The certification of welds and welders is a requirement of several application standards and a critical part of the quality management of all projects were welds are used. The quality of a weld can not only be determined by a quality control (non destructive inspection) at the end.
To guarantee the quality of a weld the application standards regulate the level of traceability/management for all steps in the production process. Starting from design, material certificates, weld and welder certificates, … NDT till the final approval and CE and DOP documents.
The certification of procedures and personnel are a key part in this process.
A weld qualification will demonstrate the capability of a certain weld “recipe” (pWPS: preliminary weld procedure specification) to comply with the requirements of the applicable standards. The “recipe” will describe all necessary parameters to create the weld.
During a weld qualification an independent expert will witness and record all required parameters. After welding the weld is visually examined on site. Then the weld will be Non-destructively (NDT) and destructively tested (DT).
After approval of NDT and DT the weld procedure will be created.
Welder/operator qualifications are required to demonstrate the skill and knowledge of a welder. This is tested on the basis of a weld instruction (pWPS or WPS/LMB). The welder will be evaluated on the basis of understanding/ applying the instruction and on the performed weld quality.
The mechanical/ chemical properties of the finished weld are usually not a part of a welder qualification.
KTN Belgium performs these qualifications onsite, ensuring that the welders can use the same equipment as in production and a direct onsite evaluation of the visual inspections (including fillet weld fracture tests).
