suppplying square hollow pipe: Hengji Steel suppplying square hollow pipe :1.OD: 15*15mm-400*400mm, WT: 0.6mm-12mm ... 3.Standard: GB, ASTM, BS, JIS square pipe1.Item: Square hollow section, square pipe, square tube2.Standard: GB, ASTM, BS, JIS, 3.Material ... signed We are specialized in the supply of ERW pipe, seamless steel pipe, hollow section, galvanized steel coins, steel plate, stc. We supply steel ...