Why material certificates matter in contract manufacturing

When a supplier builds to your drawing, the steel plate, bar, forging or casting needs a traceable record. A material certificate links the delivered component to the chemical analysis, mechanical properties and heat identity recorded for the batch. If that link is missing, the buyer cannot verify the drawing requirement or trace a later material problem to its source.

This matters most for structural, pressure-containing and safety-related equipment. A broken record can allow the wrong grade to pass through fabrication without being noticed. The mismatch may only appear when the buyer compares the final documents with the parts, by which point replacement or rework is costly.

EN 10204 certificate types and what each proves

The current BSI listing for EN 10204:2004 identifies it as the European standard for metallic-product inspection documents. The standard uses four document types. The practical distinction for an RFQ is whether the document contains no test results, results from non-specific inspection, or results from specific inspection of the delivered material:

  • Type 2.1 is a declaration of compliance with the order. No test results are included.
  • Type 2.2 is a test report based on non-specific inspection, meaning results from the same process route rather than your exact batch.
  • Type 3.1 is an inspection certificate with results from specific inspection, issued by the manufacturer's authorized representative who is independent of the production department.
  • Type 3.2 adds a second signature from the purchaser's representative or an independent third-party inspector.

The international counterpart, ISO 10474:2013, also defines inspection documents supplied with steel products according to the order. Do not assume that one certificate type is suitable for every component. The drawing authority or applicable code should set the required document, and the RFQ should repeat that requirement without changing it.

Heat number traceability and the mill test report

Traceability depends on the heat number or other batch identifier assigned by the material producer. That identifier must remain connected to the material certificate and to the physical stock or part through an agreed marking and transfer method. If the link is broken during cutting, machining or fabrication, the certificate alone does not prove which material went into the finished component.

A mill test certificate or report records the information required by the ordered document type. Depending on the product and standard, that can include the batch identity, dimensions, delivery condition, chemical composition and mechanical test results. When reviewing it, confirm that the identifier follows the agreed traceability route, the grade and standard match the drawing, and any reported test results apply to the material represented by the document.

What to write into the RFQ

A useful certificate requirement in a contract manufacturing RFQ states the minimum certificate type, the standards the material must meet, and the traceability the supplier must maintain. Consider specifying:

  • the material standard and grade, with the edition or year where the design depends on it;
  • the EN 10204 document type required by the design authority or governing code, including any purchaser or third-party validation;
  • heat number marking on the delivered parts and on the certificate;
  • the mill test report delivered with the parts, not after payment;
  • any project-specific additions such as impact testing, positive material identification, or a restriction on substitute heats.

State who arranges and pays for third-party inspection. If the RFQ leaves that responsibility open, bidders may price different scopes and the gap usually appears late.

Also define the document language, file format and submission timing if those details affect the buyer's review process.

Where responsibility sits

Responsibility is split across the project. The design authority sets the grade and acceptance specification. The buyer carries the required certificate type and traceability level into the purchase order. The supplier procures the specified material, preserves the link between the batch and its documents, and delivers records that match the supplied parts.

A contract manufacturer should not be expected to invent a grade the drawing does not state, and it cannot accept a substitute heat without the buyer's or designer's confirmation. Where the part is welded, material traceability connects to welding quality records, so the certificate requirement should be stated alongside the welding specification rather than as a separate afterthought.

How Realjet handles documentation

For a made-to-drawing enquiry, Realjet needs the material standard, grade, required certificate type and any project-specific traceability rules before it can define the documentation scope. Those inputs allow the quotation and technical review to address procurement, identification transfer, fabrication records and the final document package without assuming requirements that are absent from the drawing.

Send the controlled drawing, the material specification, the required EN 10204 type and any project acceptance standard through the contract manufacturing enquiry route so the quotation can address the correct documentation and traceability scope for your parts.