Product classification
HS code for Brazing flux: 3810.90
Fluxes and other auxiliary preparations, for soldering, brazing or welding, or preparations used as cores or coatings for welding electrodes or rods.
Classification of brazing flux under HS 3810.90
Brazing flux is classified under HS code 3810.90. This code falls within Chapter 38, which covers miscellaneous chemical products. Specifically, heading 3810 includes pickling preparations for metal surfaces and fluxes and other auxiliary preparations for soldering, brazing, or welding. Brazing flux is a chemical agent used to prevent oxidation during the joining of metals and to facilitate the flow of the filler metal. The subheading 3810.90 is a residual category for preparations other than those used for pickling metal or as cores/coatings for welding electrodes. These preparations can be in the form of powders, pastes, or liquids. The classification is determined by the chemical composition and the specific industrial application of the product in the metal-joining process.
- Covers
- Silver brazing flux powder
- Aluminum brazing flux paste
- Fluoride-based brazing fluxes
- Borax-based flux preparations
- Liquid flux for torch brazing
- Also under 3810.90
- Kester Flux
- Alpha Assembly Solutions Flux
- Indium Corporation Flux
- Lincoln Electric Flux
- ESAB Welding Flux
Codes often confused with 3810.90
Common mistake. Brazing flux is often confused with HS code 3810.10, which is strictly for pickling preparations for metal surfaces (acidic solutions used to clean metal). Another common error is attempting to classify the flux under the HS code of the filler metal (such as silver solder in Chapter 71 or copper alloys in Chapter 74). However, chemical preparations used as fluxes must remain in Chapter 38. Additionally, welding electrodes that already contain flux as a core or coating are classified under 8311.
Top exporters and importers of HS 381090 (the code used for brazing flux), 2025
In 2025, the largest exporter of HS 381090 (the code used for brazing flux) in UN Comtrade data was Germany, with 18% of world exports; the largest importer in UN Comtrade data was China, with 11% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 381090, not only brazing flux.
Top exporters 2025 · share of world exports
- 1 Germany $164M 18% of world exports
- 2 Japan $159M 17% of world exports
- 3 China $86M 9.4% of world exports
World total: $921M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 China $120M 11% of world imports
- 2 Malaysia $105M 9.7% of world imports
- 3 Philippines $78M 7.2% of world imports
World total: $1.1B Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for brazing flux
Brazil classifies brazing flux under NCM 3810.90.00: HS 3810.90 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about brazing flux
What is the HS code for Brazing flux?
The HS code for Brazing flux is 381090 (Fluxes and other auxiliary preparations; for soldering, brazing or welding, or preparations used as cores or coatings for welding electrodes or rods). The HS code for brazing flux and similar auxiliary preparations is 3810.90.
How do I classify Brazing flux for customs?
Brazing flux is classified under HS code 381090 — Fluxes and other auxiliary preparations; for soldering, brazing or welding, or preparations used as cores or coatings for welding electrodes or rods. This is a 6-digit subheading level code.
Is solder wire with a flux core classified here?
No, solder wire with a flux core is typically classified under heading 8311 as wire or rods of base metal for soldering or welding.
Which countries are the top exporters of brazing flux (HS 381090)?
In 2025, the top exporters of HS 381090 (the code used for brazing flux) in UN Comtrade data were Germany ($164M, 18% of world exports), Japan ($159M) and China ($86M). World exports came to about $921M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of brazing flux (HS 381090)?
In 2025, the top importers of HS 381090 (the code used for brazing flux) in UN Comtrade data were China ($120M, 11% of world imports), Malaysia ($105M) and the Philippines ($78M). World imports came to about $1.1B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Is the HS code for Brazing flux the same in all countries?
The base HS code 381090 for Brazing flux is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for brazing flux in Brazil?
In Brazil, brazing flux (HS 381090) is classified under NCM 3810.90.00.