Welding Quality Assurance: Principles, Documentation and Acceptance
What QA actually means
Quality assurance is the planned system that makes quality predictable before a weld is made: qualified procedures, qualified personnel, controlled consumables, traceable records and defined acceptance criteria. Quality control, by contrast, is the inspection act itself. Questions often conflate the two; if an option describes measuring or testing, it is control, not assurance.
Core concepts to master
Know the document hierarchy. A welding procedure specification (WPS) states how a joint is to be made; it must be supported by a procedure qualification record (PQR) demonstrating that a test piece made to that procedure passed the required mechanical tests. Personnel are qualified separately by a welder qualification test. A critical trap: a WPS cannot be qualified by a welder's qualification test, and a PQR is a historical record that is not edited to suit later production. Also understand essential variables (for example, change of base metal group, filler classification, joint type, or significant thickness change) - changing one normally requires requalification unless the relevant standard permits an exemption.
Consumables control is a frequent topic: storage, drying of electrodes, holding ovens, issue and return records, and traceability to the weld. Records should allow a weld to be traced back to procedure, welder, consumable batch and inspection results.
Worked example
A fabricator's WPS lists a 12 mm thickness range. Production requires 20 mm. The correct answer is not "weld it and inspect heavily" but "check whether the standard allows a thickness extension; if not, requalify the procedure and issue a revised WPS." Rule of thumb: if it appears in the essential variables list, treat any change as a requalification trigger until proven otherwise.
Traps
Watch for options that rely on more inspection to compensate for an unqualified procedure, or that treat a PQR as a variable document.