Bronze Plates, Sheets & Strip Over 0.15 mm Thick, Not in Coils

Phosphor bronze (copper-tin with phosphorus deoxidizer) commands a distinct commercial market — particularly for precision spring stock and electrical contacts — and historically has had different trade patterns than other bronze grades such as aluminum bronze or silicon bronze. The separate 10-digit lines (e.g., 7409391030 for phosphor bronze versus 7409391060 for other bronze, both over 5 mm thick) allow Customs to track these commercially distinct products separately.

A mill test certificate identifying the alloy by standard designation (e.g., C510 or C511 for phosphor bronze) and confirming the presence of phosphorus as a deoxidant is the key supporting document. Alloys such as C630 (aluminum bronze) or C655 (silicon bronze) are not phosphor bronze and should be declared under the NESOI bronze lines. Importers should retain alloy certifications as part of their entry records.