The HTS heading does not formally separate plate from sheet by name — both fall here as long as thickness exceeds 0.2 mm. In commercial practice, plate is generally understood as material above about 6 mm thick, but for classification the key distinctions are alloy status and whether the shape is rectangular. Duty rates and trade remedy coverage may differ by subheading, so the specific subheading rather than the commercial label governs.

Yes, the US has antidumping and countervailing duty orders on common-alloy aluminum sheet from several countries. The orders define covered alloys and gauges precisely, and exclusions exist for certain aerospace-grade and other specialty alloys. Importers should review the current order scope and, if uncertain, request a scope ruling from the Department of Commerce before importation.