3810.90 - Other:

This HTS category, 3810.90, encompasses a diverse range of auxiliary preparations and materials used in metal surface treatment and joining processes, excluding specific pickling preparations and certain readily identifiable soldering/brazing powders and pastes. It covers fluxes and other auxiliary preparations designed to facilitate soldering, brazing, or welding, which may include binders, activators, and other chemical components. Additionally, it captures soldering, brazing, or welding powders and pastes that do not fall under the specific compositional criteria of sibling category 3810.10.

The primary distinction between 3810.90 and its sibling, 3810.10, lies in the specificity of the product. While 3810.10 is reserved for pickling preparations and powders/pastes with specific metal content, 3810.90 captures a broader spectrum of fluxes and auxiliary preparations that are not exclusively pickling agents and may have more complex compositions or varied applications beyond simple powder or paste forms. This category acts as a residual for welding-related preparations not otherwise specified.

The subcategories within 3810.90 provide further refinement based on the chemical composition of the preparations. 3810.90.10.00 specifically addresses preparations containing a significant proportion (5% or more by weight) of aromatic or modified aromatic substances, often used as binders or to impart specific fluxing properties. Category 3810.90.20.00 isolates preparations consisting entirely of inorganic substances, such as certain metal salts or oxides, utilized for their fluxing or protective capabilities. Finally, 3810.90.50.00 serves as a catch-all for any remaining auxiliary preparations and powders/pastes that do not fit the specific criteria of the preceding subcategories.