ISO standard · reference card
ISO 3834-2 sets comprehensive quality requirements for fusion welding. Decision flow for choosing between parts 2, 3 and 4, the codes that invoke it, and the records that satisfy its equipment and traceability clauses.
ISO 3834 answers a question no acceptance standard answers: is this manufacturer organised to produce sound welds repeatedly. Parts 2, 3 and 4 are the same subject at three depths — comprehensive, standard and elementary — and the number is not a grade of the welds, it is the extent of the quality requirements the manufacturer has committed to.
Part 2 is the version most often demanded in pressure equipment, rail and marine work because it requires the whole chain: technical review, procedure and personnel qualification, consumable and parent-material control, production planning, equipment suitability and calibration, inspection and testing, non-conformance handling, and the records that evidence all of it.
Two clauses in that list are where monitoring earns its place, and both are worth naming plainly. Inspection and testing wants evidence taken during welding, not only after it; identification and traceability wants each weld tied to who made it, when, and under what conditions. Continuous per-weld records answer both without adding an inspection step to the cell.
| Question | If yes | If no |
|---|---|---|
| Does an application standard or contract already name a part? | Work to the part it names; the choice is made. | Select it from the criteria in ISO 3834-1 with the guidance in ISO 3834-6. |
| Is the product safety-critical, or does it involve a wide material range and demanding metallurgy? | The comprehensive requirements of part 2 are the expected route. | Parts 3 or 4 may be proportionate. Record the reasoning; an auditor will ask for it. |
| Is structural steelwork in scope under EN 1090-2? | The execution class drives the part. EN 1090-2 maps each class to an ISO 3834 part — read the mapping in the copy in force, it is not reproduced here. | Use the ISO 3834-1 criteria directly. |
| Do you weld under subcontract, or subcontract welding out? | The subcontracting clause applies in full, and the responsibility stays with you. | Continue, but re-check whenever a supply chain changes. |
Conformity is decided by inspection and testing against the criteria the standard and the contract set. The records below are evidence that the process was held where it was qualified; they support an inspection result, they never replace one.
| Requirement | Record produced | Source |
|---|---|---|
| Inspection and testing before, during and after welding | Continuous in-process thermal and parameter records per weld, not a sample at the end of the shift | HeatCore AI |
| Identification and traceability of welds, welders and consumable lots | Weld identifier, operator, timestamp and process record joined in one exportable record | WeldTrace |
| Validity of measuring, inspection and testing equipment | Verifiable calibration state and validation records for the monitoring chain itself | HeatCam IR-C |
Of the manufacturer. It demonstrates the capability of the organisation to produce welded construction of a declared class. Individual joints are still accepted against a quality-level standard and the testing extent the contract sets.
Yes. The declaration has a scope — sites, processes, materials and product ranges — and different parts can apply to different scopes. What is not allowed is quoting the higher part for work outside the certified scope.
Therness records what the machine actually delivered on every weld — parameters, thermal signature and a per-weld trail — so a conformity argument rests on measurements instead of recollection.
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