Product classification
HS code for Carbon steel flanges: 7307.91
Iron or steel, tube or pipe fittings, flanges, other than stainless steel.
Classification of carbon steel flanges under HS 7307.91
Carbon steel flanges are classified under HS code 7307.91. This classification is determined by the product's specific function as a flange and its material composition. Under the Harmonized System, heading 7307 covers tube or pipe fittings of iron or steel. The subheadings are organized to distinguish between cast and non-cast products, and then by material type. Flanges made of iron or non-alloy steel (carbon steel) are explicitly provided for in subheading 7307.91. A flange is defined as a projecting rim, collar, or ring used to connect pipe sections or to attach a pipe to a valve, pump, or other equipment. These are typically bolted together with a gasket in between to create a sealed, yet detachable, joint. The material must meet the definition of non-alloy steel found in Chapter 72, Note 1(f), ensuring it does not contain alloying elements above specified weight percentages. These flanges are commonly manufactured to standards such as ASME B16.5 or EN 1092-1 and are used extensively in high-pressure piping systems across the energy and manufacturing sectors.
- Covers
- Carbon steel slip-on flanges
- Weld neck flanges (non-stainless)
- Blind flanges for pipe termination
- Socket weld and lap joint flanges
- Threaded carbon steel flanges
- Also under 7307.91
- Forged Components Inc. carbon steel flanges
- Galperti carbon steel flanges
- Ulma Piping carbon steel flanges
- Tenaris carbon steel flanges
Codes often confused with 7307.91
Common mistake. Carbon steel flanges are often misclassified under 7307.21, which is the specific code for stainless steel flanges. Importers must verify the chemical mill test report (MTR) to ensure the chromium content is below 10.5%. Another error involves 7307.11 or 7307.19, which are for cast iron or cast steel fittings. While many flanges start as castings, if they are subsequently forged or heavily machined, they are generally classified under 7307.91. Finally, some users confuse these with structural plates under 7208, but once a plate is worked into a flange shape, it must be classified under 7307.
Top exporters and importers of HS 730791 (the code used for carbon steel flanges), 2025
In 2025, the largest exporter of HS 730791 (the code used for carbon steel flanges) in UN Comtrade data was China, with 32% of world exports; the largest importer in UN Comtrade data was the United States, with 15% 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 730791, not only carbon steel flanges.
Top exporters 2025 · share of world exports
- 1 China $703M 32% of world exports
- 2 Italy $357M 16% of world exports
- 3 India $267M 12% of world exports
World total: $2.2B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $366M 15% of world imports
- 2 Saudi Arabia $163M 6.8% of world imports
- 3 Germany $134M 5.6% of world imports
World total: $2.4B 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 carbon steel flanges
Brazil classifies carbon steel flanges under NCM 7307.91.00: HS 7307.91 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
EU Regulatory Requirements
This product falls under the Carbon Border Adjustment Mechanism (CBAM). Importers to the EU must declare embedded carbon emissions and purchase CBAM certificates.
Questions about carbon steel flanges
What is the HS code for Carbon steel flanges?
The HS code for Carbon steel flanges is 730791 (Iron or steel; tube or pipe fittings, flanges, other than stainless steel). The HS code for flanges made of iron or non-alloy steel (carbon steel) is 7307.91.
How do I classify Carbon steel flanges for customs?
Carbon steel flanges is classified under HS code 730791 — Iron or steel; tube or pipe fittings, flanges, other than stainless steel. This is a 6-digit subheading level code.
Are galvanized carbon steel flanges classified differently?
No, the application of a zinc coating (galvanization) does not change the HS code; they remain under 7307.91 as long as the base material is carbon steel.
Which countries are the top exporters of carbon steel flanges (HS 730791)?
In 2025, the top exporters of HS 730791 (the code used for carbon steel flanges) in UN Comtrade data were China ($703M, 32% of world exports), Italy ($357M) and India ($267M). World exports came to about $2.2B, 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 carbon steel flanges (HS 730791)?
In 2025, the top importers of HS 730791 (the code used for carbon steel flanges) in UN Comtrade data were the United States ($366M, 15% of world imports), Saudi Arabia ($163M) and Germany ($134M). World imports came to about $2.4B, 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 Carbon steel flanges the same in all countries?
The base HS code 730791 for Carbon steel flanges 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 carbon steel flanges in Brazil?
In Brazil, carbon steel flanges (HS 730791) is classified under NCM 7307.91.00.