... 2. Advanced Roller Extrusion equipment line. 3.CE,ISO Hollow Square Steel Tube 1. STANDARD:GB/T3094-2000, GB/T6728-2002, ASTM ... -20052. MATERIAL:Q195, Q215, Q235, Q275, Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE ... , tower crane.6. SPECIFICATION: SQUARE TUBE(MM) THICKNESS (MM)SQUARE TUBE (MM)THICKNESS(MM)20*301.5-3.2590*1902.5-14 ...