Structural shapes

Structural steel is a category of steel used as a construction material for making structural steel shapes. A structural steel shape is a profile, formed with a specific cross section and following certain standards for chemical composition and mechanical properties. Structural steel shapes, sizes, composition, strengths, storage practices, etc., are regulated by standards in most industrialized countries.

Structural steel members, such as I-beams, have high second moments of area, which allow them to be very stiff in respect to their cross-sectional area.

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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