Welding is a process whose result cannot be fully verified by looking at it. That is why the industry surrounds it with paper: a procedure specifying how the joint is to be made, a qualification record proving that procedure once produced acceptable properties, and a qualification for each welder showing they can follow it. In a weld dispute this documentation is examined twice — first for whether it exists and is internally coherent, and then against the joint itself, which keeps a physical record of what actually happened at the arc.
Three documents, three different questions
The welding procedure specification, or WPS, is the instruction: joint design, process, filler metal, electrical parameters, position, preheat and interpass temperature, post-weld heat treatment. The procedure qualification record, or PQR, is the evidence behind it — the variables actually used on a test coupon and the mechanical test results obtained from it. The welder or operator qualification record shows that a named individual, tested against the procedure, produced an acceptable weld.
ASME Section IX sets out this framework for pressure work. AWS D1.1 does the same for structural steel, with the additional route of prequalified joints: within defined limits of process, material group, joint geometry and consumable, a procedure may be used without a qualification test, provided every one of those limits is respected.
Essential variables and the limits of a qualification
A qualification is not general permission to weld. It is valid over ranges of thickness, diameter, position and material grouping, and it is invalidated by changes to what the code designates as essential variables — a change of process, a change of filler metal classification, or a reduction in preheat below what was qualified. A common finding in a documentation review is not a missing procedure but a procedure being used outside the range its qualification record actually supports.
Preheat and interpass temperature as a record
Preheat and interpass control governs cooling rate and gives diffusible hydrogen time to leave the joint, and it is among the requirements most likely to slip under production pressure on a cold site. It is also the requirement whose records are thinnest, often a signature on a traveller rather than a measurement.
The joint itself is the check. Hardness across the heat-affected zone and the microstructure at the fusion boundary reflect the cooling rate the steel actually experienced. Where the metallurgy and the paperwork disagree, the metallurgy is the more direct evidence of the two.
Consumables, storage and moisture
Low-hydrogen electrodes and fluxes absorb moisture from the air, and moisture is a hydrogen source. The controls are unglamorous: sealed packaging, holding ovens at specified temperatures, limited atmospheric exposure time, and rebaking or discard once that exposure is exceeded.
A manufacturer's certificate for a consumable establishes what was made, not what condition it was in at the arc. Purchase records, oven charts, issue logs and the storage arrangements on site are what speak to condition, and their absence is itself a finding.
The welder is a separate question from the procedure
Welder qualification carries its own range limits and its own continuity requirements: a qualification lapses where the process has not been used within a stated period, and requalification or documented continuity is then required. Establishing who welded which joint, when, under what qualification, and whether that qualification was current and covered the position and thickness in question is ordinary record work, and it is frequently decisive.
Reading the paper against the metal
The joint can be interrogated directly. Chemical analysis of the deposit indicates whether the filler metal used corresponds to the classification the procedure specified. A macroetch section shows bead count, bead placement and sequence, penetration and joint preparation angle, each of which can be compared against the procedure's joint detail.
Hardness traverses speak to preheat and heat input, microstructure at the fusion boundary speaks to cooling rate, and an excavation with a second thermal cycle over it speaks to a repair that may or may not appear in the log. A procedure that was followed and a procedure that was merely filed look identical on paper and different under an etchant.
Post-weld heat treatment and its charts
Where the construction code or the material requires post-weld heat treatment, the evidence is a time-temperature chart with identifiable thermocouple traces, holding temperature, hold time, and controlled heating and cooling rates. Charts that cannot be tied to the specific component, or treatment carried out before rather than after a repair, are recurring issues. Hardness and microstructure again indicate whether the component saw the treatment the record claims for it.
The records worth requesting early
Beyond the procedure, qualification record and welder credentials: material test reports and heat traceability for plate and consumables, weld maps or joint travellers linking each joint to a welder and a procedure, preheat and interpass logs, examination reports and repair records, post-weld heat treatment charts, and the fabricator's own quality manual and inspection plan. Retention periods vary, and they are often shorter than the timeline of the dispute itself.
Where a documentary case is attacked
Predictably: that the reviewer applied a code edition other than the one in the contract, that a variable treated as essential was not essential under that edition, that the range limits were read too narrowly, and that a paperwork non-conformity was presented as though it explained a failure it may have had nothing to do with. Documentation findings hold up best when each is tied back to a physical observation in the joint, or expressly identified as a compliance question rather than a causal one.
This article is general technical orientation, not a failure analysis, an engineering opinion, or advice on any specific matter. Determining the cause of a particular incident requires hands-on examination by a credentialed expert.