1. Material: mild steel Q235 with Yeild strength 235Mpa, mild steel Q345 with yeild strength 345Mpa 2. Welding penetration MIN 60%, American Lincoln welding flux, wire solder and soldering machine (automatic submerged arc welding) 3. Octagonal twisting degree Max 4 degrees 4. Steel thickness Max 6MM 5. Max length 16M one piece 6. Finish: hot dip galnvanized or powder coated