7304.59.20.80 - Having an outside diameter exceeding 406.4 mm

This classification, HTS Code 7304.59.20.80, pertains to seamless tubes, pipes, and hollow profiles of iron or steel, specifically those of other alloy steel and of a circular cross-section. The defining characteristic of this category is that the outside diameter of these articles exceeds 406.4 mm. These are generally large-diameter, hollow metal products fabricated without the use of welding or other joining methods, and are made from alloy steels that are not specified in other more specific subheadings.

The critical distinction for this category lies in its dimensional criteria compared to its siblings. While other categories under 7304.59.20 cover articles with outside diameters ranging from less than 38.1 mm up to and including 406.4 mm, this specific subheading is reserved for those whose outside diameter is *greater* than 406.4 mm. This significant size difference often dictates the intended application and manufacturing processes for these large-diameter tubes and pipes.

As a leaf node, 7304.59.20.80 does not have further subcategories. Therefore, any seamless, circular, other alloy steel tube or pipe with an outside diameter exceeding 406.4 mm that is suitable for use in boilers, superheaters, heat exchangers, condensers, refining furnaces, or feedwater heaters would fall into this classification. The emphasis is on the material composition (other alloy steel), construction (seamless), cross-section (circular), and the specific, large outside diameter measurement.