Product classification
HS code for Steel nuts: 7318.16
Iron or steel, threaded nuts.
Classification of steel nuts under HS 7318.16
Steel nuts are classified under HS code 731816 because they fall within the broader category of screws, bolts, nuts, coach screws, screw hooks, rivets, cotters, cotter-pins, washers, and similar articles of iron or steel. Specifically, heading 7318 is divided into threaded and non-threaded articles. Since nuts are inherently threaded components designed to mate with a bolt or screw to fasten parts together, they are categorized under the threaded section. Subheading 731816 is the specific international designation for threaded nuts made of iron or steel. The classification is determined by the physical characteristic of internal threading and the material composition of ferrous metal. This code is used globally to track the trade of fasteners that provide clamping force in mechanical assemblies, construction, and automotive manufacturing. It is important to note that this code applies regardless of the nut's shape or specific locking mechanism, provided the primary material is iron or steel and it features internal threads.
- Covers
- Hexagonal nuts (hex nuts)
- Square nuts
- Wing nuts
- Lock nuts (including nylon insert nuts)
- Flange nuts
- Cap nuts (acorn nuts)
- Slotted nuts and castle nuts
- Coupling nuts
- Also under 7318.16
- Nord-Lock washers (used with nuts)
- Fastenal hex nuts
- Würth self-locking nuts
- Böllhoff rivet nuts
Codes often confused with 7318.16
Common mistake. Steel nuts are frequently confused with other fasteners in the 7318 heading. A common error is classifying them under 731815, which is reserved for bolts and screws; while they are often sold together, they must be classified separately. Another misclassification occurs with 731822, which covers non-threaded washers. If a nut is made of stainless steel, some jurisdictions may require classification under specific stainless steel subheadings, though 731816 remains the primary global standard for threaded steel nuts. Additionally, nuts made of copper alloys must be moved to chapter 74.
Top exporters and importers of HS 731816 (the code used for steel nuts), 2025
In 2025, the largest exporter of HS 731816 (the code used for steel nuts) in UN Comtrade data was China, with 20% of world exports; the largest importer in UN Comtrade data was the United States, with 17% 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 731816, not only steel nuts.
Top exporters 2025 · share of world exports
- 1 China $1.7B 20% of world exports
- 2 Taiwan* ~$1.2B 15% of world exports · partner records ↗
- 3 United States $1.2B 14% of world exports
World total: $8.3B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 United States $1.4B 17% of world imports
- 2 Germany $777M 9.7% of world imports
- 3 Mexico $492M 6.1% of world imports
World total: $8.0B 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 marked * did not, so their figures add up what other countries recorded trading with them, and their exports are valued at buyers' CIF prices. 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. UN Comtrade records Taiwan as "Other Asia, not elsewhere specified". Saudi Arabia's exports under that code are left out: they are far too large to be trade with Taiwan, so mostly undisclosed partners. 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 steel nuts
Brazil classifies steel nuts under NCM 7318.16.00: HS 7318.16 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 steel nuts
What is the HS code for Steel nuts?
The HS code for Steel nuts is 731816 (Iron or steel; threaded nuts). The primary HS code for threaded nuts made of iron or steel is 731816.
How do I classify Steel nuts for customs?
Steel nuts is classified under HS code 731816 — Iron or steel; threaded nuts. This is a 6-digit subheading level code.
Does this code include stainless steel nuts?
Yes, 731816 generally covers threaded nuts of iron or steel, including stainless varieties, although some regional tariffs may provide specific statistical suffixes for stainless steel grades.
Which countries are the top exporters of steel nuts (HS 731816)?
In 2025, the top exporters of HS 731816 (the code used for steel nuts) in UN Comtrade data were China ($1.7B, 20% of world exports), Taiwan (about $1.2B) and the United States ($1.2B). World exports came to about $8.3B, 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 steel nuts (HS 731816)?
In 2025, the top importers of HS 731816 (the code used for steel nuts) in UN Comtrade data were the United States ($1.4B, 17% of world imports), Germany ($777M) and Mexico ($492M). World imports came to about $8.0B, 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 Steel nuts the same in all countries?
The base HS code 731816 for Steel nuts 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 steel nuts in Brazil?
In Brazil, steel nuts (HS 731816) is classified under NCM 7318.16.00.