Explanatory notes
… a finish of higher precision. They may also be worked (e.g., drilled, punched, twisted or crimped), provided that … tubes and pipes to which fins or gills have been attached, e.g., by welding, are excluded ‑ generally heading 74.19 . … their entry into machines for converting them into, e.g., wire drawing stock (wire‑rod) or tubes, are, however, …