Mild Steel Square Tube

Mild steel square tube (also known as mild steel square hollow section or box section) is hot rolled steel that has been formed into a square tube. It is commonly referred to as HSS (meaning Hollow Structural Section).

Typically, box sections have an inside seam due to it being welded. Mild steel square tube/box section is measured by taking the outside dimensions (which are the same size) and then the wall thickness.