... :15*15-600*600mm. 5.Surface:Black painting or oiled steel square tube 1)Thickness:0.5-30mm2)Size(dia.): 15*15 ... a large company specializing in the production and selling of square, round, rectangular pipe surfaced with galvanized coating, polish, black ... . We have cooperated with Bao steel, Wu yang steel, TPCO, Baotou steel, Shou gang Jin tang Steel, An gang Steel, Daye Steel, HBIS and other major ...