... , Q215, Q235, Q275, Q345, 20#, 45#, Stainless steel, Seamless steel, Alloy steel.3. SURFACE:Bared, Galvanized, Oiled, Color Paint, 3PE; ... 3).Construction engineering: steel structure construction, sports venue, three-dimensional garage, exhibition hall.(4).Decoration: wrought iron doors and ... this area.We engaged in research square and rectangular steel tube at the beginning of company established, now ...