Hollow structural section

Rectangular and square HSS are also commonly called tube steel or box section.

Rather, the three basic shapes are referenced as CHS, SHS, and RHS, being circular, square, and rectangular hollow sections.

Typically, these designations will also relate to metric sizes, thus the dimensions and tolerances differ slightly from HSS.

HSS, especially rectangular sections, are commonly used in welded steel frames where members experience loading in multiple directions.

During the manufacturing process flat steel plate is gradually changed in shape to become round where the edges are presented ready to weld.

For example, barriers around parking areas (bollards) made of HSS are often filled, to at least bumper height, with concrete.

A hot-rolled HSS-box section cut open with a bandsaw, demonstrating residual stress