Does a PQR for a CJP groove weld also qualify PJP?

Generally yes — a PQR that qualifies complete joint penetration covers the more demanding condition, so partial joint penetration in the same base metal group and thickness range is typically supported. The reverse is not necessarily true: a PJP PQR does not automatically cover CJP joints.

What is the effective throat for a PJP groove weld?

Effective throat is the minimum distance from the joint root to the weld face, minus any reinforcement. For a PJP, effective throat is determined by the groove geometry and the depth of fusion achieved — and must equal or exceed the design-required throat. AWS D1.1:2025 Clause 5 lists effective throat for each prequalified PJP joint type.

Do PJP groove welds require UT or RT?

Not routinely. AWS D1.1:2025 requires volumetric NDE (UT or RT) for CJP groove welds in statically loaded tension and for all CJP groove welds in dynamically loaded structures. PJP groove welds are typically exempt from volumetric NDE unless the engineer or contract specifies otherwise.

Can I use a prequalified WPS for a CJP joint without a PQR?

Yes, if the joint matches an AWS D1.1:2025 Clause 5 prequalified CJP detail exactly — groove angle, root opening, root face, backing configuration, and base metal all within the prequalified limits. Any deviation from the Clause 5 geometry requires a qualified WPS backed by a PQR.

May 27, 20266 min read

CJP vs PJP groove welds: WPS scope under AWS D1.1:2025

CJP and PJP groove welds differ in qualification scope, NDE requirements, and PQR coverage under AWS D1.1:2025. Here's what every CWI needs to know before first arc.

CJP PJP groove weld AWS D1.1 WPS NDE

New to procedures? Start with WPS welding: what a welding procedure specification is, with a filled-in example.

The weld symbol on a structural drawing calls out a groove weld. What's missing from the symbol — or buried in the general notes — is whether that joint must achieve complete joint penetration (CJP) or can stop at partial joint penetration (PJP). The distinction carries real consequences for WPS selection, qualification testing, and post-weld NDE.

Misapplying a PJP WPS to a joint the structural engineer specified as CJP is a deficiency. The weld may look identical from the outside; the effective throat shortfall is internal and invisible to visual inspection.

What the terms mean structurally

Complete Joint Penetration (CJP) means weld metal fully fuses with the base metal through the entire cross-section of the joint. Effective throat equals the full plate thickness (or connection thickness). CJP is used where the connection must develop the full tensile capacity of the weaker connected element — typical applications include:

Butt-welded column splices
Beam-to-column moment connections (AISC special and ordinary moment frames)
T-joint demand-critical connections in seismic design
Full-strength butt welds on primary load-carrying members

Partial Joint Penetration (PJP) means weld metal fuses only partway through the joint. The structural engineer defines the required effective throat based on the applied load. PJP is used where through-thickness tension is not the design loading, or where the joint geometry makes CJP impractical. Common applications:

Column-to-base-plate groove welds (compression-dominant)
Built-up girder web-to-flange welds where the section carries bending
Box column corner groove welds in axial compression
Skewed connections where access prohibits full penetration

Rule library based on AWS D1.1:2025; verify against your governing edition.

Prequalified joints: Clause 5

AWS D1.1:2025 Clause 5 lists prequalified joint geometries for both CJP and PJP. A WPS built on a Clause 5 prequalified joint is a prequalified WPS — it does not require a PQR as long as all prequalified limits are met (base metal, filler classification, heat input, preheat, position).

CJP prequalified joints in Clause 5 include:

TC-U4a/b: single-bevel T-joint with backing bar or backgouged open root
BC-U2a/b: single-V butt joint with backing or backgouge
TC-U4c: double-bevel T-joint (both sides accessible)

PJP prequalified joints include:

TC-P1: 45° single-bevel T-joint with PJP; effective throat = depth of groove less 1/8 inch [3 mm] for groove angles under 60°
BC-P3: single-V butt with specified root face; effective throat per geometry

Any deviation from the listed geometry — a 35° bevel when Clause 5 specifies 45° minimum, a root face outside tolerance, a backing configuration not shown — takes the joint out of prequalified status and requires PQR support. See Prequalified WPS under AWS D1.1 and Joint design and prequalified geometries.

PQR requirements when prequalified route is unavailable

When the joint geometry doesn't match Clause 5, or when the project specification requires a procedure-qualified (non-prequalified) WPS, a PQR is needed.

For CJP groove weld PQR:

Full-thickness groove weld test plates
Tensile tests: two reduced-section tensile specimens per AWS D1.1:2025 requirements
Transverse bend tests: face and root bends for plate ≤1-1/2 inch; side bends for plate >1-1/2 inch
Macro examination of each weld pass to verify complete fusion
The PQR test result qualifies a range of plate thickness per Table 6.6 limits

For PJP groove weld PQR:

Test plate with the required groove geometry and effective throat
Macro examination to verify effective throat achieved
Tensile testing may be required if the design applies tension across the joint

A CJP PQR generally covers PJP joints in the same base metal group, process, and thickness range — you do not need a separate PQR for PJP if you have a valid CJP PQR. The converse is not necessarily true: a PQR qualifying only PJP does not automatically extend to CJP.

See PQR tensile and bend test requirements for the full testing matrix.

NDE requirements: where the real difference shows

CJP joints carry volumetric NDE requirements in AWS D1.1:2025 for statically loaded tension applications and all dynamically loaded structures:

UT per the applicable clauses for plate thickness ≥5/16 inch [8 mm]
RT as an alternative to UT for plates up to 1-1/2 inch
MT or PT for surface inspection at CWI's discretion or per the contract NDE plan

Demand-critical CJP welds in AISC 341 seismic applications additionally require:

Prequalified or procedure-qualified WPS with CVN-tested PQR (if the project triggers CVN)
UT per AWS D1.1 and AISC 341 Appendix X acceptance criteria
Inspector hold points at fit-up, root pass, backgouge (if applicable), and final

PJP joints are typically exempt from volumetric NDE in AWS D1.1:2025. The inspector verifies:

Required effective throat via visual inspection of groove geometry at fit-up
Final visual weld profile and surface quality
MT or PT if specified by contract or if surface cracking is suspected

The logic: PJP joints are not designed for full tensile capacity. An internal inclusion in a PJP fillet doesn't automatically constitute a structural deficiency — the design already accounts for reduced effective throat. CJP, by contrast, is designed for full tension path integrity; any internal flaw is a concern.

WPS fields that must distinguish CJP from PJP

A WPS covering groove welds should explicitly state whether it applies to CJP, PJP, or both. The critical fields:

Groove type and geometry: WPS should specify the prequalified Clause 5 designation or describe the tested groove geometry (included angle, root opening, root face, backing type).

Effective throat: For PJP, document the minimum effective throat the WPS is qualified to achieve. For CJP, effective throat equals full plate thickness — state that explicitly.

Backing requirement: CJP open-root butt joints require back-gouging to sound metal and back-welding unless welding from both sides is approved. Solid steel backing allows single-sided CJP. PJP typically uses no backing bar; the root stop is the design throat.

NDE: The WPS or companion NDE plan should identify the NDE requirements for each joint type. If the WPS is applied to CJP joints in a tension load path, the NDE plan must include UT or RT.

A WPS that says only "groove weld" without specifying CJP or PJP is a common deficiency. See Common WPS deficiencies in third-party audits.

Field hold points for the inspector

Before welding (CJP):

Verify weld symbol specifies CJP — look for the "CJP" note or the closed-root symbol
Check fit-up geometry against the Clause 5 detail or PQR test plate sketch
Confirm WPS revision is current and covers the joint geometry, position, and base metal
Verify preheat

During welding (CJP):

Root pass: visually inspect for complete fusion before filling if access allows
Backgouge: inspect depth and profile before back-welding (hold point for CJP butt joints)
Track interpass temperature if CVN is required

Before welding (PJP):

Verify effective throat achievable from the fit-up geometry
Confirm WPS applies to PJP and covers the required throat

After welding:

CJP: UT or RT per NDE plan, visual, MT if required
PJP: visual, verify profile depth if measurable, MT per contract

For generating a GMAW procedure that covers CJP groove welds on A572 Grade 50, see the GMAW WPS generator. For the broader WPS writing process, see How to write an AWS D1.1 WPS.

FAQ

Frequently asked.

Does a PQR for a CJP groove weld also qualify PJP?: Generally yes — a PQR that qualifies complete joint penetration covers the more demanding condition, so partial joint penetration in the same base metal group and thickness range is typically supported. The reverse is not necessarily true: a PJP PQR does not automatically cover CJP joints.
What is the effective throat for a PJP groove weld?: Effective throat is the minimum distance from the joint root to the weld face, minus any reinforcement. For a PJP, effective throat is determined by the groove geometry and the depth of fusion achieved — and must equal or exceed the design-required throat. AWS D1.1:2025 Clause 5 lists effective throat for each prequalified PJP joint type.
Do PJP groove welds require UT or RT?: Not routinely. AWS D1.1:2025 requires volumetric NDE (UT or RT) for CJP groove welds in statically loaded tension and for all CJP groove welds in dynamically loaded structures. PJP groove welds are typically exempt from volumetric NDE unless the engineer or contract specifies otherwise.
Can I use a prequalified WPS for a CJP joint without a PQR?: Yes, if the joint matches an AWS D1.1:2025 Clause 5 prequalified CJP detail exactly — groove angle, root opening, root face, backing configuration, and base metal all within the prequalified limits. Any deviation from the Clause 5 geometry requires a qualified WPS backed by a PQR.