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Taiwan Rep / Notes

One hex bolt, three tariff codes: why the HS code on a Taiwan invoice isn't your import code

Taiwan, the US and the EU all start a steel hex bolt at 7318.15. After those six digits they split it in different ways. Taiwan's code doesn't record the details the other two care about: in the US, whether a hex head of 6 mm or more has a washer face, which can move the general duty from Free to 8.5%, and in the EU, whether a non-stainless hex screw or bolt reaches 800 MPa tensile strength.

Updated October 13, 2026. US lines from the USITC's HTS service, Taiwan lines from the Customs Administration's tariff file, EU codes and 2025 tonnages from Eurostat, all read that day.

The short version

  • Only the first six digits are international. The digits after 7318.15 are set by each customs territory, so the code on your supplier's export papers can't simply be copied onto your import entry.
  • Taiwan's file has 13 lines for the whole of heading 7318. Every screw and bolt in subheading 7318.15 that isn't for railway track goes into one code, 7318.15.90.00-7.
  • The US separates bolts (7318.15.20, general duty Free) from screws, including cap screws (7318.15.80, 8.5% at 6 mm and up). CBP has treated a hex fastener with a washer face, or chamfered corners on the underside of the head, as a cap screw, and it doesn't go by ISO standard names.
  • The EU doesn't care whether a hex fastener is a bolt or a screw. It splits non-stainless hex screws and bolts at a tensile strength of 800 MPa.
  • Section 232 applies to every steel 7318 line, so for ordinary Taiwan fasteners the code doesn't change that 50%. It does change the regular duty underneath it.

When a Taiwan quote or export document carries a tariff code, it's tempting to treat it as settled. The Harmonized System is international, and a hex bolt is a hex bolt. But the shared part stops at six digits. Taiwan, the US and the EU each add their own digits after that (the EU's are common to all member states), and they split the same bolt on different features. This note covers what the shared six digits say, how Taiwan's own code compares, what decides the US line and its duty, what decides the EU line, and what to get on the invoice so your broker can classify the goods.

The six digits everyone shares

Heading 7318 covers screws, bolts, nuts, coach screws, screw hooks, rivets, cotters, cotter pins, washers and similar articles of iron or steel. At six digits it splits threaded articles (7318.11 to .19) from non-threaded ones (7318.21 to .29), and within threaded articles it separates coach screws, wood screws, screw hooks, self-tapping screws, other screws and bolts (7318.15), nuts (7318.16) and other threaded articles (7318.19). Those six digits mean the same thing in Taipei, Washington and Brussels.

Taiwan stops close to there. Its Customs Administration publishes the tariff as open data, with one row per 11-digit code. Under 7318 there are 13 rows, and 7318.15 has only two:

Taiwan codeDescription in the tariff file
7318.15.10.00-4Screws and bolts for rail, whether or not with their nuts or washers, of iron or steel
7318.15.90.00-7Other screws and bolts, whether or not with their nuts or washers, of iron or steel

The same row also carries codes for Taiwan's import and export requirements, which is where the restriction codes for Chinese goods in our import rules note appear. So an ordinary hex bolt, socket cap screw, stainless flange bolt or carriage bolt generally goes out of Taiwan under 7318.15.90.00-7. The code records none of the features that decide your import line: head type, washer face, stainless or not, tensile strength, diameter. That information has to come from the product description and the supplier's drawings and certificates.

In the US: bolt or cap screw, Free or 8.5%

The US splits 7318.15 much more finely, and two of the splits move the duty. These are the Column 1 general rates in the Harmonized Tariff Schedule for the main eight-digit lines (entries use ten-digit statistical numbers under them):

US subheadingGoodsGeneral rate
7318.15.20Bolts, and bolts with their nuts or washers in the same shipmentFree
7318.15.40Machine screws 9.5 mm or more long and 3.2 mm or more in diameter (not cap screws)Free
7318.15.50Studs, including continuously threaded rodFree
7318.15.60Other screws, shank or thread under 6 mm6.2%
7318.15.80Other screws, shank or thread 6 mm or more (statistical lines for set screws, socket screws, hex cap screws and others)8.5%
7318.16.00NutsFree

So the question that matters for a hex fastener of 6 mm or more is whether it is a bolt or a screw. The tariff doesn't define either word. CBP's informed compliance publication on distinguishing bolts from screws says it uses the Specification for Identification of Bolts and Screws in ANSI-ASME B18.2.1 (1981). The Court of International Trade endorsed that in Rocknel Fastener v. United States (2000) and said the specification applies to metric fasteners too. In short, a bolt is designed to go through holes and normally be tightened by turning a nut, and a screw is designed to mate with a preformed internal thread or form its own, and be tightened by turning its head. Using a screw with a nut doesn't make it a bolt.

For hex heads, CBP has a simpler test. Its publication on fasteners of heading 7318 says that a fastener with a washer face or its equivalent on the underside of the head is a cap screw, and that chamfered corners on the underside of a hex head count as the equivalent. That rule goes back to the Heads and Threads cases of 1968 and 1969. In a 2010 internal advice ruling (HQ H095040), an importer had entered hex fasteners it called "hex tap bolts" as bolts and argued they met ISO standards for bolts. CBP classified the samples without a washer face as bolts under 7318.15.20 and the ones with a washer face as screws under 7318.15.80. It also noted that the court in Rocknel hadn't adopted the importer's argument for ISO standards; CBP's publication cites this ruling and an earlier one, HQ 959280, as rejecting ISO standards for telling bolts from screws.

The practical point: "hex bolt" on a Taiwan invoice, or an ISO bolt standard number, doesn't settle the US line. For hex fasteners like the ones in that ruling, the underside of the head was decisive; other designs are still judged against the full criteria and rulings.

What does the difference cost? A hypothetical: zinc-plated steel M12 hex fasteners from Taiwan with a customs value of $40,000. Section 232 applies to every steel 7318 line at 50% of the full customs value for entries since April 6, 2026, as our Section 232 note explains; assuming no reduced rate applies (the lower rates are for steel melted and poured in the US, which Taiwan wire rod rarely is), that's $20,000 whichever line you use. Underneath it, as bolts under 7318.15.20 the general duty is zero. As cap screws under 7318.15.80 it is 8.5%, or $3,400. That's before any other additional duties that apply to your entry, which your broker will add.

In the EU: head, material and 800 MPa

The EU's Combined Nomenclature splits the same heading on different questions. For screws and bolts with heads it asks about the head (slotted or cross-recessed, hexagon socket, hexagon, other), then whether the steel is stainless, and for non-stainless hexagon screws and bolts, the tensile strength. "Hexagon screws and bolts" is a single description; the bolt or screw question that decides the US duty doesn't come up.

Here's how the EU's 2025 imports from Taiwan fall across the main 7318 codes for screws and bolts, by Eurostat's figures:

CN codeGoods (Eurostat label, shortened)2025 imports from Taiwan, tonnes
7318 15 88Hexagon screws and bolts, non-stainless, tensile strength 800 MPa or more29,317
7318 15 82Hexagon screws and bolts, non-stainless, under 800 MPa1,610
7318 15 75Hexagon screws and bolts, stainless900
7318 15 68Hexagon socket head screws and bolts, non-stainless18,755
7318 15 58Slotted or cross-recessed head screws and bolts, non-stainless18,423
7318 15 95Screws and bolts with other heads32,900
7318 15 42 / 48Screws and bolts without heads, non-stainless, under / at least 800 MPa1,292 / 2,321

About 95% of the non-stainless hex screws and bolts the EU took from Taiwan in 2025 were declared at 800 MPa or more: 29,317 tonnes against 1,610. The same 800 MPa line also divides headless screws and bolts. Before choosing between 7318 15 82 and 88, your broker needs the tensile strength the parts are made to. If the supplier gives a property class instead, it should name the standard that defines it. The table shows eight-digit CN codes; the import declaration itself uses a ten-digit TARIC code, plus any additional codes the applicable measures require.

The CN code also feeds into trade defense. The EU's anti-dumping measure on certain Chinese steel fasteners is written against a list of CN codes, though it applies by origin, not by the code alone, as our EU duty note explains. For Taiwan-origin goods the code decides the regular duty and the statistics, and origin is the separate question covered in our certificate of origin note.

Put the deciding facts on the invoice

Back to the code on the Taiwan paperwork. 7318.15.90.00-7 is correct for Taiwan and tells your broker only that the goods are steel screws or bolts not for railway use. The facts that decide your line have to travel with the goods. CBP's guidance cites its invoicing rule (19 CFR 141.86(a)(3)), which asks for a detailed description of the merchandise, and says a fastener invoice should include:

For Taiwan hex fasteners going to both markets, add two things the general list doesn't spell out: whether the head has a washer face or chamfered underside (for the US), and the minimum tensile strength or property class (for the EU). A photo of the underside of the head documents the first; lot-linked inspection or test records support the second. If the line is in doubt, both systems let you ask in advance: a CBP ruling under 19 CFR Part 177, or a Binding Tariff Information decision in the EU.

So the HS code on a Taiwan invoice is a fair starting point for the first six digits and a poor guide to the rest. One hex bolt can carry three different codes, and in the US the line that decides between Free and 8.5% comes down to the underside of the head.

Need the deciding details from the factory?

We visit your Taiwan supplier, photograph the heads and markings of the parts in your order, collect the drawings and inspection certificates that state standard, grade and tensile strength, and send them to you in English for your customs broker.

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Classification depends on the actual goods; this note is a practical guide for buyers, not customs advice or a ruling. Duty rates and statistical lines change; check the current schedule with your licensed customs broker before you file.

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