7305.31.60 - Of alloy steel

This HTS category, 7305.31.60, specifically classifies longitudinally welded tubes and pipes of iron or steel that exceed 406.4 mm in external diameter. These are articles of base metal, falling within Section XV, Chapter 73, and are distinguished by their welded construction, circular cross-section, and large diameter, which sets them apart from smaller diameter pipes or those with different welding methods.

Within this subcategory, the critical differentiator is the material composition, as indicated by the "Of alloy steel" description. This distinguishes it from its sibling category, 7305.31.40.00, which is designated for tubes and pipes made of iron or non-alloy steel. Therefore, the presence of specific alloying elements in the steel is the determining factor for classification under 7305.31.60.

Further refinement of this classification is provided by its subcategories. 7305.31.60.10 covers tubes and pipes specifically manufactured from stainless steel, a common and distinct type of alloy steel. The remaining alloy steel products not meeting the stainless steel criteria will fall under the residual category, 7305.31.60.90, allowing for comprehensive coverage of all alloy steel longitudinally welded pipes exceeding the specified diameter.