... 4,quick delivery constrution use hot dip galvanized square and rectangular steel pipe/SHS/RHS 1. Outer diameter:20*20-400* ... bared, galvanized, oiled, painted to prevent rust.5. Technique: ERW, hot-rolled6. Certification: CE, ISO7. Material: Q195, Q235, Q345(16Mn), ST37 ... 2006, EN10219-2:2006 JISG3466-889. Application: square steel pipe are widely used in machine-building, construction, metallurgy, ...