8455.21.00.00 - Hot or combination hot and cold 🖩

This HTS category, 8455.21.00.00, specifically covers metal-rolling mills and their associated rolls that are designed for **hot rolling** or a **combination of hot and cold rolling** processes. These machines are integral to the metal manufacturing industry, where they shape metal ingots, slabs, or billets into finished or semi-finished products such as sheets, plates, bars, and structural shapes. The key distinguishing feature of this classification is the capability of the mill to perform operations at elevated temperatures, either exclusively or in conjunction with cold rolling.

It is important to differentiate this category from its sibling, 8455.22.00.00, which exclusively covers metal-rolling mills designed for **cold rolling**. While both categories pertain to metal-rolling machinery, the operational temperature is the critical factor for classification. Mills classified under 8455.21.00.00 are equipped to handle the thermal stresses and material properties associated with hot metal processing, whereas cold rolling mills operate at ambient temperatures to achieve tighter tolerances and specific surface finishes.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification within 8455.21.00.00 is determined by the presence of hot or combined hot and cold rolling capabilities. Importers and exporters should ensure that the functionality of their metal-rolling machinery aligns with the described hot-working or dual-process capability to ensure accurate tariff classification.