Pre-galvanized square/rectangular tube: Pre-galvanized square/rectangular tube is made of hot dipped galvanized steel strip directly.
Hot dipped galvanizedsquare/rectangular : Hot dipped galvanized square/rectangular tube owns thicker zinc coating than pre-galvanized square/rectangular tube. Black tubes will be dipped into zinc pool for galvanizing.
Electro galvanized square/rectangular : The technology of electro galvanized square/rectangular tube is similar to hot dipped galvanized tube, but the thickness of zinc coating is less than hot dipped galvanized tube.
Painted square/rectangular:Painted square/rectangular to remove the rust and clean the oil first and then paint the required color paint.
Standard:GB/T6728:2002 , ASTM A500 , JIS G3466 , EN10210 ,EN10219
Steel Grade: GB/T6728:2002 : Q195 , Q235 , Q345
ASTM A500:GR. A , GR. B, GR. C , GR. D
JIS G3466 : SS440,SS540
EN10210, EN10219: S235JR ,S275JR,S355JR, S355J2H