Section 232 Tariffs: Steel, Aluminum, and National Security Duties Explained

What Is Section 232?

Section 232 of the Trade Expansion Act of 1962 authorizes the President to restrict imports of any product when the Secretary of Commerce determines that the quantity or circumstances of importation threaten to impair national security. The statute is broader and more flexible than it sounds — it does not require an active military emergency or a specific adversarial trading partner. A finding that domestic production capacity in a strategically important industry has been eroded by import competition is sufficient.

Steel and aluminum qualified under this rationale because both are essential inputs for defense systems, shipbuilding, military vehicles, aircraft, and critical infrastructure. The Department of Commerce investigations, published in 2018, found that steel imports had grown to 30% of US consumption (from 18% a decade earlier) and that aluminum imports accounted for 90% of certain primary aluminum products, leaving US producers unable to sustain sufficient domestic capacity for national security requirements.

Critically, Section 232 differs from Section 301 in one key respect: it is not country-specific. The tariffs apply to imports from all countries, including longstanding US allies such as Canada, the European Union, Japan, South Korea, and the United Kingdom. Whether a country is a strategic partner or a geopolitical rival is, in the statute's framing, secondary to whether imports from that country are undermining the targeted domestic industry.

This made Section 232 politically controversial in a way that Section 301 was not. Allies objected strenuously to being classified alongside China as threats to US national security. The resulting exemption negotiations, partial suspensions, and tariff-rate quotas created a patchwork of country treatments that has evolved continuously since 2018 — and as of mid-2025, has largely reverted to a uniform global rate.

Current Section 232 Rates: Steel and Aluminum

The June 2025 doubling of steel and aluminum rates was the most significant Section 232 escalation since the program launched. The increase was justified by the administration on the grounds that foreign overcapacity — particularly from China, India, and Southeast Asia — had continued to grow despite the initial 2018 tariffs and that domestic production had not recovered sufficiently to meet defense requirements.

Copper was added to Section 232 coverage in March 2025 following a Department of Commerce investigation that found the US relied on imports for approximately 45% of refined copper consumption. Unlike steel and aluminum (which went to 50%), copper was set at 25% — reflecting a view that domestic copper capacity, while insufficient, is closer to recovery than steel or aluminum.

2026 Proclamation: Rate Structure by Annex

The April 2026 proclamation structured Section 232 duties across four annexes, each with different rate treatment. This replaces the prior flat-rate approach with a nuanced annex-based framework:

Source: Proclamation of April 2, 2026. Read the proclamation. Code counts are live from the HTS database.

Derivative Products: What Counts?

Section 232 covers not just raw steel and aluminum but also “derivative” products — finished goods where steel or aluminum is the primary input by value. This significantly expands the tariff's reach beyond Chapters 72 and 76 into manufactured goods across the HTS schedule. CBP applies a two-part test:

• The steel or aluminum content accounts for at least 50% of the article's total cost of materials (or a significant portion as determined by the applicable proclamation)
• The article would not be classified as a steel or aluminum mill product itself under the primary Section 232 proclamations

Examples of derivative products subject to Section 232 include:

If you import any fabricated metal products, the derivative product question is worth analyzing carefully. Search your HTS code to see whether Section 232 appears in your tariff record — check your code here.

Live Data: Section 232 Coverage Across the HTS Schedule

We query the HTS tariff database in real time to show current Section 232 designations. Here is the count of US tariff lines currently carrying a Section 232 surcharge, broken down by HTS chapter:

Chapters 72 (Iron and Steel) and 73 (Steel Articles) account for the majority of Section 232 codes, as expected. The distribution across chapters 74–90 reflects the derivative product rules, where manufactured goods with significant steel or aluminum content also carry the surcharge.

Affected HTS Chapters: Where to Look

The primary Section 232 exposure sits in three HTS chapters. If you import from any of these, you almost certainly pay Section 232:

Beyond these primary chapters, Section 232 derivative coverage extends into Chapters 82 (tools), 83 (miscellaneous metal articles), 84 (machinery), 85 (electrical equipment), 86 (railway), and 87 (vehicles), depending on the steel or aluminum content of specific products. Search your HTS code to get a definitive answer for your specific import.

Country Exemption History

Section 232 has had a complex history of country exemptions, tariff-rate quotas (TRQs), and renegotiated arrangements. Understanding this history matters because it affects cost modeling for different sourcing origins — and because current country frameworks can change again with future negotiations.

Canada is now the most significant affected partner. Before March 2025, Canadian steel and aluminum entered the US duty-free under the USMCA exemption. The revocation added a 50% surcharge overnight on Canada's ~$3B annual steel and aluminum exports to the US, triggering retaliatory tariffs on US goods.

How Section 232 Stacks with Other Duties

Section 232 stacks on top of all other applicable duties. The total cost depends heavily on the country of origin:

Use our landed cost calculator to compute the exact tariff stack for your specific product, origin, and shipment value. The country comparison tool shows side-by-side duty rates for the same HTS code across multiple origins.

Section 232 Timeline: 2017–2026

How to Check if Your Product Is Subject to Section 232

Search your HTS code in our tariff database. The result will show whether your code carries a Section 232 designation and what the current rate is. If you are importing fabricated metal products and are unsure whether derivative product rules apply, you can also browse the chapter-level tariff schedule to see which codes in your category have Section 232 flagged.

Start with the primary affected chapters:

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