Joint geometry · Clause 5 and Clause 6

What must a plug or slot weld WPS identify?

Start with the design drawing and identify which member contains the hole or slot, the connected member, the required size and fill depth, the weld position, and the production sequence. These are plug/slot welds; a fillet weld placed around an opening is a different weld detail.

Working rule: The design defines the required connection. The WPS records how an approved detail will be made and which qualification route supports it. A welder plug test, a fillet qualification, and a plug/slot procedure qualification are distinct evidence paths.

Collect the drawing and procedure inputs

Input	What to capture	Why it matters
Members and materials	Member labels, thicknesses T1/T2, specifications and grades, product form, coating or surface condition, and which member is perforated	Separates design geometry from the qualification coverage and preparation method.
Hole or slot	Shape, diameter d or width and length, end radius, edge distances, spacing, number and pattern	Dimensions and spacing are design-controlled; they cannot be inferred from a weld symbol alone.
Required weld	Plug or slot designation, fill depth t, flush/partial-fill condition, and any specified contour or inspection requirement	Separates weld metal in the opening from a perimeter fillet and clarifies the production target.
Production method	Process, position, progression if relevant, consumable and size, backing/support if applicable, pass sequence, and cleaning between layers	Supports a complete procedure and a check against the chosen Clause 5 detail or PQR qualification.
Project constraints	Contract code edition, static/cyclic service requirements as stated by design, inspection hold points, and approved repair/design instructions	WPS preparation does not set structural size, acceptance criteria, or inspection scope.

Geometry checks before writing the WPS

AWS D1.1/D1.1M:2025 Clause 4.5.5 and 4.11 govern the plug/slot design geometry referenced by the prequalified joint-detail provisions. For a preliminary drawing check, 4.5.5.1 sets the minimum hole diameter or slot width as the perforated-member thickness T plus 8 mm [5/16 in]. The maximum is the greater of that minimum plus 3 mm [1/8 in] or 2.25T. Slot length is limited to 10T; a slot end is semicircular or has a corner radius at least T. Plug center spacing is at least four hole diameters. For slots, transverse row spacing is at least four slot widths and longitudinal spacing at least twice slot length. Use the contract’s unit system and the actual code notes.

Fill depth is a separate dimension from member thickness: for T up to 16 mm [5/8 in], fill depth is T; for thicker perforated members, it is at least the greater of T/2 or 16 mm [5/8 in], without requiring fill beyond the thinner connected member. Confirm the exact detail and all applicable exceptions in the controlled code text before finalizing a job.

These are drawing checks, not a structural design. Do not resize holes, change spacing, or select a different effective weld from the WPS. Clause 4.11.4 prohibits plug/slot welds in Q&T steel with specified minimum yield strength greater than 70 ksi [490 MPa]; that prohibition must be respected; a PQR does not cancel a production design prohibition.

Separate the two procedure routes

Route	Evidence to establish	Procedure boundary
Clause 5 prequalified WPS	Applicable prequalified plug/slot joint detail, all geometry and material conditions, permitted process/position, consumable and process limits, and required procedure fields	Use the selected code detail and its notes. A drawing outside its conditions does not become prequalified because the weld looks similar.
Clause 6 WPS from an existing PQR	Original readable PQR and reports; test type and position; actual geometry, materials, thicknesses, process and variables; applicable Tables 6.1 and 6.5 and Clauses 6.11–6.14	Apply the plug/slot branch specifically. Table 6.5 has specimen ranges and associated geometry/fill-depth boundaries; the exact tested position matters. Do not borrow a groove-weld thickness formula.

A fillet test can qualify certain production plug/slot welds under the distinct provisions in Clause 6.13.1 and the corresponding Table 6.1 positions. This is not the same route as direct plug testing under 6.14 and Table 6.5. Record which route is used, then apply its own limits.

Bounded example: a slot wider than a tested plug hole

Suppose the only record is a plug test. Clause 6.14 says the tested position qualifies plug/slot welds, with the slot-width condition tied to the tested hole diameter; Table 6.5 then supplies the specimen and production ranges. A wider proposed slot cannot be accepted by treating “plug/slot” as one unrestricted category. First establish whether the exact Table 6.5 route and geometry support it. If not, identify another applicable qualification path or mark the evidence gap; do not increase the range by inference.

Keep design decisions and WPS facts separate

Preserve the drawing number and revision, weld symbol, member labels and every given dimension.
Ask the responsible design authority for a missing or conflicting hole size, slot length, pitch, fill depth or acceptance instruction.
Put only approved design dimensions and supported process conditions into the production WPS.
Record the PQR ID, test report, tested position, test type, code edition, and table/paragraph path used for qualification.
Do not convert personnel qualification, workmanship inspection, or a passed production weld into WPS qualification evidence.

Product scope is preparation of a WPS from a complete prequalified detail or applicable existing PQR. Structural sizing, new qualification tests, defect disposition and final acceptance remain with the project’s designated responsible parties.

Code basis and related guides

Basis: AWS D1.1/D1.1M:2025 base edition plus the registered July 28, 2026 base-edition errata; AMD1 is not included. The governing contract edition controls each project. Confirm all applicable table notes and project requirements against the controlled code text.

Fillet weld details and fit-up Map actual PQR values PQR test positions Edition and errata basis

Need a WPS prepared from defined project inputs?

Provide the drawing, applicable procedure or PQR, and the records that establish the requested production conditions.

Start a WPS request

Continue this WPS review

Keep the design-controlled hole or slot geometry with its procedure support.

Fillet detail comparison
Distinguish a perimeter fillet from a plug or slot.
Drawing-to-WPS inputs
Collect dimensions, fill depth and position.
PQR coverage review
Use the applicable test-type branch.
Prequalified WPS preparation · $299
For a complete procedure meeting all applicable Clause 5 conditions.
Existing-PQR WPS preparation · $499
For a procedure fully supported by applicable existing records; no new qualification testing.