square hollow section 30*30-800*800mm 3-25mm Products NameSquare hollow sectionSizeDiameter30*30-600*600Thickness3-25Length6-12mMaterialsQ235,Q345,20#,ST37,ST44,ST52,ASTM A53, ASTM A106,STKR 490 and so on StandardsJIS G3466, DIN EN10210, DIN EN10219, ASTM A500, GB/T3094-2000,GB/T6728-2002Useconstruction structure, machinery,hall structure,airport struture, shipbuilding, automotive parts, sun ...