... *550mmThickness3-25 mmMaterialQ235B ,Q345B,20# ,ST37,ST44,ST52,ASTM A53, ASTM A 106 and so onStandardsGB/T3094-2000 or JISG 3466 ... of both domestic and abroad markets.And they are wildiy using in PV modules as solar frames/suppor,construction structure,machinery, ... steel tube , weld steel tube ,oval tube, steel tube with the compound sections,spiral steel pipe,insulation steel pipe,anticorrosion ...