... 3,ISO cert 4,quick delivery constrution use hot dip galvanized square and rectangular steel pipe/SHS/RHS 1. Outer diameter:20 ... or customized according to your need.4. Surface treatment: bared, galvanized, oiled, painted to prevent rust.5. Technique: ERW, hot- ... , EN10219-1:2006, EN10219-2:2006 JISG3466-889. Application: square steel pipe are widely used in machine-building, construction, metallurgy ...