How to Read a Mill Test Certificate (MTC) for Steel Coil

A mill test certificate (MTC) is the mill’s written statement of what a specific coil actually is — its cast chemistry, its tensile results, its coating mass. The only parts you can rely on commercially are the parts a standard forces the mill to stand behind.

Read it in this order: the EN 10204 document type, the heat or cast number and its link to the coil tag, the grade and its chemistry limits, the mechanical results, and the coating mass notation. Those five fields are where certificate disputes usually start, and each one is checkable at document stage.

Timing matters more than most buyers expect. Under an LC you pay against documents. Once the container is at Karachi and you can finally see the steel, a certificate problem is a claim, not a rejection — so the leverage sits before you accept the draft, not after.

Scope, editions and the decimal comma

This guide covers cold rolled coil, galvanized (GI/GP) and galvalume. Hot rolled coil is a different set of standards and is not covered here; see our separate note on cold rolled versus hot rolled coil for where the two part company.

Three things to fix before you start reading numbers.

• Editions are load-bearing. The EN 10346 clause and table numbers used below are those of the EN 10346:2009 text. EN 10346:2015 is the current edition and it differs — it adds a zinc-aluminium-magnesium (ZM) coating family and changes some footnotes. Check which edition your order and your certificate name.
• Grade name, not material number. Material numbers for the DX grades changed between the withdrawn EN 10142 and EN 10346, and published sources still disagree about them. Write the grade designation and the standard with its year on the purchase order — DX52D+Z to EN 10346:2015 — and never order against a material number alone.
• EN standards print a decimal comma. On a European certificate, 0,045 means 0.045. This guide uses the decimal point throughout, so figures can be transcribed straight into a purchase order without a units argument.

Step 1: EN 10204 types 2.1, 2.2, 3.1 and 3.2 — which certificate do you have?

EN 10204:2004 defines exactly four inspection document types. The type tells you whether the numbers on the page were measured on your material or on something else.

The standard splits inspection into two bases. Non-specific inspection is, in EN 10204’s own words, “inspection carried out by the manufacturer in accordance with his own procedures… The products inspected are not necessarily the products actually supplied.” Specific inspection is “inspection carried out, before delivery, according to the product specification, on the products to be supplied or on test units of which the products supplied are part.”

That distinction is the whole game. A 2.2 carries real laboratory numbers, but the mill is not obliged to have measured them on your coil, and you have no way to compel proof that it did.

Four practical points follow.

• Old codes mean an old edition. If a certificate presented to you today says 3.1B, it is quoting the withdrawn 1991 edition. Type 3.1 replaced 3.1.B; type 3.2 replaced 3.1.A, 3.1.C and the old inspection report 3.2. Type 2.3 was deleted altogether.
• Even a 3.1 can carry over results. EN 10204 permits the manufacturer “to transfer on to the inspection certificate 3.1 relevant test results obtained by specific inspection on primary or incoming products he uses, provided that the manufacturer operates traceability procedures and can provide the corresponding inspection documents required.” A galvanizer can legitimately quote the chemistry of the incoming full-hard substrate — and that closing condition is your lever to demand the substrate certificate.
• A 3.2 needs your action before rolling starts. EN 10346 clause 8.1.3 requires that the purchaser “shall notify the manufacturer of the name and address of the organization or person who is to carry out the inspection.” Asking for a 3.2 after shipment is not possible.
• Nothing is owed unless you ordered it. EN 10346 clause 8.1.1 states that “unless otherwise specified at the time of enquiry and order… the products shall be delivered with non-specific inspection without inspection document.” No certificate is due unless you asked for one on the order, so put the EN 10204 document type in the purchase order and in the LC — not in an email after shipment. Our explainer on how LCs work for steel imports covers where this sits in the documentation chain.

Stamps, signatures and validation

EN 10204 clause 5 requires only that “the inspection document shall be validated by the responsible person(s) (name and position),” and that retention and transmission “shall be either in electronic data or paper form.” EN 10204 itself imposes no wet-signature, embossing or rubber-stamp requirement, although EN 10168 does provide a field for one (Z 03, stamp of the inspection representative). A missing stamp is therefore a formatting gap and a commercial question worth asking, not in itself a breach of EN 10204. A missing named validator is a different matter — that one the standard does require.

Step 2: Trace the heat number — and what the coil tag does not carry

Most coil landing at Karachi comes from Chinese, Japanese, Korean, Indian, Turkish or Gulf mills, and their certificates are free-form tables rather than coded European forms. Whatever the layout, the same information has to be on the page:

• Mill name and the works that actually produced the coil
• Certificate number and date of issue
• Contract or purchase order number
• Heat or cast number, and the coil number for each coil covered
• Grade and the product standard, with its year
• Dimensions and coil mass
• Coating type, coating mass and surface treatment
• Chemistry block and mechanical block
• Named validator and signature block

If the mill is European you may instead see EN 10168 coded fields. The codes worth knowing are few:

B07 is the traceability field. A01 and A05 can be different parties, so read both.

Now the part almost nobody checks. EN 10346 clause 9.1 says the coil label must carry at least the name or mark of the manufacturer’s works, the designation, nominal dimensions, an identification number, the order number and the mass of the coil. The heat number is not on that list. JIS G3141 clause 12 is similar — it asks for a “manufacture number or inspection number”, not a heat number, and even that may be partly omitted “when approved by the purchaser.”

So the correct check on the godown floor is not “does the tag show the heat number” but “does the identification number on the tag tie back to a specific coil line on the certificate.”

Reconciling the certificate against the consignment

A certificate certifies conformity to a stated specification. That makes the paperwork itself worth reconciling before you argue about any single number:

• Count the coil lines on the certificate against the packing list and the actual coils landed. One certificate stretched across more coils than it lists covers nothing extra.
• Check whether the same heat number repeats across lots that were priced or offered separately.
• Check the certificate date against the bill of lading date. A certificate issued after shipment was not the basis on which the coil was released.
• Read the grade and quality description on the certificate against the description on the invoice and the goods declaration. They have to agree.

Where a trader sits between you and the mill, EN 10204 clause 6 is unambiguous: an intermediary “shall only pass on either an original or a copy of the inspection documents provided by the manufacturer without any alteration,” accompanied by means of identifying the product. Copies are allowed where traceability is operated, and the original delivered quantity may be replaced by the actual partial quantity delivered — nothing else may be changed.

Step 3: Check the grade against the right chemistry table

For hot-dip coated coil, EN 10346 Table 1 sets cast-analysis maxima.

The grade ladder in EN 10346 runs DX51D bending and profiling quality, DX52D drawing, DX53D deep drawing, DX54D special deep drawing, DX55D special deep drawing (+AS only), DX56D extra deep drawing, DX57D super deep drawing.

DX51D vs DX52D — the substitution to police

This one is invisible unless you compare tables. DX51D permits 50% more carbon (0.18 against 0.12), double the manganese (1.20 against 0.60) and 20% more phosphorus (0.12 against 0.10). On mechanicals it has no specified yield strength at all, a tensile band 80 MPa wider at the top, and 22% minimum A80 elongation against 26%. Material that passes as DX51D can still split on a deep press.

Why phosphorus and sulphur sit on every certificate

Sulphur segregates hard during solidification and forms FeS, causing hot shortness; sulphide inclusions lower weldability and corrosion resistance and can produce tears and cracks on reheating. Phosphorus segregates to prior-austenite and ferrite grain boundaries, which is the mechanism behind temper embrittlement and intergranular fracture.

Phosphorus is also a cheap strengthener. Total Materia notes that adding merely 0.17% phosphorus can raise both yield and tensile strength of low-carbon sheet by roughly 62 MPa while simultaneously decreasing ductility. That is how a high-phosphorus heat passes its tensile test on paper and then fails at the press.

Product analysis is allowed to exceed the cast figure

If you send a sample to a third-party lab and it comes back slightly over the certificate limit, that is not automatically a non-conformity. The MTC reports a cast analysis; your lab ran a product analysis. EN 10346 Table 5 allows a defined overshoot.

SPCC vs DC01 — the published sources genuinely disagree

SPCC to JIS G3141 and DC01 to EN 10130 are the two designations you will most often see written on cold rolled coil offers. Two things are worth knowing before you argue about a number.

First, JIS G3141 does not guarantee tensile values for plain SPCC. The standard states: “The tensile test value, as a rule, is not applicable to SPCC. When specified (SPCCT) by the purchaser, however, the values in parentheses shall be applied.” If you need guaranteed tensile figures, the order must say SPCCT — the T suffix is what buys the guarantee. The Melewar / Cold Rolling Industry (Malaysia) mill specification for JIS G3141 (1996) says the same.

Second, the published SPCC chemistry is not one number. Different documents give different limits, and each row below is reproduced as that document prints it.

Ignoring the obvious typo, the phosphorus limit still runs from 0.040 to 0.10 depending on which document the mill is working to. If phosphorus matters for your application, name the limit on the purchase order rather than relying on the grade symbol.

One Pakistani angle: PSQCA operates a compulsory-certification list which has covered “Cold Reduced Carbon Steel Sheet of Commercial and Drawing Qualities” to PS-ISO 3574 — the same ISO 3574 whose CR1 row gives C 0.15 / Mn 0.60 / P 0.05 / S 0.05. PSQCA amends the list over time, so check the current published version before you import rather than relying on any secondary summary, including this one.

GI ordered to JIS G3302: SGCC, SGCD and SGCH

Not all galvanized coil is ordered to EN 10346. GI is also written to JIS G3302, and its grade symbols do not map one-for-one onto the DX ladder — so if the certificate names JIS G3302, the DX chemistry and mechanical tables above are the wrong yardstick.

• SGCC is the commercial quality.
• SGCD (SGCD1 to SGCD4) are the drawing and deep-drawing qualities.
• SGCH is full hard — material not subjected to annealing, characterised in JIS G3302 by hardness rather than by tensile properties (HRB 85 minimum or HV 170 minimum).

SGCH is the one to watch. It is hard temper by definition, so it cannot be roll-formed or bent to the same radii as DX51D, and it carries no guaranteed elongation. A quotation that reads “SGCH” against a forming or profiling application is a specification error, not a bargain — and because full hard is cheaper, it is the substitution most likely to arrive unannounced.

Step 4: Mechanical results — and the footnotes that decide arguments

Four footnotes decide most arguments:

• Thin material gets a lower elongation bar. Table 6 allows minus 4 units for t ≤ 0.50 mm and minus 2 units for 0.50 < t ≤ 0.70 mm. DX51D at 0.45 mm needs only 18% A80, not 22% — a “low” result may be perfectly conforming.
• The DX52D yield ceiling depends on surface quality. SSAB’s published EN 10346:2015 table carries the footnote: “DX52D: this upper limit applies only to Surface quality B. For Surface quality A, the upper limit is 360 MPa.” So a DX52D result between 300 and 360 MPa is not automatically out of spec — check the surface quality letter on the certificate before raising a claim.
• r90 and n90 also flex with thickness. The minimum r90 value is reduced by 0.2 for t > 1.5 mm, and for t ≤ 0.70 mm the minimum r90 is reduced by 0.2 and the minimum n90 by 0.01. A 2 mm DX56D+Z returning r90 of 1.7 against the printed 1.9 is conforming.
• The guarantee expires. EN 10346 clause 7.2.1.3 guarantees mechanical properties for 1 month for DX51D, DX52D, DX53D and the construction grades; 3 months for bake-hardening and multiphase steels; 6 months for DX54D–DX57D and high-strength steels. On slow-moving stock, an in-spec certificate can be older than its own guarantee.

Also check how much steel one set of results is standing behind. EN 10346 clause 8.2: “The test unit consists of a maximum of 20 t or a fraction of 20 t of hot-dip coated flat products of the same grade and nominal thickness, coating mass and surface condition. In the case of strip, a coil weighing more than 20 t shall be regarded as one test unit.” Samples come from the beginning or the end of the coil, with the tensile sample at least 50 mm from the edge — the middle of the coil is never tested.

And under clause 8.3, tensile properties and coating mass may be determined “by calculation in accordance with an approved method” if that was agreed at order stage. A calculated number is not a lie; it is just not a measurement.

Step 5: Z275 coating mass — total or per side, and what it is in microns

EN 10346 clause 7.9 is explicit: the coating mass values “apply for the total mass of the coating on both surfaces for the triple spot test and the single spot test.” Z275 means 275 g/m² across both faces, not per face. Aisha Steel writes “(double sides)” next to the coating weights in its own published HDGC range, which removes the ambiguity on that mill’s paperwork at least.

In the table below, the coating masses are EN 10346 Table 11 values. The thickness column is calculated from those masses and the coating densities the standard itself gives, using the standard’s own formula — it is not a separate published column, so it stays internally consistent.

Converting coating mass to microns

EN 10346 gives the conversion as: thickness in µm per surface = coating mass in g/m² (both surfaces) ÷ (2 × coating density in g/cm³). The standard’s own worked example is 100 g/m² both surfaces ≈ 7.0 µm per surface for zinc at 7.1 g/cm³, which is what the formula returns.

The density is the part people get wrong, and the two aluminium-bearing coatings are not the same material:

• AZ (55% aluminium-zinc, galvalume) runs at 3.8 g/cm³. AZ150 is therefore about 19.7 µm per surface, where a zinc coating of the same 150 g/m² would be about 10.6 µm.
• ZM / ZAM (zinc-aluminium-magnesium) is a zinc-based coating, not a galvalume. Its density under EN 10346:2015 is about 6.2 g/cm³, so ZM120 works out near 9.7 µm per surface. Applying the galvalume constant of 3.8 to a ZM coating would overstate the thickness by roughly 60%.

Never carry one constant across coating families. Read the coating type off the certificate first, then use that coating’s own density — see our note on ZAM and aluminium-zinc coated coil for where each is used.

What is actually guaranteed on one side

The coating is not split evenly, and the per-side figure is weaker than most buyers assume. EN 10346 says only that “it may be assumed that a coating mass of at least 40% of the value given in Table 11 for the single spot test exists on each surface.” That is a permitted assumption, not a specified minimum. For Z275 it works out at 0.40 × 235 = 94 g/m² on one side. ASTM A653/A653M carries the same 94 g/m² figure as a “normally not less than” footnote rather than a hard limit.

If you need a genuine per-side guarantee — for a painted or PPGI substrate, for instance — agree a per-surface minimum at order stage. Do not assume the standard has given you one.

G90 vs Z275: the ASTM notation trap

Get the notation the right way round. In ASTM hot-dip designations, the letter before the numerals (G90, Z275, A40, ZF120) means total both sides; numerals before the letter (60G60G, 40G40G, 45A45A) mean per side. GalvInfo Note 1.1 sets this out: the G and Z forms are the ASTM A653/A653M Table 1 total-both-sides designations, while the repeated numeric forms are the Table S2.1 per-side designations.

At the conversion constant of 1.00 oz/ft² = 305 g/m², G90 is 274.5 g/m² — commercially interchangeable with Z275, but not numerically identical. The one-side figures differ too: 0.32 oz/ft² is 97.6 g/m² against Z275’s 94 g/m². On a marginal single-spot result, argue against the specification actually named on the order, not against the one you think it equals.

GalvInfo also flags that G and Z swap meaning between the hot-dip and electrogalvanized ASTM specs: for hot-dip, G (preceding the numerals) is inch-pound and Z is SI, both total-both-sides; for electrogalvanize, G (following the numerals) is SI and Z is inch-pound, both single-spot single-side.

Light coatings and JIS symbols

The EN table above starts at Z100, but coatings lighter than that exist and are quoted under a different symbol system. In JIS-style symbols the numerals are multiplied by ten to give grams per square metre total both surfaces. Aisha Steel publishes its hot-dip galvanized range as Z06–Z27 alongside the ASTM equivalents G30–G90 — so the range on offer starts well below the lowest EN row above.

On that system a “Z12” is 120 g/m² total both surfaces, and a “Z27” is 270 g/m² — within a few grams of EN Z275 and ASTM G90, despite looking an order of magnitude smaller. Read the standard named on the certificate before you read the coating symbol, and convert every offer to g/m² total both surfaces before you compare prices. Two quotes are not comparable until they are on the same basis.

Slit coil and the triple spot test

One more point, relevant to any narrow material: the triple-spot test applies only to the original, full-width, as-coated sheet. Narrow sheet cut from full-width sheet is subject only to a minimum single-spot, total-both-sides requirement. Judging slit coil against a TST figure is technically wrong.

Step 6: The certificate is a customs document too

Grade, coating, width and origin as written on the paperwork carry duty consequences in Pakistan, so a “helpful” re-description on a certificate or invoice is not a small favour.

Anti-dumping duty on galvanized and galvalume from China

Pakistan imposed anti-dumping duties on galvanized steel coils and sheets from China in 2017, at rates reported as 6.09% to 40.47%, and extended them in 2022 following a sunset review. In 2025 the National Tariff Commission concluded an anti-circumvention investigation — brought by International Steels and Aisha Steel Mills — and extended the 40.47% rate to hot-dip zinc-aluminium (galvalume) coated coils and sheets from China, covering material 0.15 mm to 2.75 mm thick and 600 mm or more wide, under PCT headings 7210.6110, 7210.6190, 7210.6910 and 7210.6990. The NTC found galvalume had “the same essential physical and chemical characteristics” as the galvanized product already covered. These figures are as reported by The Express Tribune on 1 July 2025.

Anti-dumping measures run in five-year terms and are re-examined at sunset review. Confirm the current status and expiry of any measure on the NTC’s own notifications page before you fix a shipment date — do not plan a Q1 arrival around a duty you assume has lapsed. Our note on anti-dumping duty on galvanized steel goes into the background.

Why the mill name on the certificate decides your duty rate

This is the point that ties the certificate to the money. NTC anti-dumping rates are exporter-specific, not a single country-wide number: the lower rates apply to named cooperating producers, and the top rate is the residual applied to all other exporters and foreign producers. A range of 6.09% to 40.47% is not a band your clearing agent negotiates within — it is a lookup against a name.

The practical rule follows directly. The works named on the mill test certificate must match the producer named in the NTC notification and the exporter named on the Form E and the certificate of origin. Any mismatch — trader-name invoicing, a third-country routing, a retyped or “cleaned up” certificate — pushes the consignment to the residual rate on the whole lot. Reading the certificate for the producer’s identity is worth more money on a container than every chemistry check in Steps 3 and 4 put together.

Width, headings and quality description

Two classification points are worth holding in mind. First, the flat-rolled coated headings split at width: 7210 covers product 600 mm and wider, and narrower material falls under 7212. Slitting to change a heading is a known practice and an audited one — and it is the same 600 mm boundary that determines whether the galvalume anti-circumvention measure above bites at all. It also connects back to the slit-coil point in Step 5: narrow material changes both what you can test it against and what heading it clears under.

Second, prime versus secondary is declared under different PCT sub-headings and attracts different duty, so the quality description is a customs question as much as a technical one. Rates, regulatory duty and additional customs duty have changed repeatedly under the National Tariff Policy, so this article deliberately quotes no rate: price your shipment off the current Pakistan Customs Tariff and a current NTC check, not off any published article. If you are importing flat steel from China, the certificate description, the invoice and the goods declaration must all agree.

Frequently asked questions

Is a 2.2 test report good enough for a building project?

It depends entirely on whether your consultant or client accepts non-specific inspection. A 2.2 carries genuine test results, but under EN 10204’s own definition the products inspected “are not necessarily the products actually supplied.” Acton Bright Steel’s published guidance on the certificate types puts the practical position plainly: results from another coil of the same cast, made by the same process route, can be used. If the specification calls for 3.1, a 2.2 will not satisfy an audit — and the time to discover that is at enquiry stage, not at inspection.

The certificate says DX51D but I ordered DX52D. Is it acceptable?

Not without your written agreement, and usually not for pressing work. DX51D is bending and profiling quality; DX52D is drawing quality. DX51D permits 0.18% C against 0.12%, 1.20% Mn against 0.60%, has no specified yield strength, and needs only 22% A80 against 26%. For roll-forming the substitution may be harmless. For anything drawn, it is not.

Why does the coil tag not show the heat number?

Because no standard cited here requires it. EN 10346 clause 9.1 mandates the works name or mark, the designation, nominal dimensions, an identification number, the order number and the coil mass. JIS G3141 clause 12 asks for a “manufacture number or inspection number.” What you should insist on is that whatever number the tag carries can be traced to a specific line on the certificate.

Does Z275 mean 275 g/m² on each side?

No. EN 10346 treats the coating number as the total across both surfaces. On one surface the standard says only that at least 40% of the single-spot value may be assumed, which for Z275 is 94 g/m² — an assumption, not a guaranteed floor. If you need a per-side minimum, write it into the order. See our overview of GI, PPGI and galvalume roofing sheet for how this plays out in the roofing trade.

Can a trader issue its own mill test certificate?

No. EN 10204 clause 6 requires an intermediary to pass on the manufacturer’s inspection document, original or copy, “without any alteration,” with product identification attached. Copies are permitted where the intermediary operates traceability and can produce the original on request, and the only permitted change is replacing the original delivered quantity with the actual partial quantity supplied.

Can I get a mill test certificate for secondary coil?

Be careful here. A certificate states conformity to a named specification, so a clean prime certificate presented against a secondary-priced offer is a reason to reconcile the paperwork rather than a reassurance. Check that the coil count and coil numbers on the certificate match the packing list and the coils actually landed, that the heat number is not repeating across separately priced lots, and that the quality description on the certificate matches the invoice and the goods declaration. Prime and secondary also sit under different PCT sub-headings, so a mismatch is a customs exposure as well as a quality one.

My third-party lab result is slightly above the certificate’s carbon limit. Is the coil rejectable?

Possibly not. The MTC reports a cast analysis; your lab ran a product analysis. EN 10346 Table 5 permits a product analysis to exceed the cast limit by +0.02 for C (≤0.32), +0.10 for Mn (≤2.50), +0.01 for P (≤0.12) and +0.005 for S in the 0.015–0.045 band. Compare against the deviated limit before raising a claim.

Sources

Standards are cited by number, edition and clause. Copyright standards are not reproduced or linked here — buy them from the issuing body or its national distributor.

• EN 10204:2004 — Metallic products, types of inspection documents (clauses 2.1, 2.2, 4.1, 5, 6)
• EN 10168:2004 — Steel products, inspection documents, list of information and description (field groups A, B, C, Z)
• EN 10346:2009 and EN 10346:2015 — Continuously hot-dip coated steel flat products (Tables 1, 5, 6, 11; clauses 7.2.1.3, 7.9, 8.1.1, 8.1.3, 8.2, 8.3, 9.1)
• EN 10130 — Cold rolled low carbon steel flat products for cold forming (DC01)
• JIS G3141 — Cold-reduced carbon steel sheets and strip (SPCC / SPCCT, clause 12)
• JIS G3302 — Hot-dip zinc-coated steel sheet and strip (SGCC, SGCD, SGCH)
• ASTM A653/A653M, ASTM A792/A792M, ASTM A879M — coating designations and coating mass requirements
• ArcelorMittal — Hot-dip galvanised steel, catalogue E20
• ArcelorMittal — Magnelis zinc-aluminium-magnesium (ZM) coated steel, catalogue E35
• SSAB — Metal coated formable steels (EN 10346:2015), including the DX52D surface-quality footnote
• GalvInfo Note 1.1 — Coating designations and weights
• Melewar / Cold Rolling Industry (Malaysia) — JIS G3141 product specification
• China Steel & Nippon Steel Vietnam — cold rolled catalogue
• China Steel & Nippon Steel Vietnam — hot-dip zinc-coated catalogue
• steelnumber.com — DC01 composition entry (secondary database)
• Acton Bright Steel — BS EN 10204 certificate types
• The Express Tribune, 1 July 2025 — Duty on Galvalume steel imposed
• National Tariff Commission — anti-dumping notifications (check current status of any measure)
• Aisha Steel Mills — published product range and coating designations
• PSQCA — list of compulsory items to meet Pakistan standards
• NPTEL — effect of sulphur in steel
• Total Materia — effect of phosphorus in carbon steels

Buying imported or locally rolled flat steel?

The single cheapest thing you can do on your next order is to name the EN 10204 document type, the product standard with its edition year, and the coating mass in g/m² total both surfaces — in the purchase order and in the LC, before the LC is opened. Almost every problem in this article is a specification that was never written down.

Raw Easy Corp trades flat steel in Karachi. See Aisha Steel CRC, ISL GP coil and the full products list. Contact Raw Easy Corp.