... CE,ISO JIS Rectangular Tube 1. STANDARD:GB/T3094-2000, GB/T6728-2002, ASTM A500, JIS G ... Q275, Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, ... tower crane.6. SPECIFICATION: SQUARE TUBE(MM) THICKNESS (MM)SQUARE TUBE (MM)THICKNESS(MM)20*301.5 ... engaged in research square and rectangular steel tube at the beginning of company established, now ...