7304.90.10.00 - Of iron or nonalloy steel

This classification covers seamless tubes, pipes, and hollow profiles made from iron or non-alloy steel, where the wall thickness is 4 millimeters or more. These articles are characterized by their seamless construction, meaning they are formed without a welded seam, and their composition of iron or steel that does not contain significant alloying elements beyond those inherent to standard steel production. Examples include heavy-duty structural pipes, oil and gas transmission pipelines with substantial wall thickness, and large-diameter industrial conduits manufactured from non-alloy steel.

This category is distinct from its sibling, 7304.90.30.00, which specifically classifies similar seamless tubes, pipes, and hollow profiles when made of *alloy steel*. The key differentiating factor is the material composition; this category is reserved for non-alloy steel, whereas the sibling category applies to steel containing specified amounts of one or more alloying elements. Therefore, determining whether the steel contains alloying elements beyond standard specifications is crucial for correct classification.

As this is a leaf node in the HTS classification system, there are no further subcategories. Classification under this code is definitive once the criteria of being seamless, made of iron or non-alloy steel, and having a wall thickness of 4 mm or more are met.