A material test certificate, or MTC, is a document that reports the chemical composition and mechanical properties of the metal in your parts. EN 10204 type 3.1 is the most commonly requested level: it states that the results come from tests on the delivered product and are validated by an inspection representative independent of the manufacturing department.
For castings and forgings, the MTC is your main written proof that the part is the grade on the drawing. It is only as good as the testing behind it, so you need to know how to read one.
The EN 10204 document types
EN 10204 defines four types of inspection document. The current edition dates from 2004 and is widely used outside Europe as well.
- Type 2.1 is a declaration of compliance with the order, with no test results.
- Type 2.2 is a declaration of compliance with results from non-specific inspection, meaning typical results from the producer's routine testing, not from your batch.
- Type 3.1 gives results from specific inspection of the delivered product, validated by the manufacturer's authorised inspection representative who is independent of manufacturing.
- Type 3.2 is like 3.1 but is also validated by your own inspector or an inspector named in official regulations, so a third party has witnessed or verified the tests.
What a 3.1 certificate for a casting should show
- The foundry's name and address, the certificate number and the EN 10204 type.
- Your order number, the part number and the drawing revision.
- The material standard and grade, for example EN-GJS-500-7 to EN 1563.
- The heat or melt number, which should also be marked or traceable on the parts.
- The chemical analysis for the heat, with the specified limits beside the results.
- Tensile strength, yield strength and elongation from the test bar, and the type of test bar used.
- Hardness results, and for SG iron, nodularity and microstructure if your order asks for them.
- Heat treatment details, if the part was heat treated.
- The name and signature of the authorised inspection representative and the date.
How to check one
Read the certificate against your drawing, line by line. The grade must match exactly, and each result must sit inside the limits. A certificate that lists limits different from the standard is a warning sign.
Then check traceability. The heat number on the certificate should match the marking on the parts or the packing list. If the foundry cannot link the two, the certificate proves little about what is in the box.
Ask whether the tests were done in-house or at an outside laboratory, and whether that laboratory is accredited for the tests. The general approach in reading a lab certificate applies here too.
When to ask for 3.2
For pressure parts, safety-critical components or orders under a project specification, you may need 3.2. This adds a third-party inspector, which takes planning, because the inspector must witness tests or review records at the foundry. Arrange it before production starts, not at loading. See what a third-party inspection certificate is for how this is usually organised.
Your end customer's specification or the applicable pressure code decides which type is required. Confirm the requirement with them before you order.
Next step
We check MTCs against drawings, trace heat numbers to the parts, and can have lots tested independently. To set this up for your castings, book a free sourcing review.