Between the production of aluminum from bauxite to well-known end products like buildings and beverage containers lies processing. The processing of aluminum—using castings, extrusions and mill products—allows the industry to support end users to become more innovative with their designs and utilize greater technologies. Lightweight, durable and infinitely recyclable, value-added aluminum products can lower energy costs and carbon emissions in dozens of applications.
Casting is a simple, inexpensive and versatile way of forming aluminum into a wide array of products. Such items as power transmissions and car engines and the cap atop the Washington Monument were all produced through the aluminum casting process. Most castings, especially large aluminum products, are usually made in sand molds.
Extrusion is a widely used aluminum forming process that delivers almost unlimited possibilities in product design. The extrusion process is similar to the childhood pastime of creating long strands of play-dough by forcing the product through a plastic-shaped die. Fortunately, aluminum’s weight, strength and high thermal conductivity vastly outweigh that of play-dough, leading to its presence in a wide range of consumer and industrial goods. The aluminum extrusion process has the added benefit of enabling fast product development cycles due to its low-cost and flexible tooling. Manufacturers can accelerate prototype and testing phases by rapidly creating and evaluating different designs.
Forging is a manufacturing process where metal is pressed, pounded or squeezed under great pressure to produce high-strength parts. Forged aluminum is ideal for applications where performance and safety are critical but a lighter-weight metal is needed for speed or energy efficiency. The forged aluminum wheels on Daytona racecars are a perfect example. There are primarily three types of forging processes: open-die forging, ideal for larger aluminum components; closed-die forging, well-suited for more intricate designs and tighter tolerances; and ring-rolled forging used to create high-strength ring-shaped applications.
Aluminum powder, found in products ranging from suntan lotion to lightweight concrete to solar panels, is produced by melting aluminum ingot in a gas furnace and spraying the molten metal under high pressure into a fine granular powder. Two types of powder can be produced from this process, depending on the atomizing gas used to "blow" the molten aluminum from a nozzle tip.
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.
When aluminum is passed between rolls under pressure, it becomes thinner and longer in the direction in which it is moving. This simple process is the basis for producing aluminum plate, sheet and foil. Sheet, the most widely used form of industrial aluminum, is used in applications including aerospace (the skins of planes), transportation (auto body sheet), packaging (can bodies and ends) and construction (building facades).