Large-Diameter Riveted or Similarly Closed Pipes & Tubes, Iron or Steel (Over 16 In.)

The critical factor is the closure method. If the pipe's seam is formed by riveting, bolting, or a similar mechanical fastening process rather than by any form of welding, it belongs under 730590. Welded pipes — regardless of seam orientation — fall under 730531 or 730539. Mill certifications and fabrication records are the primary supporting documents for this distinction.

Section 232 tariffs apply to iron and steel articles broadly, but the specific treatment for Canadian-origin steel products has been subject to separate bilateral arrangements. Importers should verify the current status of any Section 232 exemptions or alternative measures applicable to Canadian steel at the time of entry, as these arrangements have changed over time.