commercially produced, is not straight. The desired curvature should always be considered, and in some instances actually specified.


One of the main attributes of copper alloys is their high electrical and thermal conductivity, making them quite attractive in electrical and electronic applications.

Dimensional Relationships

Formulas for wire dimensions assume corners to be a perfect arc of a circle. In practice, the shape of the corner is between an arc and a chamfer.

Ductility and Bend Formability

Formed parts may require bending, coining, folding, etc., and may require multiple measurement parameters to represent multiple ductility requirements.

Edges and Corners

Square, rectangular or flat copper alloy wire can be produced with a variety of standard edge conditions. Equally, they can be produced with special edge conditions.

Grain Size

Solid metallic materials are crystalline in structure. The element atoms are arranged in a regular three-dimensional array. Copper alloys, as are most metals, are polycrystalline.

Mechanical Reflow®

A processing method that affects the electroplating of wire for electronic interconnects and components, followed by subsequent operations that produce the final product.

Plating Thickness

Copper alloy wire is often electroplated with precious metal coatings. These can be singular, as in silver plated copper, or of multiple layers, as in nickel-gold plated copper.

Glossary of Terms for Copper Wire

A list of terms and their associated definitions relating to copper alloy wire and the processes involved in their manufacture.


Solderability is defined as the ability of a metal to be wetted by molten solder. Measurement of solderability can be done several ways, each with a different purpose or advantage.

Surface Finish

The surface finish of wire can be of crucial importance to the manufacture and performance of fabricated wire parts, and is the result of the working surfaces, rolls and dies used in processing the wire.

Temper Designations

In wire, the nominal temper designation is usually related directly to the amount of cold reduction (cold work) stated in terms of American Wire Gauge (AWG) gauge numbers.

Tensile, Yield and Elongation

When an alloy is cold worked by rolling or drawing, tensile (the primary specification parameter) and yield strengths increase while elongation decreases.

Wire Length

Wire length is calculated using different formulas specific to the shape — round, square or rectangular, or round-edge flat wire, which includes a correction factor for the change from rectangle to round edge.

Dog Legs

The phenomenon of bent square or rectangular wire near the barrel of layer level wound spools has been termed “Dogleg.”