... Roller Extrusion equipment line. 3.CE,ISO Cold Formed Rectangular Steel Tube 1. STANDARD:GB/T3094-2000, GB/T6728-2002, ... Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE; Or Other Anti-corrosive Treatment.4 ... in this area.We engaged in research square and rectangular steel tube at the beginning of company established, now our technology ...