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.
The shapes available are described in many published standards worldwide, and a number of specialist and proprietary cross sections are also available.
A steel I-beam, in this case used to support timber joists in a house.
I-beam (I-shaped cross-section - in Britain these include Universal Beams (UB) and Universal Columns (UC); in Europe it includes the IPE, HE, HL, HD and other sections; in the US it includes Wide Flange (WF or W-Shape) and H sections)
Z-Shape (half a flange in opposite directions)
Tee (T-shaped cross-section) or Rail profile (asymmetrical I-beam).Also could be Railway rail, Vignoles rail, Flanged T rail, Grooved rail and Bar, a piece of metal, rectangular cross sectioned (flat) and long, but not so wide so as to be called a sheet.
Open web steel joist
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).