Square hollow section are commonly manufactured according to international standards such as ASTM A500, EN 10219, and AS 1163, which define the dimensional tolerances, mechanical properties, and testing requirements of Carbon Steel Pipe. Square hollow sections ranging from 38x25mm to 600x600mm Standard: AS1163 C250,C250L0,C350,C350L0,C450,C450L0 Grade C250 and Grade C350 Circular Hollow Sections (CHS) Grade C350 and Grade C450 Rectangular Hollow Sections (RHS) Grade C350 and Grade C450 Square Hollow Sections (SHS) AS1163 square welded steel pipe Grade and Chemical Composition (%) Steel Grades Chemical composition( cast or product analysis % Circular hollow sections Rectangular hollow sections ≦15 >15≦30 30 ≦15 >15≦30…