... Square Steel Pipe : 1. More Thickness: 3.0-22.0mm 2. Advanced Roller Extrusion equipment line. 3.Certification:CE,ISO SpecificationsSquare Steel Pipe ... Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE; ... Or Other Anti-corrosive Treatment.4. TECHINQUE:Hot rolled, Cold rolled, ERW, High-frequency welded ...