Welder Performance Qualification (WPQ1)
What this domain tests
Welder performance qualification proves that an individual can produce sound welds to a qualified procedure. Keep the two ideas firmly apart: the WPS/WPQR proves the procedure is sound; the WPQ proves the person can apply it. A common written question simply swaps these.
Essential variables for a welder
Process, position, joint type and backing, current type and polarity, filler classification, transfer mode (GMAW short-circuit vs spray vs pulsed; FCAW), direction of welding (vertical up vs down), test-piece thickness and pipe diameter. Welders and welding operators (machine/automatic) are usually qualified under different clauses with different ranges.
Test piece and range of qualification
A test assembly is welded, then examined: visual first, then radiographic/ultrasonic testing or bend and macro tests, as the applicable standard requires. The coupon converts into a production range. The familiar rule of thumb is that a coupon of thickness t qualifies from a defined minimum up to roughly 2t; single-pass deposits qualify a much narrower band than multi-pass work. Position coverage is asymmetric: under ASME IX a 6G pipe test qualifies all positions plus both plate and pipe, whereas a plate test never qualifies pipe. Small-diameter pipe limits the diameters qualified.
Continuity
The qualification is not permanent. It lapses after a defined period of inactivity and needs periodic employer/Examiner confirmation, commonly every six months. Responsibility sits with the employer and does not follow the welder to a new company.
Worked example: a welder deposits a multi-pass groove on 150 mm (6 in.) pipe in the 6G position, GTAW root plus SMAW fill/cap. Result: all positions, plate and pipe. Thickness is assessed per process, from each process's deposited thickness, not from the coupon thickness.
Traps: assuming one thin coupon covers heavy plate; assuming a qualified WPS qualifies the welder; assuming a WPQ transfers between employers.