Guide
What is the HTS code for machined aluminum parts?
An HTS code is the ten-digit number from the Harmonized Tariff Schedule of the United States that tells customs what an imported product is, which duty rate applies and which statistics it is counted under. For a machined or die-cast aluminum part there is no single answer: a large share end up in the catch-all subheading for other articles of aluminum, but many belong with the machine, pump or fixture they are made for, and the rules decide which, not the material alone.
By Saola Manufacturing engineering team · Published · Updated
This guide walks through the reasoning customs uses, shows two rulings on machined aluminum parts that went opposite ways, and explains how to get a binding answer before the first shipment. It is general guidance, not a classification of your part; the importer of record and its customs broker own the final code.
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Which HTS code do most machined aluminum parts fall under?
When no more specific heading describes the part, a machined aluminum part falls in subheading 7616.99.51, “other articles of aluminum: other: other,” which carries a general duty rate of 2.5 percent in the current schedule (USITC, HTSUS 7616.99.51). The last two digits are a statistical suffix: 7616.99.5160 for castings and 7616.99.5190 for most other machined articles.
Heading 7616 is a residual or basket provision. In a 2025 ruling on a machined aluminum coolant nozzle, CBP quoted the international Explanatory Notes to describe the heading as covering aluminum articles made by forging, punching, cutting, stamping, turning, milling or perforating, other than those covered more specifically elsewhere in the tariff (CBP ruling NY N346571). That last clause is the whole story: 7616.99.51 is where a part lands after every more specific heading is ruled out.
The suffix does not change the duty rate, but it must be correct on the entry because it drives trade statistics and, at times, which additional measures apply. Whether a heavily machined casting is still reported as a casting is worth asking your broker explicitly.
How do the General Rules of Interpretation decide the code?
Classification starts with GRI 1: the terms of the headings and any section or chapter notes decide the heading, and the later rules apply only when those do not settle it. Section and chapter notes are law, so a note that excludes a product overrides a heading that seems to describe it.
The General Rules of Interpretation sit at the front of the schedule and are part of the statute (USITC, General Rules of Interpretation, HTSUS 2026). For aluminum parts, three of them do most of the work:
- GRI 1. Read the headings and the legal notes first.
- GRI 2(a). A heading that names an article also covers it unfinished, as long as the unfinished item already has the essential character of the finished one. A rough casting or a semi-machined blank that can only become one specific part is usually classified as that part.
- GRI 3. When two headings both seem to apply, the more specific description wins; ties go to essential character, then to the heading that comes last in numerical order.
The US schedule adds its own rules of interpretation. The one that matters most here is Additional US Rule 1(c): a provision for “parts” covers products used solely or principally as parts of an article, but a parts provision does not prevail over a specific provision for that part or accessory. In plain terms, a part is first classified by what it is (a screw, a valve body, a bracket) and only then by what it goes into.
When is an aluminum part classified as a machine part instead of an article of aluminum?
When it is suitable for use solely or principally with one kind of machine and is integral to how that machine works, it is classified with the machine under Section XVI, not in Chapter 76. Note 1(f) to Section XV excludes articles of Section XVI from the base-metal chapters, so a qualifying part never reaches 7616.
Note 2 to Section XVI then sets the order of play (USITC, Section XVI notes, HTSUS 2026). A part that is itself a good named in a Chapter 84 or 85 heading, such as a valve, a bearing or a pump, goes to that heading. Any other part suitable solely or principally for one kind of machine goes with that machine or to its dedicated parts heading, for example 8413.91 for pump parts or 8466 for parts of machine tools. Everything else goes to the general heading 8487 for machinery parts without electrical connectors, or 8548 for electrical ones.
Two CBP rulings from 2025 show how thin the line is. In the first, a builder of CNC machining centers asked for its machined aluminum coolant nozzle to be classified as a machine-tool part in heading 8466. CBP refused: the nozzle used a common pipe thread, fitted many machines and ordinary fittings, and had no specialized feature that the coolant system could not do without, so it went to 7616.99.5190 (NY N346571). CBP applied the court tests for a “part”: integral to the article’s function, and dedicated to it rather than a separate commercial item.
In the second, finished heatsinks machined from aluminum extrusions for a line of plasma cutting machines were classified in 8466.93.9885 as machine-tool parts (NY N347079). The request showed fins engineered per machine model, pockets and tapped holes matched to that model’s electronics, and a fit to one machine only. Same material, similar machining, different heading: the difference was evidence of dedication and function.
Which other HTS headings commonly apply to aluminum parts?
Fasteners, profiles, tubes, structures, fixtures and parts of specific machines or vehicles all have their own headings, and each of these beats 7616 when it describes the part. The table lists the headings buyers of machined and cast aluminum most often meet, with the general rate published for each.
| What the part is | Where it usually goes | General rate | Why |
|---|---|---|---|
| Machined aluminum article not named anywhere else | 7616.99.5190 | 2.5% | Residual heading for other articles of aluminum (NY N346571) |
| Aluminum casting not named anywhere else | 7616.99.5160 | 2.5% | Same subheading, casting statistical suffix |
| Aluminum screws, bolts, nuts and similar threaded fasteners | 7616.10.70 or 7616.10.90 | 5.5% or 6% | Split at shank, thread or hole diameter of 6 mm |
| Bar, rod or profile still in that form | Heading 7604 | 1.5% to 5% | Specific heading for semi-finished shapes |
| Aluminum tube or pipe of alloy | 7608.20.00 | 5.7% | Specific heading for tubes and pipes |
| Bracket or similar fixture that hangs or supports a load | 8302.50.00 | Free | Base-metal brackets and fixtures (NY N361563) |
| Part dedicated to a pump | 8413.91.90 | Free | Section XVI note 2(b), parts of pumps |
| Part dedicated to a metal-cutting machine tool | 8466.93 | 4.7% (most lines) | Section XVI note 2(b), parts of machine tools (NY N347079) |
| Machinery part with no specific parts heading, no electrical connectors | 8487.90.00 | 3.9% | Section XVI note 2(c), fallback for machinery parts |
Two traps are worth calling out. First, “parts of general use” such as screws, bolts, springs and base-metal fittings, defined in Note 2 to Section XV, are kept out of the machinery chapters by Note 1(g) to Section XVI, even when sold as spares for one machine. Second, Note 1(g) and Note 1(h) to Section XV carve Section XVII (vehicles, aircraft, vessels) and Section XVIII (instruments, Chapter 90) out of the base-metal chapters, so a dedicated aluminum part of a car or a gauge usually belongs with that article. The exception runs the other way for general-use items: Note 2 to Section XVII keeps parts of general use out of the vehicle chapters, so an aluminum fitting of that kind sold for a vehicle stays in Chapter 76.
The 2026 ladder-bracket ruling shows the fixture trap in action. The importer proposed a mountings heading for all three items; CBP turned that down on two grounds, that the items attach and detach rather than stay fixed, and that ladders are not the kind of article heading 8302 has in view. It then put the ladder-jack bracket in 8302.50 and both ladder stabilizers, models AC96 and AC78, in 7616.99.5190 (NY N361563).
Does a die-cast or unfinished aluminum part get a different HTS code?
Usually not a different heading: under GRI 2(a), a rough casting or partly machined blank that already has the essential character of the finished part is classified as that finished part. What can change is the statistical suffix, and a generic casting that could still become many parts may stay in 7616.
The practical questions are how far the part is from finished and whether its shape already commits it to one use. A pump volute cast to final shape, with only bores and faces left to machine, generally has the essential character of a pump part; a plain cast billet does not. If castings are machined after import, describe both conditions in any ruling request, because customs classifies goods as entered.
Alloy does not move the heading. Chapter 76 applies to aluminum alloys generally, whether the part is a die-casting alloy or a wrought grade; the ADC12 and A380 alloy guide covers how those alloys are specified on drawings. Aluminum content can matter for additional duties, so keep alloy certificates and weights with the shipping documents. For a sense of which parts are cast and which are cut from bar, see the die casting and CNC milling pages.
How do you get a binding HTS classification from CBP?
Ask for an advance ruling under 19 CFR Part 177, most easily through the CBP eRulings portal, before the goods are imported. The ruling binds CBP for the requester on the facts described, so the quality of the description decides the value of the answer.
The regulations in 19 CFR Part 177 let an importer, exporter or their agent ask for a ruling on a prospective transaction. CBP’s eRulings guidance says its National Commodity Specialist Division generally issues classification rulings in 30 calendar days from receipt, longer when a lab report or another agency is involved (CBP, eRuling requirements). Every ruling closes by stating that it applies only to the facts provided, citing 19 CFR 177.9(b)(1), so a request that leaves out the machine or the function invites a basket-heading answer.
A strong request for an aluminum part includes:
- The drawing and a photo or model image, with the alloy and the process (cast, machined from bar, machined from extrusion).
- What the part does, what it is installed in, and the heading of that machine or article.
- Whether it fits only that machine or model, and the features that make it dedicated, as in the heatsink ruling above.
- The condition as imported, from rough to finished and coated.
- Your proposed classification with the GRI and note reasoning.
Before filing, search the Customs Rulings Online Search System at rulings.cbp.gov for parts like yours. Other companies’ rulings do not bind your entries, but they show how CBP reasons. The same drawing package belongs in your RFQ, which the RFQ preparation guide lays out.
What additional duties apply on top of the HTS rate for aluminum parts?
The column 1 rate is only the base; Chapter 99 of the schedule adds measures that depend on the code, the country of origin and sometimes the aluminum content. These change often, so check them on the date of entry rather than relying on any published summary, including this one.
For aluminum, the main overlay is Section 232. Since 2025, subheading 7616.99.51 and many other aluminum derivative codes have been reported with a Chapter 99 heading for Section 232 aluminum duties, as the coolant-nozzle ruling set out (NY N346571). The structure has since been revised; in the 2026 schedule, derivative aluminum articles are listed under US note 16 to subchapter III of Chapter 99, with separate lines by product group (USITC, HTSUS Chapter 99, 2026). In the Revision 19 text, note 16(c) names 7616.99.5160 and 7616.99.5170 as articles of aluminum and 7616.99.5190 as a derivative aluminum article, so do not assume a machined aluminum part sits outside Section 232 just because it is a finished component. Coverage, and whether duty applies to full value or aluminum content, is a line-by-line question for your broker.
Country-specific measures sit on top. The reciprocal tariffs imposed in 2025 under the International Emergency Economic Powers Act were ended by an executive order in February 2026 (Executive Order 14389), which also refers to other measures issued the same day. One of those, a temporary import surcharge under Section 122 of the Trade Act of 1974 (Federal Register, February 25, 2026), was limited by statute to 150 days and lapsed in July 2026. What replaced it for many origins, Vietnam among the 60 economies investigated, is a set of Section 301 duties at 10 or 12.5 percent depending on the economy; the notice sets 12.5 percent for products of Vietnam, with exemptions listed in its annexes (USTR notice, Federal Register, July 28, 2026). Check the tier and exemptions that apply to your origin and code on the entry date. The 2025 order that set rates by country also created a separate penalty duty for goods found to be transshipped to evade duties (Executive Order 14326, section 3). This guide cannot confirm how that transshipment provision stands today; read both documents and the current CBP guidance with your broker.
For parts made in Vietnam, origin, not the HTS code, changes the overlay. A part genuinely cast or machined there carries Vietnamese origin; one only repackaged there does not. Ask any supplier where the casting was poured and the machining done, and keep that record with the entry. The tariffs and origin page covers country-of-origin questions in more detail; treat its part-family summaries as a starting point and confirm Section 232 coverage against note 16 for your exact 10-digit line.
Frequently asked
Is an HS code the same as an HTS code?
The first six digits are the international Harmonized System maintained by the World Customs Organization and are shared by every member country. The US adds digits for its own tariff lines and statistics, so the full ten-digit HTS code only applies to US imports, and the supplier’s export code may differ after the sixth digit.
Who is responsible for choosing the HTS code?
The importer of record. US law requires the importer to use reasonable care when declaring classification and value (19 U.S.C. 1484). A supplier or forwarder can suggest a code, but the legal responsibility stays with the importer.
Does anodizing or plating change the HTS code of an aluminum part?
A surface finish does not normally change the heading, because the part is still an article of aluminum or still the same machine part. Report the finished condition in any ruling request anyway. The finishing guide and the surface finishing page describe the common options.
Does the country of origin change the HTS code?
No. The code describes the goods and is the same whatever the origin. Origin changes the rate column that applies, the Chapter 99 measures and the marking rules.
Can I rely on a ruling that CBP issued to another company?
Not as a binding answer for your own entries, since each ruling applies to its requester and facts. It is still strong guidance, and citing a close ruling in your own request or in discussions with your broker is common practice.
Sources
- General Rules of Interpretation and Additional U.S. Rules of Interpretation, Harmonized Tariff Schedule of the United States, Revision 19, USITC, 2026
- Chapter 76, Aluminum and articles thereof, HTSUS Revision 19, USITC, 2026
- Section XV notes (base metals), printed with Chapter 72, HTSUS Revision 19, USITC, 2026
- Section XVI notes and Chapter 84, HTSUS Revision 19, USITC, 2026
- Chapter 99, temporary legislation and modifications, HTSUS Revision 19, USITC, 2026
- HTSUS search, subheading 7616.99.51, USITC, accessed September 2026
- NY N346571, tariff classification of a coolant nozzle, U.S. Customs and Border Protection, March 26, 2025
- NY N347079, tariff classification of finished aluminum heatsinks for plasma arc cutting machines, U.S. Customs and Border Protection, April 16, 2025
- NY N361563, tariff classification of an aluminum bracket and ladder stabilizers, U.S. Customs and Border Protection, June 11, 2026
- 19 CFR Part 177, Administrative rulings, eCFR, accessed September 2026
- eRuling requirements, U.S. Customs and Border Protection, accessed September 2026
- 19 U.S.C. 1484, Entry of merchandise, via Cornell LII, accessed September 2026
- Executive Order 14326, Further Modifying the Reciprocal Tariff Rates, Federal Register, August 6, 2025
- Executive Order 14389, Ending Certain Tariff Actions, Federal Register, February 25, 2026
- Proclamation, Imposing a Temporary Import Surcharge (Section 122), Federal Register, February 25, 2026
- USTR, Notice of Actions in Section 301 Investigations of Various Economies (forced labor), Federal Register, July 28, 2026
- HS Nomenclature 2022 edition, World Customs Organization, 2022