Aluminum rod and bar is produced by several different processes namely extrusion, rolling and coiling, or drawn directly from molten aluminum. These processes elongate the aluminum into circular or bar-shaped pieces that can be machined into all kinds of applications. Many machine and equipment parts, such as rivets, nails, screws and bolts, are made from rod and bar. Aluminum wire is used pervasively in electrical transmission applications due to its superior conductivity and non-corrosive nature. Every-day products produced from wire, rod and bar include chain-link fence material, aluminum antennas, zippers and those handy re-twistable twist-ties used to keep food fresh.
Aluminum rod, bar and wire products can be produced in several ways. One method is similar to rolling sheet. A long, square ingot is heated, progressively reduced in cross-section by passing it through a series of rolls, and then coiled. The coils are heated and, if slated to become wire, pulled through smaller and smaller dies. Extruded aluminum can also be drawn directly into bar, rod and tube formations and then progressively thinned through dies.
Made from aluminum rod, wire is, by definition, less than 3/8 inch in diameter. Electrical conductor is made by stranding several wires into a single piece. Electrical conductor rod can also be drawn and stranded directly from molten aluminum.
Electrical transmission lines are by far the largest application for aluminum rod and bar products. This is a market in which aluminum has virtually no competition from other metals. Aluminum is simply the most economical way to deliver electrical power. Aluminum wire and cable are also used almost anywhere there is an electrical impulse to conduct—in commercial buildings, machinery and equipment, transportation and consumer durables. Wire and cable are used for little jobs we seldom think about, such as the non-rusting staples in tea bags and re-twisting twist-ties.
Today’s aluminum building wire is safe, reliable and cost effective. Important changes in the production of aluminum building wiring began in 1972 when, for the first time, it was manufactured with its own metal, not a poor fitting hand-me-down from electrical utility applications. In the mid 1980s, metallurgists developed an aluminum alloy that bridged the gap in key metal characteristics between copper and aluminum. This improved alloy has significantly different properties from the aluminum conductors used in 1950s and 1960s and is fully recognized and approved by today’s industry standards.