History of HSS
In the 19th century, the first production methods for seamless and welded circular hollow sections were developed. In 1886, the Mannesmann brothers developed the skew roll piercing process (Schrägwalzverfahren) which made it possible to roll short thick walled tubulars.
The excellent properties of the tubular shape have been recognized for a long time; i.e. from ancient time, nice examples are known. An outstanding example of bridge design is the Firth of Forth Bridge in Scotland (1890).
In the UK, or other countries which follow British construction or engineering terminology, the term HSS is not used. 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.
Hollow Structural Sections
Hollow Structural Sections (HSS) is high-strength welded steel tubing used as structural elements in buildings and other structures and a variety of manufactured products. It is produced in round, square and rectangular shapes and a broad range of sizes. Benefits include aesthetic appeal, high strength-to-weight ratios, uniform strength, cost-effectiveness and recyclability.
HSS is sometimes mistakenly referenced as hollow structural steel. Rectangular and square HSS are also commonly called tube steel or structural tubing. Circular HSS are sometimes mistakenly called steel pipe though true steel pipe is actually dimensioned and classified differently from HSS. (HSS dimensions are based on exterior dimensions of the profile, while pipes are essentially dimensioned based on interior diameters.) The corners of HSS are heavily rounded, having a radius which is approximately twice the wall thickness. The wall thickness is uniform around the section.