Qualification testing of welders — fusion welding — part 1: steels

What a certificate actually covers

A welder’s certificate is not a licence to weld. It is a statement that the welder demonstrated competence within a specific range, and the range is defined by essential variables: welding process, product type, type of weld, parent material group, filler metal, dimensions, welding position, and weld detail.

Every one of those carries its own rule for how far the qualification extends beyond what was tested. Thickness and diameter ranges in particular are arithmetic — which means they can be computed rather than remembered, and computing them is how you stop assigning a welder to a joint they do not cover.

The designation string

The certificate carries a designation that encodes the qualified variables in a defined order. It is dense and it is exact, and it is written by hand more often than it should be. Built from the qualified variables instead, it cannot disagree with the certificate it appears on.

Validity and continuity

The qualification is valid for a defined period on condition that continuity is confirmed at six-month intervals by the person responsible for welding coordination. Prolongation at the end of the period is possible when the required production evidence exists — test reports for welds made in the last months of validity, traceable to the welder, made under procedures consistent with the qualified ranges.

Miss the evidence and the route is requalification with a new test piece. The cost of that is not the test; it is the welder who cannot be assigned to work in the meantime.

Where this bites

The confirmation is a signature every six months. It is exactly the kind of obligation that is easy to satisfy and easy to forget, and the discovery usually happens when a certificate is produced for a client audit — long after the window has closed.