8455.90 - Other parts:

Heading 8455 pertains to metal-rolling mills and their constituent rolls, along with any parts thereof. This specific subcategory, 8455.90, encompasses all parts of metal-rolling mills that are not specifically covered by other headings within 8455. This includes components such as housings, frames, drive mechanisms, cooling systems, and other ancillary equipment designed for use with metal-rolling mill machinery.

This category serves as a residual classification for parts. It is distinct from sibling categories such as 8455.10, which specifically covers tube mills, and 8455.30, which exclusively covers the rolls themselves used in rolling mills. Therefore, 8455.90 is for all other components essential to the operation of metal-rolling mills that do not fall under these more specific classifications.

The subcategories within 8455.90 further refine the classification of these parts. 8455.90.40.00 is designated for castings or weldments, provided they individually weigh less than 90 tons, and are intended for use in the machines of heading 8455. All other remaining parts of metal-rolling mills, not meeting the criteria for 8455.90.40.00 or any other more specific part classification, fall under the residual category 8455.90.80.00.