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Mill test report (MTR) reader: check the heat, chemistry and strength against spec
A mill test report (MTR), also called a mill test certificate (MTC) or material test report, is the document a mill issues with each heat of steel or aluminum: the heat number, the spec and grade, the chemistry and the mechanical test results. Paste the text of an MTR below, or upload the PDF or a photo, and the reader pulls out every value and checks it against the published limits for A36, A572 Grade 50, A992, A500 Grade B and C, 304/304L and 6061-T6. You get pass, fail or check per element, the questions to ask the supplier, and a one-page MTR review record to file. Morsa, the AI system for manufacturers, does this filing for you at receiving.
Updated October 21, 2026
What is a mill test report?
A mill test report certifies that a heat of metal meets the specification it was ordered to. The mill melts a batch (a heat), casts and rolls it, tests samples, and prints the results on the MTR with the heat number. The heat number is stamped, stenciled or tagged on the material too, and that number is what ties a piece of steel on your floor to its cert. Buyers, fabricators and inspectors read the MTR to confirm the material is what the drawing and the purchase order call for, and they keep it as the traceability record.
Mill test certificate, material test report, mill cert, MTC and material certification all mean the same document in day-to-day use. A certificate of conformance (CoC) is different: it is the seller’s signed statement that the goods meet the order, usually without test data.
What is on an MTR, and what to check
| Field | What it tells you | What to check |
|---|---|---|
| Heat number | The melt the material came from | It matches the number on the material and on the packing slip |
| Specification and grade | The standard the mill certifies, such as ASTM A36 or A500 Grade C | It matches your PO and drawing, including dual certs like A36/A572-50 |
| Chemistry | Weight % of carbon, manganese, phosphorus, sulfur, silicon and alloying elements | Each element is inside the spec’s limits |
| Mechanical properties | Yield strength, tensile strength, elongation, sometimes hardness or impact tests | Each meets the minimum (and maximum, where one applies), in the right unit |
| Size and product form | Thickness, width, length, or tube size and wall | It matches what arrived |
| Country of melt and manufacture | Where the steel was melted and where it was rolled | Domestic melt if your customer requires DFARS or Buy America |
| Certification statement and type | Who certifies the results, often EN 10204 3.1 | The type your customer asked for, signed or validated by the mill |
How to read a mill test report, step by step
Match the heat number. Find it on the MTR and on the bundle tag or stencil. If they differ, stop: the cert does not belong to this material.
Read the spec line. The MTR must name the spec and grade on your PO. A cert for A36 does not prove A572 Grade 50, even when the numbers would pass.
Check the units. Chemistry is in weight %, sometimes printed x100 or x1000 (carbon 18 means 0.18%). Strength is in ksi, psi or MPa; 1 ksi = 1,000 psi = 6.895 MPa.
Compare chemistry to the limits. Carbon, manganese, phosphorus and sulfur are the usual limits on carbon steel; chromium and nickel on stainless; magnesium and silicon on 6061. Round each value to the last digit of its limit before comparing, as ASTM E29 does.
Compare the mechanicals. Yield and tensile against their minimums, elongation against its minimum for the gauge length tested (2 in or 8 in).
Read origin and cert type. Note where it was melted and manufactured, and whether it is an EN 10204 3.1 inspection certificate or a lesser 2.2 report.
File it against the PO and the heat. The cert is only useful later if someone can find it by heat number when a customer asks.
The reader above does steps 2 to 6 for you and leaves the match to the physical material, which only someone at receiving can do.
EN 10204 types: 2.1, 2.2, 3.1 and 3.2
| Type | Name | What it contains | Validated by |
|---|---|---|---|
| 2.1 | Declaration of compliance with the order | A statement only, no test results | The manufacturer |
| 2.2 | Test report | Results from non-specific inspection (typical values, not your heat) | The manufacturer |
| 3.1 | Inspection certificate 3.1 | Results from specific inspection of the delivered material | The manufacturer’s authorized inspection representative, independent of manufacturing |
| 3.2 | Inspection certificate 3.2 | Results from specific inspection, witnessed | The manufacturer’s representative and the purchaser’s representative or an inspector named in the regulations |
Old certs say 3.1B, the name in the earlier DIN 50049 standard; it corresponds to 3.1.
When a customer asks for a “3.1 cert” or an “EN 10204 3.1 certificate”, they want test results from your actual heat, signed off by the mill’s inspection department. A 2.2 test report will be rejected.
Spec limits the reader checks
| Spec and grade | Carbon max, % | Yield min | Tensile min | Source |
|---|---|---|---|---|
| ASTM A36 (plate, bar, shapes) | 0.25 (0.29 thick plate) | 36 ksi (250 MPa) | 58 ksi (400 MPa) to 80 ksi | Public source |
| ASTM A572 Grade 50 | 0.23 | 50 ksi (345 MPa) | 65 ksi (448 MPa) | Public source |
| ASTM A992 (wide-flange shapes) | Not built in | 50 ksi (345 MPa) | 65 ksi (450 MPa) | Public source |
| ASTM A500 Grade B (structural tube) | 0.26 | 42 ksi (290 MPa) round, 46 ksi (315 MPa) shaped | 58 ksi (400 MPa) | Public source |
| ASTM A500 Grade C (structural tube) | 0.23 | 46 ksi (315 MPa) round, 50 ksi (345 MPa) shaped | 62 ksi (425 MPa) | Public source |
| ASTM A513 (mechanical tube) | Not built in | Not built in | Not built in | Set by the steel grade on your PO |
| 304/304L stainless, dual certified (ASTM A240) | 0.03 | 30 ksi (205 MPa) | 75 ksi (515 MPa) | Strengths not confirmed in a public source: shown as check, never fail |
| 304L stainless (ASTM A240, UNS S30403) | 0.03 | 25 ksi (170 MPa) | 70 ksi (485 MPa) | Strengths not confirmed in a public source: shown as check, never fail |
| 304 stainless (ASTM A240, UNS S30400) | 0.07 (0.08 thick plate) | 30 ksi (205 MPa) | 75 ksi (515 MPa) | Strengths not confirmed in a public source: shown as check, never fail |
| 6061-T6 / T651 aluminum sheet and plate (ASTM B209) | Not built in | 35 ksi (240 MPa) | 42 ksi (290 MPa) | Public source |
| 6061-T6 / T6511 aluminum extrusion (ASTM B221) | Not built in | 35 ksi (240 MPa) | 38 ksi (260 MPa) | Public source |
ASTM standards are copyrighted, so only the numeric limits are stored, each cited to a public source. Confirm against the current edition of the standard and your PO.
Where public sources disagree, for example A36 carbon by plate thickness or 304 silicon in sheet versus bar, the reader passes the loosest published limit and marks the value “check” with a note, so you look before you accept it. A limit we could not confirm in a public source can only produce “check”, never “fail”.
ksi, psi and MPa
| ksi | psi | MPa |
|---|---|---|
| 25 ksi | 25,000 psi | 172 MPa |
| 36 ksi | 36,000 psi | 248 MPa |
| 42 ksi | 42,000 psi | 290 MPa |
| 46 ksi | 46,000 psi | 317 MPa |
| 50 ksi | 50,000 psi | 345 MPa |
| 58 ksi | 58,000 psi | 400 MPa |
| 65 ksi | 65,000 psi | 448 MPa |
1 ksi = 1,000 psi = 6.894757 MPa. A yield of 361 labeled ksi is almost certainly MPa; the reader flags it.
Common MTR problems and what to do
No heat number, or one that does not match the tag. Ask the supplier for the cert of the heat you received. Do not use the material on a traceable job until it matches.
Wrong spec on the cert. A cert proves only the specs it names. Ask for a cert to your spec, or a dual cert.
Typical values instead of heat results. A 2.2 report or a data sheet is not an MTR for your heat.
Unit confusion. MPa printed under a ksi heading, or chemistry printed x100 without saying so. Read the column heading, then ask the mill if it is unclear.
Missing country of melt. Defense and infrastructure customers need it. Ask before you ship, not at audit.
Two heats on one cert. Common on bundles. Each piece’s tag must match one of the heats listed.
MTR, CoC or CoA: which one does the customer want?
| Document | Who issues it | What it proves |
|---|---|---|
| Mill test report (MTR) | The mill that made the metal | The heat’s chemistry and test results meet the spec |
| Certificate of conformance (CoC) | Your company, as the seller | The parts shipped meet the PO, drawing and specs |
| Certificate of analysis (CoA) | The producer or a lab, per lot | A lot’s tested properties, common for chemicals, food and pharma |
Most customers want the MTR and your CoC together in a cert packet. The material cert packet checklist lists what each industry asks for, and the certificate of conformance template writes the CoC.
Where Morsa fits: certs filed at receiving, not hunted for later
Today the cert work is manual. Receiving scans the MTR, names the file, and maybe types the heat number into the ERP. Months later a customer asks for the cert packet on an order, and someone hunts through email and shared drives for the right heats, then emails the supplier for the one cert nobody saved.
Morsa does that work while your team approves. When receiving posts a phone photo of the packing slip, Morsa turns it into the ERP receipt and saves the mill cert against the PO and the heat number. When a customer asks for the certs on an order, Morsa builds the packet from the heats that actually shipped, sees the cert that is missing, requests it from the supplier, and sends the finished packet once it arrives.
That is the difference between an AI system like Morsa and a folder of PDFs: nobody types the cert in, and nobody chases it. Morsa runs on the ERP and inbox you already have, with no new software for receiving to learn. At JRG Automotive, Morsa caught 5 of 8 production-stopping shortages early, about $2M saved.
Common questions
Is a mill test certificate the same as a mill test report?
Yes. Mill test report, mill test certificate, material test report, mill cert and MTC are names for the same document. EN 10204 calls the common type an inspection certificate 3.1.
What does “melted and manufactured in the USA” mean?
The steel was melted and then rolled or formed in the United States. US defense contracts restrict specialty metals by where they were melted (DFARS 252.225-7009), and Buy America rules on public projects look at where steel was produced, so customers on those jobs ask for it on the cert.
Can I upload a scanned or photographed MTR?
Yes. Upload a PDF or a phone photo up to 6 MB and the reader returns the same fields. Check the values against the image before you sign off, since scans can be hard to read.
Why does a value say “check” instead of pass or fail?
Either the limit depends on something the cert does not say (plate thickness, tube shape, gauge length), or the limit comes from a source we could not confirm publicly. Read the note beside it and confirm against your spec.
Is my cert stored?
The quick read runs in your browser. For the full read, the text or file goes to Morsa’s server, which returns only values it finds on the cert and stores and logs nothing. The pass and fail check and the PDF are made on your device.
How do I know a cert is genuine?
Buy from suppliers who can trace the heat to the producing mill, check that the heat on the cert matches the material, and on critical jobs ask the mill to confirm the cert number or test a sample yourself. An MTR with round numbers, a missing heat or a spec that does not match the product is worth a phone call.
Related tools
Sources
Wikipedia, A36 steel (chemistry table and strength, citing ASTM A36/A36M)
Wikipedia, ASTM A500 (grade table citing ASTM A500/A500M-07)
Wikipedia, SAE 304 stainless steel (ASTM A276 table and carbon by grade)
AZoM, Stainless Steel Grade 304 (UNS S30400) chemistry table
Wikipedia, 6061 aluminium alloy (composition and tempers, citing ASTM B209 and B221)
WHERE MORSA FITS
Certs filed when the steel arrives. Packets built when the customer asks.
Morsa saves the mill cert the moment the packing-slip photo becomes the receipt, ties each heat to its lot, builds your customer’s cert packet and requests any missing cert from the supplier. It works in email, Teams, WhatsApp or whatever you already run on.
