Section 232 steel and aluminum derivative duty, explained for importers

If you import anything made partly or wholly of steel, aluminum or copper, from a bracket to a kitchen appliance to a machine part, Section 232 probably affects your cost. The rules were rewritten in April 2026, and they changed in ways that matter more than the headline rate: the duty now generally applies to the whole customs value of a covered product, not just its metal content.

This guide explains the structure as CBP described it in its April 2026 guidance, shows what the change does to a real cost calculation, and lists the records you should keep. It is general information, not legal or customs advice. Section 232 lists and rates have been amended repeatedly, so confirm the current status of your exact tariff code with your customs broker and CBP's published guidance before you rely on any figure here.

What Section 232 is

Section 232 of the Trade Expansion Act of 1962 lets the President impose duties on imports found to threaten national security. Steel and aluminum duties began in 2018. Copper was added in 2025. Over 2025, the government also extended the duties to a growing list of derivative products, meaning goods made from those metals. These duties are additional to the ordinary HTS duty and to any Section 301 or antidumping duties.

The IEEPA tariffs are a different legal authority. The Supreme Court held those unlawful in February 2026. Section 232 was not affected by that ruling and remains in force.

What changed on April 6, 2026

A proclamation signed April 2, 2026 (published in the Federal Register April 9, 2026) restructured the metals measures effective April 6, 2026. CBP explained the operational details in CSMS message 68253075. The main points, as described by CBP and by law-firm analyses of the proclamation:

• Full customs value. Duty on covered steel, aluminum and copper articles and their derivatives now applies to the entire customs value of the imported product. Before this change, many derivative products were charged only on the value of the metal content, which required importers to split out that value.
• Tiered rates. Rates depend on which annex the product falls into. Articles in the highest tier are charged 50 percent. A second tier is charged 25 percent. Some UK-origin goods and some derivative goods have lower rates, for example 15 percent or 10 percent in specified cases.
• A metal-weight threshold. For articles outside HTS chapters 72, 73, 74 and 76, duties apply only where the applicable metal makes up at least 15 percent of the article's weight. Below that, the article can be reported under a zero-duty Chapter 99 line and the metal weight in kilograms is reported as a second quantity on the entry summary line.
• Products removed. The proclamation took a number of previously covered products, including many consumer goods, out of Section 232 coverage.
• Documentation of origin. Preferential rates for some partners depend on where the metal was melted and poured (steel) or smelted and cast (aluminum), so origin records matter.

Because these tiers and annex lists are long and were still being adjusted in the months after the proclamation, treat the table below as a map of the structure, not as a lookup for your part number.

Category (as CBP describes it)	Typical additional rate	Basis
Covered steel, aluminum and most copper articles; highest-tier derivatives	50%	Full customs value
Certain copper articles and second-tier derivatives	25%	Full customs value
Specified UK-origin goods	Lower rates in specified cases (for example 25% or 15%)	Depends on melt and pour or smelt and cast in the UK
Articles with less than 15% applicable metal by weight (outside chapters 72, 73, 74, 76)	0% under a dedicated line	Metal weight reported on the entry

What full-value duty does to your cost

Take a placeholder product with a customs value of $10,000 in a covered category with a 50 percent additional rate. Under full-value assessment, additional duty is 50 percent of $10,000, or $5,000, in addition to the ordinary HTS duty. Under the older content-based approach, if the steel made up, say, 40 percent of the value, the additional duty would have applied to $4,000 and cost $2,000. Same product, same rate, a very different cost, and this example is arithmetic only, not a claim about any specific product.

The reverse can also happen. A product that used to be caught because it contained enough metal may now be out of scope because it falls under the 15 percent weight threshold or was removed from the annexes. The lesson is that you should recalculate landed cost for every affected SKU instead of adjusting last year's number by a factor.

How to work out whether a specific product is covered

1. Get the ten-digit HTS code. Look it up at hts.usitc.gov and confirm with your broker. Section 232 treatment attaches to the code, not to the description on your invoice.
2. Check chapters 72, 73, 74 and 76 first. Articles classified in those chapters (iron and steel, articles of iron or steel, copper, aluminum) are the core of the measure, and the 15 percent weight threshold does not apply to them.
3. Look at CBP's guidance and the annexes. CSMS 68253075 lists the Chapter 99 numbers (in the 9903.82 range) for each treatment. Match your code against the annex that names it.
4. If your code is outside those chapters, find the metal weight. Ask your supplier for the weight of steel, aluminum and copper in one unit and the total unit weight. Anything at or above 15 percent may be caught; below it, it generally is not.
5. Confirm the country of origin and the metal's origin. Preferential or reduced rates for particular partners depend on where the metal was melted and poured or smelted and cast.
6. Record the result. Keep the code, the annex reference, the weight calculation and the supplier's documentation in the file for that SKU.

Records to keep

CBP can request substantiation years after an entry. For metals products, keep:

• Mill or smelter certificates showing where the metal was melted and poured or smelted and cast, where relevant to a preferential rate
• A bill of materials with metal weight per unit and total unit weight
• Your classification memo or your broker's classification confirmation
• The commercial invoice and packing list, with descriptions specific enough to support the tariff code (see the commercial invoice guide)
• Entry summary copies showing the Chapter 99 numbers actually declared

Mistakes that cost importers money

• Applying the old metal-content method. If your spreadsheet still discounts value to the metal share, it is out of date for entries after April 6, 2026.
• Assuming a product is exempt because it is "mostly plastic." The test in the affected categories is weight of applicable metal, and some parts are classified in metals chapters regardless of look.
• Not asking the supplier for weights. Suppliers often know unit weight and metal content and will provide it if you ask before ordering, not after the container ships.
• Forgetting stacking. Section 232, Section 301 and antidumping duties can apply to the same entry. Check CBP's guidance on which combinations apply to your goods.
• Ignoring the expiry dates on temporary provisions. CBP notes that some of the lower-rate lines expire on January 1, 2028, after which the goods convert to other lines. Put the date on your calendar if your product relies on one.

Sources

• CBP, CSMS # 68253075, Guidance: Section 232 Duties on Imports of Aluminum, Steel, and Copper (April 2026)
• Federal Register, "Strengthening Actions Taken To Adjust Imports of Aluminum, Steel, and Copper Into the United States," document 2026-06960, April 9, 2026
• BDO, "Section 232 Metals Tariffs Expanded and Recalibrated: What Importers Need to Know," for the summary of rate tiers and full-value assessment

Verified against CBP guidance and published summaries on September 21, 2026. Section 232 annexes and rates change; confirm the current entry for your tariff code before you rely on this guide.

Frequently asked questions

Does Section 232 apply to the full value of a steel or aluminum product?

Under the April 6, 2026 restructuring described in CBP guidance, Section 232 duties on covered aluminum, steel and copper articles and their derivatives generally apply to the entire customs value, not only to the metal content. Confirm treatment for your specific tariff code with your broker.

What is the 15 percent metal weight rule?

For articles outside HTS chapters 72, 73, 74 and 76, CBP guidance says the duty applies only where the applicable metal is at least 15 percent of the article's weight. Below that, the article can be entered under a zero-duty line with the metal weight reported as a second quantity on the entry line.

What are the Section 232 rates on steel and aluminum derivatives?

CBP and law-firm summaries describe a top tier of 50 percent and a second tier of 25 percent, with lower rates such as 15 percent or 10 percent in specified cases, such as certain UK-origin or U.S.-origin metal. Which tier applies depends on your tariff code and the annex that lists it, so check the current annex.

Did the Supreme Court IEEPA ruling end Section 232 tariffs?

No. The February 2026 Supreme Court decision concerned tariffs imposed under IEEPA. Section 232 tariffs rest on a different statute and remain in effect.