With aluminum, the most commonly used forms are plates and sheets. Fabrication shops in Minneapolis have found both ornamental and industrial uses for the metal in these formats. Rolling mills produce the various forms of aluminum from an ingot. These may weigh as much as 20 tons, but the type used to produce 1/4 aluminum plate may be lighter.
The Process
The process for producing both plate and sheets is identical to a point. They both begin in a rolling mill using an ingot roughly 6 feet wide, 20 feet long and in excess of 2 feet thick. The breakdown mill takes in a heated ingot, where it rolls it back and forth until the piece of aluminum has been reduced down to a few inches thick. The treatments that follow can use heat or cold rolling to increase the now slab of aluminum’s strength. Many of the best alloys are first heated then cooled rapidly.
Not unlike fine cheese, aluminum plate is aged either naturally or artificially. The intent of this approach is to finesse the combination of strength and corrosion resistance. At this point, the aluminum plate or sheet is at full thickness. It has not yet been cut into different gauges including 1/4 aluminum plate.
1/4 Aluminum Plate
Thickness is what determines whether the aluminum is going to be a sheet or a plate. If the flattened ingot has a thickness of between 0.008 inches to under 0.25 inches (1/4 inch), it is a sheet. If it is over one-quarter of an inch (0.250 inches), it is now considered to be aluminum plate.
Anything less thick than a sheet of aluminum is foil. According to this method, 1/4 aluminum plate or sheet is the least thick aluminum plate possible. In another system – the American metal gauge system, the number given for 1/4 aluminum plate would reflect its thickness in a non-linear measure of identification. Instead of being marked as one-quarter, the number, under both the Brown and Sharpe’s Gauge Standard (B & S) or American Gauge (AWG) would be 22.
