Does machining a casting change its country of origin?

What test decides the origin of a cast-and-machined part?

For goods from most countries, including Vietnam and China, US Customs and Border Protection (CBP) applies the substantial transformation test: an article takes the origin of the last country where it became a new and different article of commerce with a new name, character or use.

CBP’s own summary of the rules, the informed compliance publication U.S. Rules of Origin, explains that the non-preferential schemes used for normal duty rates and for country of origin marking all rest on this name, character and use test, applied case by case. There is no single list of operations that pass or fail. CBP weighs the whole manufacturing history, and the rulings quoted below keep returning to one idea: whether the imported article already carried the “essence” of the finished part when it arrived.

Goods from Canada and Mexico are the exception. For marking, they follow the tariff-shift rules in 19 CFR Part 102, which ask whether each foreign material changed tariff classification rather than whether it changed name, character or use. Those rules do not apply to a part shipped from Vietnam, so the rest of this guide deals with the substantial transformation test.

When can work done after casting change the origin?

Mainly when the casting stops being the essence of the finished article: when it is combined with other components in a complex assembly, or when the later processing creates the function the product is bought for.

HQ 561297 itself shows the first case. The same castings, once machined into receivers and assembled with dozens of other components by trained technicians into a complete rifle, were held to be substantially transformed. The finished rifle was a new article, and the imported castings became materials inside it.

The second case appears in HQ 734835 (1993). Unfinished shear blade castings from Taiwan went through drilling, grinding, plating, edge sharpening, riveting and finishing in the US, and CBP found them substantially transformed into scissors. The sharpening and joining gave the product its cutting action, which the castings did not have when imported.

Neither case describes what most OEM buyers are doing. A housing or valve body cast close to shape and then faced, bored and tapped is still recognizably the same part. Each ruling applies only to the facts submitted, as 19 CFR 177.9(b)(1) states, so these older decisions show the reasoning rather than a rule you can rely on for your part.

Does casting imported ingot into a part create a new origin?

Generally yes. Ingot, scrap and alloying additives do not have the name, character or use of a finished part, and CBP has held that melting and casting them into a shaped part is a substantial transformation.

The most recent example is NY N364409 (2026). Chinese aluminum ingot, scrap and alloying metals were melted in South Korea, high-pressure cast in a dedicated die into an automotive steering knuckle, heat treated and machined. CBP found that the materials were substantially transformed when cast into the knuckle, which from that point had the basic shape and predetermined use of the finished part. The finished assembly was South Korean. The ruling also cites NY N301439 (2018), where foreign aluminum melted in South Korea into billets was likewise treated as a product of South Korea.

This is the mirror image of the casting-then-machining rulings. The step that fixes the part’s shape and use is the step that confers origin. Where the ingot was bought does not decide the origin of a part cast from it, though it can matter for other duties that follow the metal rather than the part. For an aluminum part die cast in Vietnam from imported ADC12 ingot, the same reasoning points to Vietnamese origin, subject to a ruling on the actual facts. The ADC12 and A380 guide covers the alloy side of that choice.

How can a buyer confirm the origin before moving tooling?

Request a binding country of origin ruling from CBP under 19 CFR Part 177, describing where the part is cast, where it is machined and finished, and what each step does. The ruling then applies to every entry that matches those facts.

A ruling request is only as good as its description of the process, so assemble the facts with the supplier before filing:

• Where the part takes its shape. The foundry or die caster, the country, and who owns and holds the die or pattern.
• A written routing. Every operation from ingot or blank to finished part, with the country where each one runs.
• Material records. Purchase documents for ingot, bar or blanks, with their origin.
• Drawings of each stage. The as-cast part next to the finished part, so the ruling officer can see how much of the shape existed before machining.

Published rulings can be searched at rulings.cbp.gov, and a close existing ruling is useful evidence even before you file your own. The same facts belong in the RFQ; the RFQ package guide lists what to send, and the quote form accepts the drawing and a note asking for the process routing and material source for each part number.