A slab is a semifinished product intended for further rolling and is classified in 7218. Once it has been rolled to its final flat-rolled dimensions and is ready for use or sale as plate or sheet, it moves to heading 7219 (600 mm or more wide) or 7220 (under 600 mm wide). The key indicator is whether the product has been further worked beyond the semifinished stage.

Yes. Section 232 measures apply to steel mill products broadly, including primary and semifinished forms in heading 7218. Country-specific exclusions or quota arrangements may modify the effective treatment for particular origins, so importers should verify the current status for each supplying country at the time of entry.