HS code · 6-digit subheading
HS Code 7318.16 – Iron or steel; threaded nuts
HS code 7318.16 is the 6-digit subheading for iron or steel, threaded nuts. It is used for hex nuts, lock nuts, wing nuts, cap nuts and flange nuts.
What HS 7318.16 covers
This code covers a vast array of threaded nuts made from iron or steel, crucial components in almost every assembly requiring a secure fastening. These nuts are designed to mate with threaded bolts or screws, providing clamping force and preventing loosening in a multitude of applications, from heavy machinery to consumer electronics. International trade in these items is driven by global manufacturing supply chains, with demand stemming from automotive, aerospace, construction, and general engineering sectors. Importers typically include assembly plants, hardware wholesalers, and MRO (Maintenance, Repair, and Operations) suppliers who require a steady supply for production and maintenance. Exporters are specialized fastener manufacturers, often located in regions with strong steel production capabilities and advanced manufacturing processes. Key considerations for trade involve material strength, thread pitch, plating (e.g., zinc, hot-dip galvanized for corrosion protection), and adherence to international standards like ISO, DIN, and ANSI, which ensure compatibility and performance across different markets. The sheer volume and variety make this a significant segment of the industrial hardware market.
- Covers
- Hex nuts
- Lock nuts
- Wing nuts
- Cap nuts
- Flange nuts
- Coupling nuts
- Square nuts
- Castle nuts
- Examples
- Nord-Lock washers (used with nuts)
- Fastenal hex nuts
- Würth self-locking nuts
- Böllhoff rivet nuts
Codes often confused with 7318.16
Common mistake. Often confused with 731815 (screws and bolts) or 731819 (other threaded articles), but 731816 is specifically for threaded nuts, not the bolts or screws they attach to.
Top exporters and importers of HS code 731816, 2025
In 2025, the largest exporter of HS code 731816 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.
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 7318.16
Brazil does not split HS 7318.16: its NCM code is 7318.16.00.
All Brazil NCM codes in heading 73.18 →
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text is official; the English is our translation.
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 HS 7318.16
What is HS code 731816?
HS code 731816 is a 6-digit subheading in the Harmonized System that covers: Iron or steel; threaded nuts. This code covers a vast array of threaded nuts made from iron or steel, crucial components in almost every assembly requiring a secure fastening. These nuts are designed to mate with threaded bolts or screws, providing clamping force and preventing loosening in a multitude of applications, from heavy machinery to consumer electronics. International trade in these items is driven by global manufacturing supply chains, with demand stemming from automotive, aerospace, construction, and general engineering sectors. Importers typically include assembly plants, hardware wholesalers, and MRO (Maintenance, Repair, and Operations) suppliers who require a steady supply for production and maintenance. Exporters are specialized fastener manufacturers, often located in regions with strong steel production capabilities and advanced manufacturing processes. Key considerations for trade involve material strength, thread pitch, plating (e.g., zinc, hot-dip galvanized for corrosion protection), and adherence to international standards like ISO, DIN, and ANSI, which ensure compatibility and performance across different markets. The sheer volume and variety make this a significant segment of the industrial hardware market.
What products fall under HS code 731816?
Hex nuts, lock nuts, wing nuts, cap nuts, flange nuts, coupling nuts, square nuts, castle nuts
What are common misclassifications for HS code 731816?
Often confused with 731815 (screws and bolts) or 731819 (other threaded articles), but 731816 is specifically for threaded nuts, not the bolts or screws they attach to.
Which countries are the top exporters of goods under HS code 731816?
In 2025, the top exporters of HS code 731816 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 goods under HS code 731816?
In 2025, the top importers of HS code 731816 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.
How is HS code 731816 structured?
HS code 731816 is a 6-digit subheading under the Harmonized System. The first 2 digits (73) identify the chapter, digits 3-4 (18) identify the heading, and digits 5-6 (16) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 731816?
In Brazil, HS code 731816 is NCM 7318.16.00. The last two digits are 00 because Brazil does not split this HS code further.