Welding Inspection and Quality Assurance
Scope of inspection and QA
Welding inspection verifies that fabrication follows the approved design, code, and contract. Quality assurance (QA) is the planned system that prevents nonconformance; quality control (QC) is the inspection and testing that detects it. Candidates must know the inspection and test plan (ITP), hold points, witness points, surveillance, and document review. A hold point stops work until the authorized inspector signs release. A witness point requires notification but normally does not stop work if the inspector is absent, unless the contract says otherwise.
Inspection begins before welding: verify WPS availability, welder qualification, consumable storage and baking, joint preparation, fit-up, preheat, and calibration of measuring and NDE equipment. During welding, monitor process variables, interpass temperature, cleaning, and root condition. After welding, verify dimensions, profile, NDE completion, PWHT records, and traceability.
Traps
- Confusing QA with QC, or treating a witness point as a hold point.
- Assuming inspection transfers quality responsibility away from the fabricator.
- Accepting a procedure or welder without checking qualification scope.
- Missing calibration status or consumable control records.
- Applying project acceptance criteria when the code or contract specifies a different criterion.
Worked rule
If an ITP lists 'hold' at fit-up, the inspector must document acceptance before welding. If the item is 'witness,' notify the inspector; absent a contractual stop, work may proceed. Always read the contract definition, because some owners upgrade witness points to hold points.