Fabrication, Applications and Quality Management
This module tests the document chain that takes a design into a compliant weld, and the quality system that keeps it compliant in production.
The qualification chain
- Preliminary WPS (pWPS) prepared by welding coordination personnel.
- Welding procedure test to ISO 15614-1 producing a WPQR - the evidence that the procedure works.
- WPS issued to ISO 15609-1, derived from the WPQR within its qualified ranges.
- Welder performance qualification to ISO 9606-1, which is separate from procedure qualification.
- Production welding monitored against the WPS parameters.
Quality framework
- ISO 3834 parts 2, 3 and 4 set quality requirements for welding: part 2 full, part 3 standard, part 4 elementary.
- EN 1090-2 execution classes EXC1 to EXC4 raise inspection and documentation demands with consequence of failure.
- ISO 14731 defines welding coordination tasks; the IWS typically works under an IWE as welding coordinator.
Consumable and distortion control
Bake low-hydrogen electrodes as specified, hold them in a holding oven, and issue only what a shift needs. Control distortion through preset, balanced welding, backstep and correct sequence.
Worked example: qualified thickness range
A WPQR is made on a 10 mm butt test piece in the as-welded condition. Under ISO 15614-1, a test piece between 3 mm and 20 mm qualifies a thickness range from 3 mm up to 2t, i.e. 3 mm to 20 mm. A 25 mm production joint is outside that range and needs a new procedure test - the WPS cannot simply be extended.
Traps
- Believing a qualified WPS also qualifies the welder.
- Extending a WPQR beyond its thickness, position or consumable range without a new test.
- Treating ISO 3834 certification as a substitute for the WPQR chain; it is a management system requirement, not procedure evidence.