Product classification
HS code for Lock washers: 7318.21
Iron or steel, non-threaded spring washers and other lock washers.
Classification of lock washers under HS 7318.21
Lock washers are classified under HS code 7318.21. This classification falls within Chapter 73, which covers articles of iron or steel. Heading 7318 is specifically for screws, bolts, nuts, coach screws, screw hooks, rivets, cotters, cotter-pins, washers (including spring washers) and similar articles. Subheading 7318.21 is a specific breakout for spring washers and other lock washers that are non-threaded. The primary characteristic for this classification is the washer's design to prevent a fastener from loosening under vibration or torque. This is achieved through spring tension or serrated surfaces. The classification is straightforward under GRI 1, as the product name and function align perfectly with the subheading text. It is important to note that this code only applies to washers made of iron or steel; washers made of copper or aluminum would be classified in their respective chapters (Chapter 74 or 76).
- Covers
- Split-ring lock washers (helical)
- Internal and external tooth star washers
- Serrated lock washers
- Wave washers designed for locking
- Belleville washers (when used as spring washers)
- Nord-Lock style wedge-locking washers
- Also under 7318.21
- Nord-Lock washers
- Schnorr disc springs
- Fastenal lock washers
- Würth spring washers
Codes often confused with 7318.21
Common mistake. The most frequent misclassification for lock washers is HS code 7318.22, which covers 'other' non-threaded washers that do not have a spring or locking function (standard flat washers). Another error occurs when lock washers are imported as part of a kit; if they are packaged with bolts and nuts, they might be incorrectly classified under 7318.15. However, when shipped as individual components, the distinction between a spring/lock washer (7318.21) and a plain washer (7318.22) is critical for accurate duty application.
Top exporters and importers of HS 731821 (the code used for lock washers), 2025
In 2025, the largest exporter of HS 731821 (the code used for lock washers) in UN Comtrade data was Germany, with 29% of world exports; the largest importer in UN Comtrade data was Germany, 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 731821, not only lock washers.
Top exporters 2025 · share of world exports
- 1 Germany $263M 29% of world exports
- 2 United States $100M 11% of world exports
- 3 China $85M 9.3% of world exports
World total: $921M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Germany $115M 11% of world imports
- 2 United States $83M 8.3% of world imports
- 3 Mexico $80M 7.9% of world imports
World total: $1.0B 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 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 lock washers
Brazil classifies lock washers under NCM 7318.21.00: HS 7318.21 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 lock washers
What is the HS code for Lock washers?
The HS code for Lock washers is 731821 (Iron or steel; non-threaded spring washers and other lock washers). The HS code for iron or steel lock washers and spring washers is 7318.21.
How do I classify Lock washers for customs?
Lock washers is classified under HS code 731821 — Iron or steel; non-threaded spring washers and other lock washers. This is a 6-digit subheading level code.
Are stainless steel lock washers classified differently?
No, stainless steel is a type of steel, so stainless steel lock washers are still classified under HS code 7318.21.
Which countries are the top exporters of lock washers (HS 731821)?
In 2025, the top exporters of HS 731821 (the code used for lock washers) in UN Comtrade data were Germany ($263M, 29% of world exports), the United States ($100M) and China ($85M). 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 lock washers (HS 731821)?
In 2025, the top importers of HS 731821 (the code used for lock washers) in UN Comtrade data were Germany ($115M, 11% of world imports), the United States ($83M) and Mexico ($80M). World imports came to about $1.0B, 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 Lock washers the same in all countries?
The base HS code 731821 for Lock washers 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 lock washers in Brazil?
In Brazil, lock washers (HS 731821) is classified under NCM 7318.21.00.