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.
Ideal for processing large pieces of aluminum, open die presses do not constrain the aluminum billet during the forging process and utilize flat dies free of precut profiles and designs. Aluminum blocks weighing up to 200,000 pounds and 80 feet in length can be open-die forged to create large aluminum components with optimal structural integrity. While welding and joining techniques are useful in creating large components, they cannot match the strength or durability of a forged part. Open-die forgings are limited only by the size of the starting stock.
Closed-die forging, also known as impression-die forging, can produce an almost limitless variety of shapes that range in weight from mere ounces to more than 25 tons. As the name implies, two or more dies containing impressions are brought together as forging stock undergoes plastic deformation. Because the dies restrict metal flow, this process can yield more complex shapes and closer tolerances than open-die forging. Impression-die forging accounts for the majority of aluminum forging production.
When industrial applications call for a high strength, circular cross section component, there is no match for rolled-ring forging. The process typically begins with an open-die forging to create a ring preform, shaped like a doughnut. Next, several rollers apply pressure on the preform until the desired wall thickness and height are achieved. Configurations can be flat, like a washer or feature heights of more than 80 inches. Rings can be rolled into numerous sizes, ranging from roller-bearing sleeves to large pressure vessels.
Professional racecar drivers know that forged aluminum wheels are a great choice for the punishing conditions of competitive racing. Built for speed and performance, forged wheels are extremely lightweight, very strong and exceptionally stiff. Forged aluminum wheels are found off the racetrack too. High performance sports models from Porsche, Lamborghini and Audi can all be outfitted with these sleek and high performance wheels.