Mill Test Report (MTR) Practical Guide: How to Read Any Stainless Steel MTR Using a Real 6Cr13 Cert
Imagine you’ve just received a shipment of stainless steel worth hundreds of thousands of dollars — maybe 304 sheet, 316L tube, or a martensitic strip like 6Cr13. The warehouse is pushing for check-in, production is waiting on scheduling, and then your customer or internal QC asks:
What determines whether you can answer with confidence isn’t whether you have a stamped piece of paper — it’s whether you actually understand what’s on that mill test report. This guide uses a real 6Cr13 cold-rolled strip MTR issued by Jiuquan Iron & Steel (Group) Hongxing Steel Co., Ltd. (JISCO) to build a universal MTR review template, so you can stop falling into material substitution traps for good.
Why You Need to Read MTRs, Not Just Collect Them
Stainless steel grades look nearly identical: 304, 316L, 410, 6Cr13, and duplex grades are almost impossible to tell apart by eye. What actually determines whether a material is fit for use is its chemical composition and mechanical properties — and both live in the mill test report.
If you only confirm “there’s a certificate” without checking the data on it, you’re essentially accepting material blind. When grade mix-ups or underperforming properties surface later, the liability lands on procurement or QC. Knowing how to read an MTR puts you in control of three critical moments:
- Goods receipt: Confirm the physical material matches the documentation one-to-one
- Engineering review: Determine whether the material meets design and service requirements
- Audit: Demonstrate that you actually carried out your quality verification responsibilities
Below, we’ll first clarify what an MTR is and what it contains, then walk through a hands-on review using that 6Cr13 cert.
What Is a Mill Test Report (MTR)? What Does It Actually Certify?
A mill test report (MTR) is a quality document issued by a steel mill or authorized producer that records — by heat number — whether a batch of material meets the specified standard for chemical composition and mechanical properties. Its core function is material traceability and compliance certification.
At the top of this 6Cr13 MTR, you’ll find the following key fields:
- Producer: Jiuquan Iron & Steel (Group) Hongxing Steel Co., Ltd.
- Product: Cold rolled stainless steel strip
- Grade: 6Cr13
- Standard: Q/JGBXG002-2023
- Delivery condition: Annealed
- Surface finish: 2B
- Total quantity: 9.233 MT
This means the MTR formally declares: this 9.233 MT coil of 6Cr13, 2 mm × 1219 mm cold-rolled strip was produced and tested in conformance with Q/JGBXG002-2023. Everything in the tables below simply backs up that declaration with actual numbers.
Is an MTR the Same as a Material Certificate?
In everyday usage, “MTR” and “material certificate” are often used interchangeably — but strictly speaking, an MTR typically refers to a complete traceability document with heat number, measured test data, and full traceability, while some basic material certificates may only state “conforms to standard X” with no supporting data.
The more practical way to judge is by content, not name:
- Does it include a heat number, coil number, or other traceability identifiers?
- Does it list actual measured values for chemical composition and mechanical properties?
- Does it specify the applicable standard and certificate type (e.g., EN 10204 3.1)?
What If a Supplier Can’t Provide an MTR?
The answer is clear: in virtually all industrial and commercial applications, using stainless steel without an original mill test report is not acceptable.
We’ve received countless messages from buyers who were defrauded by Chinese traders — lured by low prices into buying stainless steel coil with no documentation at all. They ordered 304 and received 201. By the time they found out, the seller was either in denial or had disappeared entirely.
In laboratory construction, chemical equipment manufacturing, or export trade, any undocumented material will cause the entire project to fail acceptance.
If your supplier cites “loose stock” as a reason for not providing an MTR, it likely means the material has changed hands multiple times, the original data is lost, or it’s simply off-spec scrap. If a material failure occurs, there will be no legal trail back to the original producer.
In this situation, you have only two options:
- Reject the shipment outright — avoid blocking the production flow later
- Third-party lab testing (PMI): If use is unavoidable, commission an independent chemical composition and tensile test at your own cost and obtain a new report — but this generally cannot fully replace the authority of an original mill MTR
What Does a Stainless Steel MTR Typically Contain?
Formats vary by mill, but the core structure is consistent. Using this 6Cr13 cert as a reference, it breaks down into several sections:
- Header information: Mill name, address, product name, grade, standard, delivery condition, surface finish, total quantity
- Order and logistics info: Consignee, wagon number, certificate number, date
- Batch identification: Coil No., Heat No., piece count
- Dimensions and weight: Thickness, width, length or coil weight, theoretical weight
- Chemical composition table: C, Si, Mn, P, S, V, Cr, Ni, N and other element percentages
- Mechanical properties table: Rp0.2 (yield strength), Rm (tensile strength), A (elongation), HV (hardness)
- Compliance statements: EN 10204 3.1 declaration, after-sales terms, complaint window, anti-counterfeit code
- Signatures and stamps: Quality department seal, authorized signatory
What Is a Heat Number and Why Does It Matter?
A heat number is the unique identifier a steel mill assigns to each melt, used to trace that heat’s production, testing, and quality data. All chemical composition and mechanical property records are tied to the heat number.
In this 6Cr13 MTR’s data table, you can see:
- Coil No.: 24A03500Z-W5NM
- Laufnummer: 4722272
- Thickness: 2 mm
- Width: 1219 mm
- Pieces: 1
- Theoretical weight: 9.233 MT
This means the composition and property data on this certificate is only valid for “Heat 4722272, Coil 24A035002-W56M — this one 9.233 MT coil.” If another heat number shows up in the same shipment sharing this MTR, that’s a major red flag.
Once you understand these sections, you have a map — you’ll know exactly where to look for each piece of information.
Step 1: How to Confirm This MTR Actually Matches Your Shipment
The first thing to do when you receive an MTR is not to check the composition — it’s to verify that this document corresponds to the physical material in front of you, and to make this a fixed SOP.
In this order, the customer purchased a batch of 6Cr13 cold-rolled stainless steel strip: 2 mm thick, 1219 mm wide, 9.233 MT theoretical weight, produced to standard Q/JGBXG002-2023. Our MTR reflects each of these agreed parameters in full, one-to-one.
- Is “cold rolled stainless steel strip” explicitly stated?
- Is the grade listed as “6Cr13”?
- Is the applicable standard consistent with the contract (is Q/JGBXG002-2023 within your project’s accepted scope)?
- Do the delivery condition (Annealed) and surface finish (2B) match the technical requirements?
Under the product dimensions section, this MTR states:
- Thickness: 2 mm
- Width: 1219 mm
- Pieces: 1
- Theoretical weight: 9.233 MT
Cross-check these figures against your purchase order, technical agreement, and production plan to confirm that spec, quantity, and total weight all match exactly.
- Record the Coil No. and Heat No. from the MTR
- Go to the warehouse and physically check the spray-marked or stamped identifiers on each coil
- Confirm that every physical coil’s heat number and coil number has a corresponding entry in the MTR
If any coil in the shipment carries a heat number not listed in the MTR — or if a single MTR is trying to cover multiple unrelated heats — halt goods receipt or production immediately, request complete documentation from the supplier, and decide whether to accept after re-confirming the batch.
Once you’ve confirmed the paperwork matches the physical material, you can move on to the most important question: is this actually the grade you ordered?
Choose Your Reference Standard First
You can’t judge composition by feel — you need clear numerical limits. Common sources include:
- National or international standards (ASTM, EN, GB, JIS grade composition requirements)
- Mill proprietary standards such as Q/JGBXG002-2023 in this MTR
- Composition range clauses in the purchase contract or project technical specification
In public references, 6Cr13 is generally treated as equivalent to X6Cr13 / 1.4000, a martensitic stainless steel with typical requirements of:
- C no higher than approximately 0.08%
- Cr in the 12–14% range
- Upper limits on Mn and Si
- Strict maximums on P and S
You don’t need to memorize every value — but internalize the principle: every grade has an “allowed window,” and every element’s measured value must fall within it.
Running a Composition Check on This 6Cr13 MTR
For Heat 4722272, the chemical composition data reads approximately:
| Element | Wert |
|---|---|
| C | 0.067% |
| Si | 0.44% |
| Mn | 0.63% |
| P | 0.024% |
| S | 0.001% |
| V | 0.117% |
| Cr | 12.98% |
| Ni | 0.98% |
| N | 0.067% |
Comparing these against the standard:
- C is well below the upper limit, reducing brittleness risk after hardening
- Cr falls within the 12–14% range, ensuring basic corrosion resistance and strength potential
- P and S are both low, contributing to improved toughness
- Ni and N additions are consistent with a typical 6Cr13 chemistry
From a composition standpoint, this material’s identity as 6Cr13 is credible. For 304, 316L, or 2205, just swap in the relevant standard limits and run the same check.
How Do You Know If a Composition Value Is “Acceptable”?
A value is acceptable as long as it falls within the upper and lower limits set by the standard or technical agreement. If a key element is clearly below its minimum or sitting right at the boundary, flag it.
In practice:
- List each element’s allowed range alongside its measured value in a table
- Mark elements that are “near the lower limit” or “near the upper limit”
- Log those boundary cases separately, and arrange re-testing or build in a larger process safety margin if needed
Step 3: How to Use Mechanical Properties to Judge Fitness for Use
Chemical composition tells you “is this 6Cr13” — mechanical properties answer “can this 6Cr13 handle your application.”
The Four Key Indicators
On the right side of this 6Cr13 mill test report, you’ll find:
- Rp0.2 (Yield Strength): 413 MPa
- Rm (Tensile Strength): 708 MPa
- A (Elongation after fracture): 24.0%
- HV (Vickers Hardness): 206
These four numbers collectively describe the material’s strength and ductility state.
How to Interpret This 6Cr13 Property Data
- 413 MPa yield strength indicates solid load-bearing capacity under normal service conditions
- 708 MPa tensile strength is within the typical range for martensitic stainless steel, suitable for many structural and blade applications
- 24% elongation is good ductility for cold-rolled strip, favorable for subsequent stamping and bending
- HV 206 hardness is a common level for annealed 6Cr13 in many applications
But the real task is to evaluate these four numbers against two reference points:
Against drawing or design requirements:
- What are the minimum Rp0.2, minimum Rm, minimum A, and maximum hardness specified?
- If the MTR values fall clearly outside these ranges, consult the engineer immediately
Against historical data for the same grade:
- Review your previous 6Cr13 MTRs OR 304, 316 that you have ordered
- If this batch’s yield strength or hardness is significantly higher than the historical average, the processing condition has changed — consider running process trials or re-testing
Which Matters More — Yield Strength or Tensile Strength?
In most structural design work, yield strength is more critical because it directly determines whether the material will permanently deform under normal working loads. Tensile strength is primarily used to assess ultimate load capacity and safety factors.
When reviewing an MTR, follow this priority order:
- Check whether Rp0.2 exceeds the drawing’s minimum requirement
- Confirm Rm is within a reasonable range
- Use elongation and hardness together to assess whether ductility and machinability meet process needs
What Does Hardness That’s Too High or Too Low Mean?
Higher hardness generally means greater strength and wear resistance, but potentially more brittleness and harder machinability. Lower hardness means easier processing, but possibly insufficient wear resistance and fatigue strength.
For example:
- For wear parts like blades and bearings, you’d prefer higher hardness
- For parts requiring significant deformation in deep drawing, ductility and lower hardness matter more
This 6Cr13 at HV 206 is within an acceptable range for general blade, spring, or high-strength structural applications. For extreme deep drawing, evaluate carefully.
Step 4: Does Certificate Type (2.2, 3.1, 3.2) Affect Your Material Assessment?
In the English notes at the bottom of the 6Cr13 MTR, you’ll typically find a statement along the lines of “this certificate complies with EN 10204 3.1,” indicating this is a Type 3.1 certificate under the EN 10204 system, issued by the mill’s own quality department.
What’s the Difference Between EN 10204 3.1 and 3.2?
A 3.1 certificate is issued by the manufacturer’s own quality department based on their internal test data. A 3.2 certificate requires a third-party inspection body or the purchaser’s representative to co-witness and validate the results — it carries greater authority and oversight.
For your day-to-day MTR review:
- The certificate type doesn’t change what you look for or in what order
- But it does affect who bears responsibility if something goes wrong, and which project compliance requirements are satisfied
For most standard projects, a 3.1 certificate is sufficient. A 3.2 is only specifically required for very high-risk applications or strict regulatory environments.
Many suppliers attempt to pass off a 3.1 certificate as a 3.2. Remember — a genuine 3.2 MTR must carry two independent stamps: the mill’s quality seal plus a third-party inspection body’s stamp. If there’s only the mill’s own stamp, even if the document states “Comply with 3.2,” it is an invalid misrepresentation.
Summary: Turning “Reading One 6Cr13 MTR” Into a Universal Template for Any Stainless Steel
The key to upgrading MTR review from “gut feel” to “repeatable process” is converting the steps above into a simple one-page checklist and applying it consistently across your team.
Here’s how to structure that checklist:
Identity Confirmation:
- Product name, grade, and standard match the purchase order
- Dimensions and quantity match
- Heat number and coil number correspond one-to-one with the physical material
Grade Verification (Composition):
- Every element falls within the standard or technical agreement limits
- Any boundary-case elements are identified and logged
Performance Verification (Mechanical + Hardness):
- 2, Rm, A, and hardness meet drawing requirements
- Values are within reasonable variation of historical data for the same grade
Document Compliance:
- Certificate header identifies a genuine mill or authorized producer
- Certificate type (3.1, 3.2, etc.) meets contractual requirements
- Stamp, date, and anti-counterfeit elements are all present
When warehouse, QC, and procurement all work from the same checklist, you move from “a certificate exists, so we’re fine” to “I understand what every line of data means, and I know when to ask a follow-up question or run another test.” This approach works not just for 6Cr13 — it applies equally to MTR review for 304, 316L, 2205, and all duplex stainless steel grades.
References & Further Reading
- Merit Brass – How to Read a Material Test Report (MTR) & Heat Number
Step-by-step guide to locating and matching heat numbers on physical material and MTR documents.
https://www.meritbrass.com/blog/how-to-read-a-material-test-report
- Mill Steel – How to Read and Interpret Mill Test Reports
Systematic MTR review guide covering chemical composition, mechanical properties, and dimension verification.
https://www.millsteel.com/blog/blog-how-to-read-mill-test-reports
- Evident Scientific – Mill Test Reports in Metal Manufacturing: A Comprehensive Guide
Covers the “trust but verify” principle and the role of PMI testing alongside MTR documentation.
- Holland Applied Technologies – EN 10204 3.1 vs 3.2 Inspection Certificates
Clear comparison of all four EN 10204 certificate types (2.1, 2.2, 3.1, 3.2) with definitions and use cases.
https://hollandapt.com/what-is-the-difference-between-en-10204-3-1-and-3-2-inspection-certificates/
- NTIA – EN 10204 3.1 vs 3.2 Free Certificate Checklist (PDF Guide)
Downloadable checklist for verifying genuine 3.1 and 3.2 certificates, including stamp and signatory requirements.
