HS code · 6-digit subheading
HS Code 7318.21 – Iron or steel; non-threaded spring washers and other lock washers
HS code 7318.21 is the 6-digit subheading for iron or steel, non-threaded spring washers and other lock washers. It is used for split lock washers, external tooth lock washers, internal tooth lock washers, conical spring washers and wave washers.
What HS 7318.21 covers
This category covers non-threaded washers specifically designed to prevent loosening of bolted joints due to vibration, thermal expansion, or dynamic loads. Spring washers, with their inherent elasticity, and various lock washers, which create friction or a mechanical lock, are critical components in ensuring the long-term integrity and safety of assemblies across numerous industries. They are essential in maintaining the preload of a bolted joint, thereby preventing catastrophic failures. International trade in these items is driven by global manufacturing, particularly in automotive, aerospace, heavy machinery, and construction sectors where fastener reliability is paramount. Importers are typically assembly plants, MRO suppliers, and hardware distributors. Exporters are specialized manufacturers of industrial fasteners and components, often leveraging advanced material science and precision engineering to meet stringent performance requirements. Key considerations for trade include material grade (e.g., carbon steel, stainless steel), finish (e.g., zinc plated, phosphated), specific design (e.g., split lock, external tooth, internal tooth), and compliance with international standards like DIN and ANSI.
- Covers
- Split lock washers
- External tooth lock washers
- Internal tooth lock washers
- Conical spring washers
- Wave washers
- Belleville washers
- Serrated lock washers
- Examples
- Nord-Lock washers
- Schnorr disc springs
- Fastenal lock washers
- Würth spring washers
Codes often confused with 7318.21
Common mistake. Can be confused with 731822 (other non-threaded washers) if the locking or spring function is not clearly identified, as 731821 specifically covers those designed for locking.
Top exporters and importers of HS code 731821, 2025
In 2025, the largest exporter of HS code 731821 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.
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 7318.21
Brazil does not split HS 7318.21: its NCM code is 7318.21.00.
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 7318.21
What is HS code 731821?
HS code 731821 is a 6-digit subheading in the Harmonized System that covers: Iron or steel; non-threaded spring washers and other lock washers. This category covers non-threaded washers specifically designed to prevent loosening of bolted joints due to vibration, thermal expansion, or dynamic loads. Spring washers, with their inherent elasticity, and various lock washers, which create friction or a mechanical lock, are critical components in ensuring the long-term integrity and safety of assemblies across numerous industries. They are essential in maintaining the preload of a bolted joint, thereby preventing catastrophic failures. International trade in these items is driven by global manufacturing, particularly in automotive, aerospace, heavy machinery, and construction sectors where fastener reliability is paramount. Importers are typically assembly plants, MRO suppliers, and hardware distributors. Exporters are specialized manufacturers of industrial fasteners and components, often leveraging advanced material science and precision engineering to meet stringent performance requirements. Key considerations for trade include material grade (e.g., carbon steel, stainless steel), finish (e.g., zinc plated, phosphated), specific design (e.g., split lock, external tooth, internal tooth), and compliance with international standards like DIN and ANSI.
What products fall under HS code 731821?
Split lock washers, external tooth lock washers, internal tooth lock washers, conical spring washers, wave washers, Belleville washers, serrated lock washers
What are common misclassifications for HS code 731821?
Can be confused with 731822 (other non-threaded washers) if the locking or spring function is not clearly identified, as 731821 specifically covers those designed for locking.
Which countries are the top exporters of goods under HS code 731821?
In 2025, the top exporters of HS code 731821 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 goods under HS code 731821?
In 2025, the top importers of HS code 731821 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.
How is HS code 731821 structured?
HS code 731821 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 (21) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 731821?
In Brazil, HS code 731821 is NCM 7318.21.00. The last two digits are 00 because Brazil does not split this HS code further.