2524.90.00.45 - Milled fibers, group 4 and 5 grades

This HTS category, 2524.90.00.45, specifically classifies milled asbestos fibers that fall within group 4 and group 5 grades. These are generally understood to be processed forms of asbestos, further refined beyond basic milling, and intended for applications that require specific fiber characteristics. The "group 4 and 5 grades" designation typically refers to a grading system based on fiber length, fineness, and spinning potential, with these grades representing finer and more specialized classifications than lower-numbered groups.

This classification is distinct from its siblings, primarily by the specific grade of milled fibers it represents. For instance, it differentiates from 2524.90.00.40, which covers milled fibers designated as group 3 grades, often referred to as spinning fibers or equivalent. Group 3 fibers generally possess characteristics suitable for direct spinning into asbestos yarn or thread. Conversely, group 4 and 5 grades in this category may be used in more specialized applications where different physical properties are paramount, such as in certain composites, friction materials, or insulation products where the emphasis is less on direct spinning and more on bulk properties or fine dispersion.

As this is a leaf node within the HTS structure, there are no further subcategories. Therefore, classification into 2524.90.00.45 hinges on confirming that the milled asbestos fibers in question meet the established criteria for group 4 and group 5 grades, distinguishing them from other milled fiber grades. Importers and exporters should consult technical specifications or grading certificates to ensure accurate classification based on the physical properties and intended use of the specific asbestos fibers being imported or exported.