7307.91.50.70 - Of alloy steel (except stainless steel)

This HTS category, 7307.91.50.70, specifically classifies flanges made of iron or steel that have an inside diameter of 360 millimeters or more. These fittings are essential components in piping systems, used to connect pipes, valves, pumps, and other equipment to form a system. They are designed to provide a leak-proof seal and are typically bolted together to create a robust connection.

This classification distinguishes itself from its sibling category, 7307.91.50.50, by its material composition. While 7307.91.50.50 covers flanges of iron or non-alloy steel, this category, 7307.91.50.70, is reserved for flanges manufactured from alloy steel, excluding stainless steel. The inclusion of alloying elements in these steels imparts specific properties, such as increased strength, hardness, or resistance to certain environmental conditions, that differentiate them from standard iron or non-alloy steel.

As this is a leaf node within the HTS structure, there are no further subcategories to detail. The classification hinges on the specific combination of the item being a flange, its substantial size (inside diameter of 360 mm or more), and its composition of alloy steel (excluding stainless steel). This precise delineation ensures accurate categorization for customs purposes.