An A105 part installed instead of an F11 on a high-temperature line. A "316L" flange that is actually 304. A batch of bars relabelled by a service centre. Metal material traceability is not a bureaucratic requirement: it is the chain that connects the physical part to its heat, its tests and its certificate. When the chain breaks — mixed material, counterfeit certificates, picking errors — the consequences range from non-conformity to recalls, up to in-service failure. This guide explains what EN 10204 documentation really guarantees, where physical verification (PMI) is needed and how to build an incoming material inspection process that stands up to an audit.
What material traceability is and why it is critical
Traceability means being able to trace, for every part or batch: heat of origin, chemical composition, mechanical properties, treatments, tests performed and associated documents. It is an explicit requirement of quality systems: ISO 9001 (clause 8.5.2, identification and traceability) requires identifying the status of outputs and retaining documented information where traceability is required. In regulated sectors (pressure equipment, oil & gas, aerospace, pharmaceutical) traceability is a condition for product acceptance.
The problem is that document-based traceability is fragile by construction: every cut, relabelling, warehouse transfer or change of hands is a point where the paper-part match can break. And the market also knows the worst case: falsified certificates, or genuine ones "recycled" onto material of different origin.
EN 10204: what the certificates really guarantee
The EN 10204 standard ("Metallic products — Types of inspection documents") defines the four documents that accompany deliveries of metallic products. Understanding who signs, and on which tests, is the basis of any documentary risk assessment:
| Document | Tests reported | Who validates | What it really guarantees |
|---|---|---|---|
| 2.1 — Declaration of compliance with the order | No test results | Manufacturer | Only the manufacturer's commitment: no verifiable data |
| 2.2 — Test report | Results of non-specific tests (not necessarily on the delivered batch) | Manufacturer | Typical production data, not data on the delivered lot |
| 3.1 — Inspection certificate 3.1 | Specific tests on the delivered batch/heat (chemical analysis, mechanical tests) | Manufacturer's representative independent of production | The batch was tested and the results are documented; validation remains internal to the manufacturer |
| 3.2 — Inspection certificate 3.2 | Specific tests on the delivered batch/heat | Manufacturer + purchaser's representative or third-party inspector | Double independent validation: the highest level, for critical components |
Practical note: the "3.1" is the standard requirement for structural and pressure materials; the "3.2" is requested where the consequences of a mix-up are unacceptable (critical oil & gas lines, high-category PED, shipbuilding). But even the best certificate has a structural limit: it certifies the heat, not the part in your hands.
Where paper is not enough: PMI as physical verification
PMI (Positive Material Identification) closes the gap between document and part: it is the physical, non-destructive verification that the delivered material has the declared composition. The most mature public reference is the recommended practice API RP 578 ("Material Verification Program for New and Existing Assets"), born in refining after failures caused by alloy mix-ups and today adopted as a model well beyond oil & gas. On the methods side, the ASTM E1476 guide frames metals identification, grade verification and sorting.
The operational tools are two, and complementary:
- Handheld XRF: identifies the alloy in seconds by measuring its characteristic elements (Cr, Ni, Mo, Ti, Nb, Cu...), with no preparation and without damaging the part. It is the standard tool of material acceptance. Physical limit: it does not measure carbon or light elements: it cannot separate 304/304L or 316/316L, nor carbon-steel grades.
- Handheld LIBS: measures carbon via optical emission spectroscopy on a micro-plasma, separating L grades and supporting PMI on carbon and low-alloy steels. It requires minimal surface preparation and leaves a micro-mark.
For instrument selection criteria, see the dedicated guides: how to choose a portable XRF analyzer and LIBS vs XRF for carbon and L grades.
Building the incoming inspection process
A traceability solution for metal parts is not an instrument: it is a process with four key decisions.
- Extent of examination — sampling or 100%: the correct approach is risk-based, as set out in API RP 578: service criticality (pressure, temperature, fluid), consequences of an alloy mix-up, reliability of the supply chain. Beware the statistical limit: on a potentially mixed lot, sampling does not protect you, because the wrong part may be precisely the one not tested. For alloy materials in critical service the practice is 100%.
- Control points: the three typical gates are acceptance (delivery note, certificate, incoming PMI), pre-welding/pre-machining (verification of base and filler materials before added value makes scrap very expensive) and pre-shipment or positive release (the last filter before the customer). Add warehouse checks after every relocation of loose lots.
- Marking and identification: every verified part must be marked or labelled with an identifier linking it to heat and certificate (low-stress marking, resistant labels, lot codes). A PMI without marking is lost at the first transfer.
- Data management: modern analyzers record spectrum, composition, identified grade, date, operator and part ID, and export to the quality system. Instrumental recording is what turns a measurement into audit evidence: measurement → part → heat → certificate.
Sectors and references
- Oil & gas and refining: API RP 578 is the reference for the material verification program: PMI on new supplies, on existing assets and after maintenance, with risk-based extent.
- Pressure equipment and power: 3.1/3.2 certificates on pressure materials and PMI on alloy components (Cr-Mo, stainless, nickel) where a grade mix-up compromises creep or corrosion resistance.
- Aerospace: full batch and heat traceability along the supply chain, with verification of titanium, nickel and aluminium alloys also from an anti-counterfeiting perspective.
- Pharmaceutical and food: the typical request is confirming 316L on process surfaces: here the L grade is the requirement, and without LIBS (or laboratory analysis) the "L" cannot be verified in the field.
Common mistakes
- treating a 3.1 certificate as a guarantee on the physical part rather than on the heat;
- sampling lots that may be mixed, instead of testing them 100%;
- verifying the base material and ignoring welding filler materials;
- doing PMI without marking and without records: the measurement never becomes evidence;
- using only XRF where the requirement is carbon or the L grade;
- not qualifying operators and procedures: PMI is a process, not a "trigger pull";
- forgetting spare parts and maintenance materials, which enter the plant outside the acceptance flow.
PITECH supports the construction of traceability and PMI solutions with complementary instruments: Elvatech handheld XRF analyzers for alloy identification at acceptance and LANScientific LIBS and XRF analyzers where carbon must be measured and L grades separated. The starting point is the XRF/PMI material analysis page: the alloys to verify, volumes, control points and documentary requirements define the right instrument, not the other way round.
Frequently asked questions about material traceability and PMI
What does an EN 10204 3.1 certificate guarantee?
A 3.1 is an inspection document issued by the manufacturer declaring compliance with the order and reporting real test results (heat chemical composition, mechanical properties), validated by a manufacturer's representative independent of production. It guarantees that that batch/heat was tested: it does not by itself guarantee that the delivered part really comes from that heat, nor does it protect against downstream mix-ups or counterfeit certificates.
What is the difference between a 3.1 and a 3.2 certificate?
Both report specific tests on the delivered batch. In a 3.1 the validation is internal: a manufacturer's representative independent of production signs. In a 3.2 the validation is double: a purchaser's representative or a third-party inspector also signs. The 3.2 is typically required for critical components in oil & gas, pressure equipment and shipbuilding.
Is the certificate enough to guarantee the delivered material is correct?
No. The certificate attests to the tests on the heat, but the paper-part match can break at every step: service centres that cut and relabel, mixed lots, picking errors, falsified certificates. That is why material verification programs such as API RP 578 combine document control with PMI: physical verification of composition with XRF and LIBS.
XRF or LIBS for incoming material inspection?
They are complementary. Handheld XRF identifies the alloy and its main elements in seconds with no preparation: it is the acceptance standard. But it cannot measure carbon: it cannot separate 304/304L or 316/316L. Where the L grade or carbon content is a requirement (welds, intergranular corrosion, carbon steels), LIBS is needed, measuring carbon via plasma optical emission spectroscopy.
Do you have to test 100% of incoming materials?
It depends on risk: the API RP 578 approach defines the extent of examination by service criticality, consequences of an alloy mix-up and supply-chain reliability. For critical alloy components many operators require 100%; for low-risk supplies sampling is used. On a potentially mixed lot, however, sampling does not protect you: the wrong part may be precisely the one not tested.