How many WPSs can one WPQ qualify a welder to follow?

Per AWS D1.1 Clause 6 position tables, a single WPQ can qualify a welder for multiple WPSs as long as the WPS essentials (process, position, thickness, progression) fall inside the WPQ's qualified range.

If my welder qualifies on 1-inch plate, can they weld 1/4-inch plate?

Typically yes. Most WPQs qualify down to a fraction of the test thickness (often 1/8 in minimum) and up to 2x the test thickness, per Clause 6 position/thickness tables. Always check the specific table for your test position.

What's the 6-month continuity rule?

AWS D1.1 Clause 6 requires that a welder continue using a qualified process at least once every 6 months to maintain qualification. After 6 months without using a process, the welder must requalify in that process.

Welder qualification (WPQ) traceability to the WPS

A WPS authorizes a procedure. A WPQ authorizes a welder. The link between them is the most-audited connection in welding QC.

A WPS authorizes a procedure. A WPQ (Welder Performance Qualification) authorizes a welder to follow it. The link between the two is the most-audited connection in welding QC. Auditors walk the production floor, identify a weld, and trace it both upward to a WPS and sideways to the welder's WPQ. Any break in either trace is a finding.

What a WPQ contains

A complete AWS D1.1 WPQ records:

Welder's name, employee ID, and stamp number
Date of qualification test
WPS used for the test (or the qualifying parameters)
Process(es) tested
Position(s) tested
Thickness range qualified (derived from test thickness)
Diameter range qualified (for pipe)
Test results — typically visual + bend tests per Clause 6
Witnessing inspector's name, credential, and signature
Continuity record start date

A WPQ is signed by the witnessing CWI or inspector.

Position tables — what a WPQ actually qualifies

AWS D1.1 Clause 6 includes position tables that map test positions to qualified production positions. A few common rules:

1G test (flat groove) qualifies 1G and 1F production only
2G test (horizontal groove) qualifies 2G + 1G + 1F + 2F
3G test (vertical groove) qualifies 3G + 2G + 1G + 1F + 2F + 3F
3G + 4G tests together qualify all positions (3G + 4G = full position qualification)
6G test (45° fixed pipe) qualifies all positions for both pipe and plate

The full position picture comes from 3G + 4G or 6G. Most production shops have welders qualified to one of those two combinations.

Thickness range

Test thickness sets the qualified production thickness range:

Test on 3/8 in → qualified for 1/8 in to 3/4 in production (roughly)
Test on 1 in → qualified for 1/8 in to unlimited
Test on pipe at 6 in NPS schedule 80 → qualified for that diameter and most smaller diameters

The exact qualified range comes from Clause 6 thickness tables. A rule engine that knows the tables can output "Welder X is qualified for WPS Y" or "not qualified" deterministically.

Continuity — the 6-month rule

Once qualified, a welder maintains qualification by using the process at least once every 6 months. Documentation requirements:

Continuity log shows welder's name, process, and date of last production weld
Foreman or QC clerk updates after each production cycle
If a welder lapses on a process, their WPQ for that process is suspended until requalification

The continuity log is a common audit finding. Shops with a paper log update it sporadically; the auditor walks in mid-month and the log is 6 weeks out of date.

How to enforce traceability

Three approaches:

1. Paper assignment slips. Each weld assignment has a slip listing the WPS, the welder, the welder's WPQ. Inspector verifies before welding starts.

2. Stamped weld map. The weld map shows weld locations; each weld is stamped with the welder's stamp number. WPS reference is on the drawing.

3. Digital welder-to-WPS matching. Software cross-references welder WPQs to authorized WPSs and prevents assigning a welder to a procedure they can't qualify under. Foolproof, but requires investment.

Common traceability findings

Production weld with no clear WPS reference on the drawing or weld map.
Welder stamp present but the welder's WPQ doesn't cover this process or position.
WPQ continuity gap > 6 months. Welder produced welds while not qualified.
WPS revision changed; welder's WPQ tested against prior revision. Usually OK if essential variables didn't change, but should be documented.
Welder stamp on welds, but the welder is no longer with the company and the stamp wasn't retired. Stamps must be retired when welders leave.

The audit-day trace

For each randomly selected weld:

What WPS authorizes this weld?
Is the WPS current? (cross-check the library)
Who welded this? (stamp on the weld)
Does the welder hold a current WPQ for this WPS's process, position, and thickness?
Is the welder within the 6-month continuity window for this process?

All five must trace cleanly. Any one break is a finding.

A WPS tool that maintains welder-WPS authorization mappings — and refuses to assign work that can't trace — eliminates this entire failure mode.