Continuously cast slabs are considered semifinished products and fall under subheading 722490, not the primary forms subheading 722410. Primary forms include ingots poured into molds and other shapes that have not yet been worked by rolling or forging.

Stainless steel is defined by a minimum chromium content (typically 10.5% or more by weight) that confers corrosion resistance. Alloy steels covered by heading 7224 contain alloying elements below that threshold or in different combinations; they are classified here rather than in the stainless headings regardless of other alloy additions.