... -600*600mm. 5.Surface:Black painting or oiled steel square tube 1)Thickness:0.5-30mm2)Size(dia.): 15 ... ,Automobile chassisWater Pipelines, Waste waterlines , Water supply mainsDeep tube wells casing pipes, Gas/Natural gas pipe lines, Oil pipe ... welded steel pipe manufacturing group. We have cooperated with Bao steel, Wu yang steel, TPCO, Baotou steel, Shou gang Jin tang Steel, An gang Steel, Daye Steel ...