HTS classification for metal parts

By Jessica Cui · Reviewed by Matthew Wu · Last updated 2026-10-13

Most importers meet hts classification for metal parts the first time a broker asks for a code. The broker is not being difficult. US Customs and Border Protection needs a classification before it can assess duty, and the code you declare becomes the basis of the entry. However, getting it wrong is expensive, because CBP can recover a duty shortfall later with penalties attached. The good news is that the logic is public, stable, and freely readable.

Classification starts with the material

First, steel parts usually begin in the chapter for articles of iron or steel. Aluminium parts begin in the chapter for aluminium articles. That sounds tidy, and it is a useful first filter. However, it is not the end of the analysis, and treating it as the end is the most common mistake we see.

However, the material only sets the starting point. Then the question becomes whether the part is a finished article in its own right or a part of something larger. If you are new to HTS classification for metal parts, start from the drawing rather than the invoice. The drawing tells you the material, the function and whether the part exists only to serve another machine.

Function can move a part out of its material chapter

For example, consider a stainless steel bracket that holds a sensor inside a machine. In isolation, it looks like a simple steel article. Once it is identified as a part of that machine, the classification can move to the chapter that covers the machine itself. Therefore the same drawing can produce two different codes depending on what the part is understood to be.

Therefore a classification note is worth writing down. It records the reasoning, the material, the function and the chapter you landed in. If CBP ever asks, you can show the analysis rather than reconstruct it from memory.

The General Rules of Interpretation are the method

The HTS is not a lookup table. It is a legal text, and it comes with a method for reading it. That method is the set of General Rules of Interpretation. In practice, the rules tell you to read the headings and the section notes before you look at anything else.

Therefore two consequences follow. First, section and chapter notes override the plain wording of a heading, so a note can exclude your part explicitly. Second, if two headings both seem to fit, the later rules decide which one wins, and that decision rests on essential character.

Where a face must be closer than the general rule allows, we work to ±0.05 mm on machined features. That tolerance discipline matters here for a practical reason. A classification argument that depends on a feature being present has to survive a measurement.

Where to get the official answer

However, you do not have to reason this out alone. Three official routes exist, and they are free.

The first is the Harmonized Tariff Schedule published by the US International Trade Commission. It contains the headings, the notes and the general rules. For the international nomenclature that sits underneath it, the World Customs Organization explains what the Harmonized System is.

The second is your local CBP port. As CBP advises new importers, an import specialist can discuss classification for your commodity and give an advisory duty rate. That conversation is free and worth having before the first shipment.

The third is a binding ruling. CBP issues written rulings on classification, and you can search what it has already decided for similar products.

Why we do not print a code for your part

A supplier can describe a part accurately and still not be the right party to fix its classification. The importer of record is legally responsible for the entry, including the code. Therefore we describe the material, the process and the function precisely, and we leave the code to you and your broker.

That is not evasion. A code printed in a marketing page would be a determination without the facts of your entry, and it would go stale as the schedule changes. What we can do is give you the inputs the analysis needs.

What we put on the drawing and the invoice

Classification runs on facts, so we try to make the facts explicit. For a typical stamped or deep drawn part, that means the alloy grade, the process route, the wall thickness, the surface finish and the function the part performs in the assembly.

In addition, we keep the documents consistent across shipments, so the invoice description, the packing list and the drawing agree with one another. A mismatch between documents invites questions that a clean file never receives.

If the parts are part of an assembly, tell us. The classification question changes the moment a bracket becomes a component rather than an article, and your broker will need to know which reading applies.

Frequently asked questions

These are the questions importers ask most often about classification.

Can my Chinese supplier tell me the HTS code?

We can describe the part and the material precisely, and we can explain how similar parts have been classified in our own shipments. However, the legal responsibility for the code sits with the importer of record, so the final decision should come from you, your broker, CBP directly, or a binding ruling.

Does the material alone decide the classification?

It sets the starting chapter, and then function and essential character can move the part elsewhere. A part that exists solely to serve a machine may leave the chapter its material would suggest. The section notes are the place to confirm this.

How do I know my code is still current?

Check the official schedule rather than any page you saved. The HTS is published and updated by the USITC, and it keeps a change record, so the current answer is always one click away from the source.

What if the classification turns out to be wrong later?

Voluntary correction is far cheaper than being found out. Speak to your broker about a prior disclosure if you discover an error. Importers who correct themselves are treated very differently from importers who are caught.