... corrosive Treatment.4. TECHINQUE:Hot rolled, Cold rolled, ERW, High-frequency welded.5. APPLICATION:(1).Machinery manufacture: glass machinery, agricultural ... : automobile manufacture, ship manufacture, container, tricycle, tower crane.6. SPECIFICATION: SQUARE TUBE(MM) THICKNESS (MM)SQUARE TUBE (MM)THICKNESS(MM)15* ... need.Perfect after-sale service to solve your worries. High Quality Square steel pipe