... Surface:Black painting or oiled steel square tube 1)Thickness:0. ... API155Product CategoryMetallurgy, Mineral & EnergyTechniqueWelded,ERW Cold Rolled,Hot RolledSurfaceBared, Galvanized, ... to the business policy as "Quality for Survival, Product for ... 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 ...