To begin with hard facts, according to the 2015 ‘Stainless Steel in Figures’ report published by the International Stainless Steel Forum, cold-rolled flats accounted for 47.7% of all foreign trade in 2014, while hot-rolled plate, coil and sheet materials were 6%. Flats thus make up by far the largest share of stainless steel production so it is no surprise that they are used in a wide range of industries, environments and applications. These include high-end construction, process industries, marine environments, storage tanks, oil and gas pipes, to name but a few.
Stainless steel sheets are often used in buildings and architectural applications. Depicted here is the entrance to the metro in Granada, Spain, covered in type 304 stainless steel. Photo © Acerinox
As the term collectively describing them suggests, sheet, coil, plate, strip and other product types belonging to the same shape family are characterised by a flat surface. While this shared characteristic is fairly obvious, their differences may be less so. In a recent article published in Stainless Steel World News, James Chater explained them clearly and succinctly, outlining at the same time how flats come into existence in the first place. He wrote:
“Sheet, coil and plate start life as slab, a type of semi-finished steel usually measuring between 5.5 and 7.8 inches thick (though for quarto plate, thicknesses of up to about one foot are known), 30–85 inches wide and an average of 20 feet long. After casting, slabs are hot rolled, cold rolled and coiled into sheet and plate products. During rolling the steel flattens and lengthens, whereas the width stays the same.
The difference between sheet and plate is that the former is no more than about a quarter of an inch thick. Plate is normally produced by hot rolling. It has a minimum width of eight inches, with a thickness ranging from one quarter of an inch to about half a foot in the case of very thick quarto plate. Thinner than either sheet or plate is strip, a rolled product that is under 3/16 inches thick and under 24 inches in width. The most common differences among steel bars, strip, plate and sheet lie in their physical dimensions of width and thickness.”
To learn more about this topic, see the December issue of Stainless Steel World News, pp. 5–6, or read the PDF version of the article.