Section 232 Now Taxes the Whole Machine Base, Not Just the Steel

Since April 2026, US Section 232 duty on steel derivatives is charged on full customs value. What that means for the landed cost of a machine base from Vietnam.

In April 2026 the United States changed how Section 232 duty on steel, aluminium and copper derivatives is calculated. It used to be charged on the value of the metal inside the product. It is now charged on the product’s full customs value. For a US machine builder importing a welded steel or cast-iron machine base, that change moves the machining, the stress relief and the inspection into the dutiable base as well as the plate.

This guide covers what changed, how it interacts with the separate tariff on Vietnamese goods, and how to quote and compare so the landed cost does not surprise you. It is not customs advice. The HTS classification and the duty rate that applies to your part are decisions for your licensed customs broker. The duty layer is the last step of the machine base supplier path, after classification and origin.

What changed, and when

A presidential proclamation signed on 2 April 2026 took effect for goods entered on or after 12:01 a.m. ET on 6 April 2026. CBP’s implementing guidance, CSMS # 68253075, describes the duties as imposed on the full customs value of covered metal articles and their derivatives.

The proclamation sorted covered goods into annexes with different rates. As summarised by GHY and by law firms including BDO and Phillips Lytle:

• Annex I-A, 50%. Articles made entirely or almost entirely of steel, aluminium or copper, plus certain listed derivatives.
• Annex I-B, 25%. Derivative articles substantially made of those metals.
• Annex III, 15%. Metal-intensive industrial and electrical grid equipment. The duty is set so that the combined rate with normal duty comes to 15%, and this reduced treatment runs to 31 December 2027.
• Below 15% metal by weight. Goods whose covered metal is less than 15% of the article’s weight are not subject to the Section 232 duty.

A second proclamation on 1 June 2026, effective 8 June 2026, widened the reduced-rate treatment to further categories including agricultural equipment, residential HVAC and certain mobile industrial machinery, again through 31 December 2027. It also relaxed the threshold for “US metal” content from 95% to 85%. Where a product contains more than one covered metal, only one Section 232 duty applies, at the highest applicable rate.

Two reporting points matter to anyone sourcing steel: importers must continue to report the country of melt and pour for steel and steel derivatives, and CBP guidance says antidumping, countervailing and other duties continue to apply alongside Section 232.

Where a machine base might fall

This is the question buyers want answered, and it is the one we will not guess.

A welded base, frame or column shipped on its own could plausibly be entered as an article of iron or steel, as a structure, or as a part of a machine tool, depending on how it is made, how far it is finished and what it is dedicated to. Each of those headings may or may not appear in an annex, and at different rates. A cast-iron bed raises its own classification question. A base with polymer concrete or grout fill may change the metal-by-weight calculation.

None of the sources we checked lists machine bases by name. So the practical rule is simple: get the HTS line and the annex confirmed by your broker, in writing, before you sign the purchase order. Give them the drawing, the material list with weights, the level of machining and the machine the base goes into.

The Vietnam tariff, and why it may not stack

Separately, on 24 July 2026 the US began charging a 12.5% Section 301 tariff on most imports from Vietnam, following USTR’s forced-labour investigations. It replaced a temporary 10% surcharge under Section 122 that expired the same day. Global Trade Alert’s review of the final action reports that goods covered by the enumerated Section 232 programmes are exempted from that 12.5%.

For a steel machine base that means two quite different outcomes, depending on classification:

If the base as imported is…	Likely additional duty to model
Covered by a Section 232 annex	The Section 232 rate for that annex, on full customs value
Not covered by Section 232	The 12.5% Section 301 rate, unless another exemption applies

In both cases normal column 1 duty applies as well. Your broker confirms which row you are in.

The picture may move again. On 22 September 2026 VnExpress International reported that USTR Ambassador Jamieson Greer told Vietnam’s leadership the two negotiating teams were very close to a final outcome on a reciprocal trade agreement. Until something is signed and published, model the rates in force today, and put a review date in your cost sheet.

What full-value duty does to a quote

Under the old method, the heavy machining on a base sat outside the Section 232 calculation. A base where plate was a modest share of the price paid duty on a modest share of the price. Now everything the fabricator does before the crate is closed is dutiable if the base is covered: cutting, welding, stress relief, machining, inspection, painting.

Three consequences for how you compare quotes:

1. Compare landed cost, not ex-works price. A Vietnamese base that is cheaper ex-works can land at a different ranking once duty is applied to its full value. Build the landed-cost sheet per supplier country, not one sheet with a single duty line.
2. Machining value no longer escapes duty. If you were planning to import a rough weldment and machine it in the US to save money, that is an engineering and capacity decision now, not a tariff loophole. It changes what is imported and may change its classification, so run it past your broker too.
3. The Incoterm changes the arithmetic, not the base. US customs value is generally built on the transaction value of the goods, which normally leaves out international freight and insurance. Quote on a clear Incoterm with the freight shown separately so your broker can see exactly what the goods are worth. See what a machine base costs for how the price itself is built up.

What to ask the supplier

Put these in the RFQ so they come back with the quote rather than after the order:

• Country of melt and pour for every steel plate and section, with the mill certificates that show it. Importers must report it, and a fabricator buying plate from mixed sources needs to know which heats went into your part.
• Material weights by type, including any non-metal fill, so your broker can apply the 15%-by-weight test where relevant.
• An honest cost breakdown of material, fabrication, stress relief, machining, inspection and packing, for your own comparison. Not a split invoice: the customs value is the value of the whole article.
• A goods description and HS suggestion from the exporter’s side, clearly labelled as a suggestion. It helps your broker, and it shows you whether the supplier has shipped this kind of part before. The document pack itself is covered in export documents for machinery from Vietnam.
• Ship date and transit time, so you know which rates will be in force when the goods are entered. Duty is set by the entry date, not the order date.

Timing

Three dates are worth writing into a sourcing plan:

• 31 December 2027, when the reduced Annex III treatment is scheduled to end.
• The date any US-Vietnam agreement is signed and published, which could change the country-level tariff.
• Your own entry date. A multi-tonne base with a long build and a sea leg can be ordered under one set of rates and cleared under another. Leave margin in the budget for that.

Buyers outside the United States

Section 232 is a US import measure. A machine builder in Germany, Japan or Korea clearing a Vietnamese base into its own market is not affected by it, although its own market’s duties and origin rules still apply.

Checklist before you order

1. Broker confirms the HTS line and whether it sits in a Section 232 annex, and at what rate.
2. Broker confirms whether the Section 301 12.5% or Section 232 applies, and the normal column 1 duty.
3. Supplier provides melt-and-pour country and mill certificates for all steel.
4. Supplier provides material weights, including any fill.
5. Quotes compared on landed cost per supplier country, not ex-works.
6. Incoterm stated, freight shown separately.
7. Review date set in the cost sheet for any change in the Vietnam tariff.

Getting a quote you can cost properly

If you are pricing a base or frame from Vietnam and need the supplier-side information above to come back with the price, send the drawing through the RFQ form. We are a sourcing service, not a fabrication shop: we match your drawing to Vietnamese fabricators that build structures of that size and class, and ask them for melt-and-pour country, material weights and a cost breakdown alongside the quote. You will hear back within 24 business hours.

Common questions

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