ASME standard · reference card
ASME BPVC Section IX qualifies welding, brazing and fusing procedures and personnel. Scope decision flow, the construction codes that invoke it, and the production records that show a weld stayed inside its qualified variables.
Section IX is a qualification code. It says how to prove that a procedure will produce a sound joint, and how to prove that a person can follow it — and it draws the boundary of that proof with essential variables: change one beyond its stated range and the qualification no longer covers the work.
The practical failure is rarely a bad qualification test. It is a production weld that quietly drifts outside the range the record supports, on a machine whose displays all look normal. Travel speed is the usual culprit because it is the value estimated rather than measured, and arc energy moves inversely with it.
Where impact testing is required by the construction code, that drift becomes a documentation problem as well as a metallurgical one: the supplementary essential variables bring heat input under control, and control implies a record. Recording measured values per pass turns an argument about what probably happened into a file with the answer in it.
| Question | If yes | If no |
|---|---|---|
| Does the construction code for the item invoke Section IX? | Section IX governs the qualifications; the construction code still governs acceptance. | Use the qualification route that code names — commonly the ISO 15614 series in the European scheme. |
| Is the joining process welding, brazing, or plastic fusing? | Use the matching part: welding, brazing and fusing each have their own article. | Section IX does not cover it; go back to the construction code. |
| Does the construction code require impact testing for this item? | Supplementary essential variables come into force alongside the essential ones, and heat input becomes a controlled quantity in production. | Essential and nonessential variables apply as written. |
| Is a published standard welding procedure specification acceptable to the construction code? | It may be adopted without a new qualification test, subject to the demonstration the code requires. | Qualify your own procedure and record the results on a qualification record. |
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 |
|---|---|---|
| Showing production welds stayed inside the ranges the qualification record supports | Measured voltage, current and wire feed speed per pass, against the qualified range | WeldTrace |
| Controlling heat input where supplementary essential variables apply | Arc energy computed from measured values per pass rather than from nominal sheet figures | WeldTrace |
| Holding interpass temperature within the qualified band on multi-pass work | Non-contact interpass measurement on every pass instead of a spot check between passes | HeatCam IR-C |
No. A qualification record proves the procedure can produce sound welds within stated variable ranges. A production weld outside those ranges is outside the qualification even when the finished bead looks correct, which is why measured production values matter.
The electrical and travel-related ones: current, voltage, wire feed speed, and the arc energy derived from them, plus interpass temperature. Joint design, position, material grade and post-weld heat treatment are documented, not measured by the cell.
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.
Progetto cofinanziato nell'ambito del PR Piemonte FSE+ 2021-2027,
Priorità I, Obiettivo Specifico a), Azione 4 – "Sostegno alla nascita delle start up"
