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| = Introduction = With so many international standards, there are many shapes for profiles. This page gives an overview. == Shapes and designation == What is an I- and what is a H-profile? It is subjective, Do I-profiles have a larger height / width ratio? Or a different web thickness / flange thickness compared to H-profiles? A senseless discussion. And when is an I-profile a beam or a bearing pile or a column? An engineer is free to use a column as a beam. What is a beam? The association in our mind is a horizontal piece of steel, able to resist vertical forces. Technology changes too. I's were traditionally made by rolling, milling hot steel in a desired shape. Today we see them welded too, composed from sheet metal. They used to be rolled by using low performance steel with a nice price tag. Nowadays high performance steel is an option too, in order to reduce weight, tensile strength is increased. And if you want stainless steel, you can get it. Even hollow I's are introduced to the market. So we put everything together and designate it all as a family of I-shapes or I-profiles. That includes for example W-beams (Wide flange), Rolled Steel Joists, Double T's and even wooden shapes. Horizontal parts of the "I" are called flanges and the vertical part between the flanges is called the web. Concerning shapes, there are major differences in principles: There are tapered and parallel flanges. Minor differences can be radii or production details like welded I-beams. A similar approach can be applied to Channels. These are rolled. But a UNP is a channel too, where "U" stands for the shape. Cold U-profiles are common. Cold C-profiles typically have, compared to U-profiles, two extra flanges. So we end up with a family of U-shapes with three planes (two flanges and one web) and a family of C-shapes with, compared to U-shapes, two extra flanges, totalling five planes. Though tempting, channels are better not called C- but U-shapes. == Standards and designation == Every standard covers many dimensions and shapes. A standard also covers a market area. US ASTM-beams are not a logical choice in Europe, just as Russian GOST-beams are not practical in Great-Britain. A standard acts as a main group identifier for choosing a product for a specific geographic area. But, with the world becoming smaller, the offer in terms of variety is increasing. Under each standard, designation varies. Russia based GOST uses straight forward numbers, Britain based BS uses parameters with lots of digits (historically from inches to metric). Designating a GOST-profile is very easy while designating BS-profiles requires serious typing skills. == Designations == |
