7306.19.51.10 - With an outside diameter not exceeding 114.3 mm

This HTS category, 7306.19.51.10, specifically covers line pipe made of alloy steel that is used for oil or gas pipelines, and importantly, has an outside diameter *not exceeding 114.3 mm*. These pipes are characterized by their construction and intended application in transporting hydrocarbons, distinguishing them from general-purpose steel pipes. The alloy steel composition signifies a material with added elements beyond iron and carbon to enhance properties like strength, corrosion resistance, or temperature tolerance, crucial for demanding pipeline environments.

The primary distinguishing factor for this subcategory, compared to its sibling 7306.19.51.50, lies solely in the physical dimension of the outside diameter. While both are alloy steel line pipe for oil and gas, this classification applies to those with diameters 114.3 mm or less, whereas the sibling encompasses those exceeding this threshold. This precise diameter distinction is a critical criterion for accurate tariff classification.

As this node represents a leaf node in the HTS structure, there are no further subcategories to introduce. Therefore, classification within this code relies entirely on the confirmation of the material (alloy steel), the intended use (oil or gas pipelines), and the specified outside diameter not exceeding 114.3 mm. Importers and exporters must ensure their goods precisely meet all these criteria to apply this tariff code correctly.