... 20#, ST37, ST44, ST52, ASTM A53, ASTM A106 Rectangular hollow section:1.Item: square pipe2.Standard: GB, ASTM, BS, JIS ... 15mm-400*400mm, WT: 0.6mm-12mm1. Commodity specificationsSquare hollow section2. Process methodCold drown, high frequency welded3. MaterialQ195--- ... of ERW pipe, seamless steel pipe, hollow section, galvanized steel coins, steel plate, stc. We supply steel as the manufacturer's price ...