7304.39.00.06 - Having an outside diameter of 190.5 mm or more but not exceeding 285.8 mm

This HTS classification, 7304.39.00.06, pertains to seamless tubes and pipes of iron or nonalloy steel that are specifically designed and manufactured for use in high-temperature applications within industrial equipment. These include components for boilers, superheaters, heat exchangers, condensers, refining furnaces, and feedwater heaters. The defining characteristic of this subcategory is its specific size range, requiring an outside diameter of 190.5 mm or more, but not exceeding 285.8 mm.

This particular code is distinguished from its siblings by its precise diameter specifications. HTS 7304.39.00.02 covers smaller diameter tubes (less than 38.1 mm), while 7304.39.00.04 encompasses tubes with diameters ranging from 38.1 mm up to, but not including, 190.5 mm. Conversely, HTS 7304.39.00.08 covers tubes with diameters exceeding 285.8 mm. Therefore, this classification exclusively applies to seamless iron or steel tubes and pipes within the specified 190.5 mm to 285.8 mm outside diameter range, intended for the mentioned industrial heat transfer equipment.

As this classification represents a leaf node in the HTS structure, there are no further subcategories to introduce. The specific criteria for classification under 7304.39.00.06 are therefore its seamless construction, its material composition of iron or nonalloy steel, its circular cross-section, its suitability for specialized industrial heat transfer equipment, and critically, its outside diameter falling strictly between 190.5 mm and 285.8 mm. Importers should verify these physical and functional attributes to ensure accurate classification.