... 4,quick delivery constrution use hot dip galvanized square and rectangular steel pipe/SHS/RHS 1. Outer diameter:20*20-400 ... Technique: ERW, hot-rolled6. Certification: CE, ISO7. Material: Q195, Q235, Q345(16Mn), ST37, 20#, Q390, X42-X65, H40, J55, S290 ... EN10219-1:2006, EN10219-2:2006 JISG3466-889. Application: square steel pipe are widely used in machine-building, construction, metallurgy, automobile- ...