7306.21.30.00 - Threaded or coupled

This HTS classification, 7306.21.30.00, specifically covers threaded or coupled casing and tubing of iron or steel, of the kind used in drilling for oil or gas, and manufactured from welded stainless steel. The defining characteristic of this subcategory is the method of joining or preparing the ends of the pipes for assembly. "Threaded or coupled" signifies that these pipes are equipped with pre-formed threads on their ends to facilitate screwing them together, or they are designed to accept couplings, which are separate connecting pieces that are then attached to the pipe ends. This applies to casing (larger diameter pipes used to line the wellbore) and tubing (smaller diameter pipes used to bring oil or gas to the surface) where this specific end treatment is present.

Distinguishing this category from its sibling, 7306.21.40.00 ("Other"), is crucial. The "Other" category would encompass welded stainless steel casing and tubing for oil and gas drilling that are *not* threaded or coupled at the end. This could include pipes prepared for welding by the importer, or those intended for other joining methods not explicitly defined as threaded or coupled. Therefore, the presence or absence of pre-made threads or provision for couplings is the key differentiator between these two sibling classifications.

As a leaf node, this classification does not have further subcategories. Its scope is precise, encompassing only welded stainless steel casing and tubing for oil and gas drilling that features threaded or coupled ends. Importers and exporters should carefully examine the physical characteristics of their goods to ensure accurate classification, verifying the material (stainless steel), the manufacturing method (welded), the intended use (oil and gas drilling), and the specific end-preparation (threaded or coupled).