Sample document package
Asking a supplier for a redacted sample document package tells you more than a factory visit. Two things become clear immediately: whether they can produce the documents at all, and whether the documents are legible, complete and internally consistent.
Sample scans pending. Redacted samples from real DERVOS VALVE orders
will be published here. We are not publishing generic or illustrative certificates in the
meantime - a sample certificate that is not from a real order proves nothing.
What the package contains
| Document | What it proves | What to check |
|---|---|---|
| Mill certificate EN 10204 3.1 | Chemistry and mechanical properties for the heat | Check the grade-specific elements - V, Nb and N on F91; W and B on F92 |
| Forging heat treatment chart | Actual furnace trace with thermocouple positions | Not a certificate saying treatment was done - the trace |
| Pre-machining UT report | Volumetric examination of the forging | Cannot be produced retrospectively. The most informative document to ask for |
| PWHT chart | Per pressure-boundary weld | Essential on creep grades |
| Hardness survey after PWHT | Results per location with the acceptance range | The only production check that F91/F92 will perform in service |
| PMI report | Per pressure-containing part | Every part, not a sample |
| Hydrostatic shell test report | Actual pressure, actual duration, observation | With the gauge calibration reference |
| Seat test report | Observed leakage against the allowable rate | Allowable is not zero for metal seats |
| NDE reports | MT / PT on machined and hardfaced surfaces | With operator qualification level |
| Dimensional report | Against the approved GA drawing | Heat numbers should match the MTC |
The five-step consistency check
Do this on receipt, or at inspection. It takes a few minutes per valve.
- Read the heat number stamped on the valve body.
- Find that heat number in the document package.
- Check the chemistry on that certificate against the specified grade.
- Find the PMI report for that part and confirm it agrees.
- Check the heat number also appears on the dimensional report for the same serial number.
If any step fails, the traceability chain has a gap - and a gap means you do not know what the valve is made of. More on the chain.
Sample scans
Request a package
Available on request now by e-mail, from a previous similar item with commercial information removed.