.svg)
.svg){kind=icon}
Before asking a supplier for a single document, a company importing steel into Mexico has to answer one question: which certificate does the tariff classification of what it buys require? The automatic import notice for steel products (AAIPS, for its Spanish acronym) is filed with Mexico's Ministry of Economy on the strength of one of two documents, the mill certificate (certificado de molino) or the quality certificate (certificado de calidad), and each one is issued by a different company in the steel chain. Requesting the wrong one, or receiving the right one with a missing data point, leads to a deficiency notice: Rule 1.4.5 of the Ministry's general rules and criteria on foreign trade (the Acuerdo de Reglas) gives the applicant five days to submit the information correctly, and if it does not arrive, the application is dismissed.
This guide brings together in one place what Rules 2.2.19 and 2.2.26 of the Acuerdo de Reglas establish for both certificates: who issues each one, which headings require which, the eight data points both must carry, the difference between the country of melt and pour and the country of origin of the goods, what counts as a signature, stamp or QR code, and the mill catalog in the VUTCE, Mexico's Single Window for Foreign Trade Procedures. For mills outside Mexico, one development from October 2026 matters on its own: in Boletín B.SNICE 003/2026, the Ministry clarified that a document titled Mill Test Report can support the notice when a full review shows it corresponds to the certificate type the tariff classification requires and meets the rule's content requirements.
Who issues each certificate: the mill that produced the steel or the manufacturer that transformed it
Section A of Rule 2.2.19 defines both documents by their issuer. The mill certificate is the document issued by the mill that identifies the company that produced the steel processed at that same mill. The quality certificate is the document that identifies the manufacturer that transformed the steel to make the goods being imported, and that manufacturer prepares it.
The word that settles the first definition is "mill", and the rule gives it a precise scope. A mill is a company that makes chapter 72 products of the Mexican tariff schedule through either of two processes. The first turns iron or scrap, melted in a blast furnace or an electric arc furnace, into semi-finished products such as slab, billet or ingot, in non-alloy, alloy or stainless grades. The second reheats those semi-finished products in reheating furnaces or hot-rolling mills to make flat products (hot-rolled, cold-rolled or silicon electrical steel) or long products (wire rod, bars, sections).
That second route has a practical consequence: a re-roller that buys billet and rolls it into bar also counts as a mill for purposes of the notice, even though it never melted the steel. The chain therefore holds three kinds of company: the melt shop that melts and casts, the rolling mill that reheats and rolls, and the manufacturer that turns the steel into a different product, such as welded pipe, drawn wire or a structure. The first two issue mill certificates. The third issues quality certificates.
Which heading requires each certificate
The tariff items subject to the AAIPS for permanent import are listed in Anexo 2.2.1, section 8, subsection II, of the Acuerdo de Reglas, and they span chapters 72 and 73 of the tariff schedule. The Ministry of Economy assigns those items to one certificate or the other by four-digit heading, as set out in its quick guide for filing AAIPS applications and its guide for enrolling in the steel importer registry, both published on SNICE, the Ministry's foreign trade information portal.
CertificateHeadingsWhat they coverMill certificate7206 to 7216, 7218 to 7228 and 7304Ingots, semi-finished products, flat-rolled products, wire rod, bars and sections of non-alloy, stainless and alloy steel, plus seamless tubes and pipesQuality certificate7202, 7217, 7229, 7301, 7302 and 7305 to 7317Ferroalloys, wire, sheet piling, railway track material and chapter 73 articles such as welded pipe, tube fittings, structures, stranded wire and cables, chains and nails
Two groups of headings cross chapters. Heading 7304, seamless tubes and pipes, sits in chapter 73 and requires a mill certificate. Headings 7217 and 7229, wire, sit in chapter 72 and require a quality certificate. That is why the question is answered by the first four digits of the Mexican tariff code, and the code itself by a correct tariff classification. The certificate is also one of three controls that land on every steel shipment into Mexico, together with the sector-specific importer registry and the notice itself.
Quick check. Take last quarter's steel pedimentos (Mexico's customs declarations) and group the tariff codes by their first four digits. For each heading, confirm in the table which certificate applies and compare it with the one your supplier sends today. If a quality-certificate heading arrives with a mill certificate, or the other way around, that supplier needs different purchasing instructions before the next shipment.
The eight data points both certificates must carry
Section B of Rule 2.2.19 sets the content. Both certificates share the list, and three of the data points change with the type:
The three data points that separate the documents are the heat, the country and the issuer. The heat number identifies the batch of molten steel the material came from, and the mill that produced it assigns it. The quality certificate documents a later process: the manufacturer that took that steel and turned it into the goods you import.
Subsection IX of the same section adds a ninth requirement that travels with the certificates and is signed by the importer: the carta responsiva, a statement in which the importer's legal representative declares that the certificates are on file, unaltered, scanned from their originals and available to the authority on request.
Three formal details are best settled with the supplier at the time of purchase. The Ministry's quick guide asks for a free Spanish translation of the mill certificate, which applies to every mill that issues in English. Its importer registry guide asks for the conversion method to be attached when the certificate states weight in a unit other than kilograms, for example when a US mill reports weight in pounds. And the description, volume and unit price entered on the application have to be readable on both the certificate and the commercial invoice, because Rule 2.2.15 requires the value and unit price on the notice to match the invoice covering the import.
→ If your steel purchasing catalog mixes mill-certificate and quality-certificate headings, talk to a Joffroy expert to review which certificate to request from each supplier before the next purchase order.
Country of melt and pour, or country of origin of the goods
Under Section A of Rule 2.2.26, the notice application asks for two different countries, and each one must match a certificate. The country of origin of the steel is the country where it was produced, melted and poured, and it must match the one declared on the mill certificate. The country of origin of the goods is the country where the manufacturer transformed the steel to make the goods, and it must match the one declared on the quality certificate.
The same rule defines melting and pouring: the original location where the raw steel was first produced in a steelmaking furnace in liquid form and then poured into its first solid shape, which can be a semi-finished product (slab, billet or ingot) or a finished mill product. The requirement excludes the process's raw materials: steel scrap, iron ore, pig iron, reduced, processed or pelletized iron ore, and raw alloys. Companies that also ship steel into the United States will recognize the concept from the melt-and-pour reporting CBP requires on steel entries.
The distinction matters when steel crosses more than one border before reaching Mexico. Picture a bar rolled in one country from billet melted and poured in another. The re-roller is a mill under the Rule 2.2.19 definition, and even so, the country that goes on the application as the steel's country of origin is the one where it was melted and poured. Rule 2.2.26 anticipates where that data comes from: mill certificates are generated at each stage of the production process, and that is usually where the melt and pour location is identified. For welded pipe, the country of origin of the goods is the country of the manufacturer that formed and welded the pipe, regardless of where the sheet was rolled.
Beyond the two countries, the application asks for the country of export to Mexico, the name and address of the goods' manufacturer and the name of the mill. That is why, even for tariff items that require a quality certificate, it pays to ask the manufacturer at the purchase order stage to identify the mill that produced the steel it transformed.
Handwritten signature, stamp or QR code: what the rule accepts as the issuer's mark
Subsection VIII of Section B accepts three ways to authenticate the certificate, and the February 2026 amendment defined each one in Section A. A handwritten signature is one a person traces by hand on the document; a signature added digitally falls outside that definition. The stamp is the one the issuer applies directly to the document; a stamp added digitally is not considered valid. The QR code holds information linked to the certificate, allows its authenticity to be verified and must lead to the original certificate.
The three definitions share one logic: the mark comes from the issuer and can be traced back to the original document. Rule 1.4.4 of the Acuerdo de Reglas completes it on the importer's side. The digital copy submitted through the single window is made from the original or from a certified copy, and the authority can request those originals at any time for comparison.
In the steel imports we clear at 39+ ports, the certificate is reviewed as one more document of the pedimento, alongside the invoice and the packing list. Before the application goes in, we check three things: that the description and kilograms on the certificate match those on the invoice, that the issuer matches the mill or manufacturer to be declared, and that the authentication mark is one of the three the rule defines. When one of the three does not line up, the correction is requested from the supplier before the application is filed, while there is still room in the shipment's schedule.
The mill catalog in the single window
The application's last data point has its own mechanics. Subsection X of Section A of Rule 2.2.26 requires the mill's name to be selected from the catalog the single window displays. The catalog published on SNICE shows each mill's identification number; the version available on the SNICE steel microsite is current as of July 16, 2026.
If the mill is missing, the rule provides for its enrollment through an escrito libre (a free-form written request) under Rule 1.3.5, sent to inscripcion.molinos@economia.gob.mx with three attachments: the Excel form published on SNICE, fully completed; the applicant's current positive tax compliance opinion issued by the SAT (Mexico's tax authority); and a mill certificate that meets Rule 2.2.19, issued no more than six months earlier. The authority verifies that the mill exists and, where appropriate, adds it to the catalog within ten business days, and the Ministry's Directorate General for Trade Facilitation and Foreign Trade (DGFCCE) may request additional information under Rule 1.3.9.
For purchasing teams, those time frames become a calendar rule. A new supplier whose mill is missing from the catalog needs at least two weeks of lead time before the notice application can be entered, plus the time to gather a recent certificate. Importers with frequent operations can also opt for the Registro de Importadores de Productos Siderúrgicos, the annual steel importer registry under Section B of the same rule, which authorizes notices valid for one year and requires mill or quality certificates to be available to the authority on request.
Two documents decided at the purchase order
The mill certificate and the quality certificate answer the same need of the Ministry of Economy: knowing who produced the steel, where it was melted and poured, and who transformed it. The heading decides which of the two is filed, Rule 2.2.19 decides what it must contain, and Rule 2.2.26 decides how its data is cross-checked against the application. All three answers are known before buying, which makes the purchase order the moment to request the right certificate, while the supplier still has the lot, the heat and the original document at hand.
Does your steel purchase order tell your supplier today which certificate to send, and with which data?
. . .
Talk to a Joffroy expert to map the headings in your steel catalog against the certificate each one requires and write that instruction into your purchase orders.
TRADE. UNDER CONTROL.
