Editing Hollow structural section (section)

==Use in structures==
HSS, especially rectangular sections, are commonly used in welded steel frames where members experience loading in multiple directions. Square and circular HSS have very efficient shapes for this multiple-axis loading as they have uniform geometry along two or more cross-sectional axes, and thus uniform strength characteristics. This makes them good choices for [[column]]s. They also have excellent resistance to [[torsion (mechanics)|torsion]].

HSS can also be used as [[beam (structure)|beams]], although ''wide flange'' or [[I-beam]] shapes are in many cases a more efficient structural shape for this application. However, the HSS has superior resistance to [[buckling|lateral torsional buckling]].

The flat square surfaces of rectangular HSS can ease construction, and they are sometimes preferred for architectural aesthetics in exposed structures, although elliptical HSS are becoming more popular in exposed structures for the same aesthetic reasons.

In the recent past, HSS was commonly available in [[mild steel]], such as [[A500 steel|A500 grade B]]. Today, HSS is commonly available in [[mild steel]], [[A500 steel|A500 grade C]]. Other steel grades available for HSS are A847 (weathering steel), A1065 (large sections up to 50 inch sq made with SAW process), and recently approved A1085 (higher strength, tighter tolerances than A500).