... Advanced Roller Extrusion equipment line. 3.Certification:CE, ASTM Carbon Steel Pipes 1. STANDARD:GB/T3094-2000, GB/T6728-2002, ASTM ... Q195, Q215, Q235, Q275, Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE; Or ... in this area.We engaged in research square and rectangular steel tube at the beginning of company established, now our ...