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