Aluminium sheets, plates and coil.Aluminium Trading supplies aluminium sheets, plates and coil to hundreds of industries throughout Southern Africa each month. The metals strength, superb corrosion resistance and light-weight structure make it a very popular material to work with to meet the modern and intricate demands of today’s world. In fact, Aluminium has become the second most used metal on the planet after iron/steel. But a very common question we still receive is “What are the differences between aluminium sheets, plates, and coil?”
When looking at the three types of aluminium products, the only difference is the thickness. The thickest product being aluminium plate followed by sheet and finally, coil being the thinnest. However, the exact thicknesses separating each category depends on a few factors. Metals, in general, have been differently classified for thickness depending on the metal, the gauge, and even the application.
Historical Metal Standards – Inconsistent?
Before the development of modern, accurate measurement devices and technology, ‘gauges’ were the standards used to classify the thickness of metals, wires in particular. Over time, each metal industry formed its own independent standards. This resulted in gauge numbers that vary for aluminium, copper, brass and the many different variants of steel. An example of this can be seen in the Dictionary of Units of Measurement. This publication defines 10-gauge aluminium as being 0.259 centimetres thick, while 10-gauge standard steel is 0.341 centimetres and a 10-gauge galvanized steel is 0.351 centimetres.
Due to the confusion caused by the gauging system, the American Society for Testing and Measurement (ASTM) stated in specification ASTM A480-10a; ‘The use of gage numbers is discouraged as being an archaic term of limited usefulness not having general agreement on meaning’.
Modern Measurements for Metal Thickness
Today it has become common practice to simply specify an exact thickness for any given product. Although gauges are still listed in the United States, South African and European industries have used the term less and less frequently in recent years.
In terms of aluminium and its alloys in South Africa, there is still a bit of uncertainty over the exact thickness of the metal in classifying it as either sheet, plate or coil, with most distributors and fabricators deciding these classifications by themselves. At Aluminium Trading we provide aluminium plate with a thickness greater than 4.5mm, aluminium sheet with a thickness of 0.5mm – 3mm, aluminium coil with a thickness of 0.5mm to 0.6mm and foil with a thickness of approximately 0.29mm.
To demonstrate the difference in thickness amongst different distributors we contacted Mr Kent Bell, a Market Manager at Hulamin South Africa, and asked for their classifications on aluminium thicknesses. Hulamin specialises in rolled aluminium products for precision and high technology applications, and are one of the largest producers of rolled aluminium products in Africa.