Steel structure

Structural steel is a category of steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries.

Most structural steel shapes, such as I-beams, have high second moments of area, which means they are very stiff in respect to their cross-sectional area and thus can support a high load without excessive sagging.

The shapes available are described in many published standards worldwide, and a number of specialist and proprietary cross sections are also available.

While many sections are made by hot or cold rolling, others are made by welding together flat or bent plates (for example, the largest circular hollow sections are made from flat plate bent into a circle and seam-welded).

The terms angle iron, channel iron, and sheet iron have been in common use since before wrought iron was replaced by steel for commercial purposes. They have lived on after the era of commercial wrought iron and are still sometimes heard today, informally, in reference to steel angle stock, channel stock, and sheet, despite that they are misnomers (compare "tin foil" still sometimes used informally for aluminum foil). In formal writing for metalworking contexts, accurate terms like angle stock, channel stock, and sheet are used.

Most steels used throughout Europe are specified to comply with the European standard EN 10025. However, many national standards also remain in force.

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