... Extrusion equipment line. 3.Certification:CE,ISO SpecificationsSquare Steel Pipe 1. More Thickness: 1.0-22.0mm ... , Q275, Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE; Or Other ... railway, aviation, expressway, overpass, road fence, traffic signs.(3).Construction engineering: steel structure construction, sports venue, three-dimensional ...