Does AWS D1.1 require visual inspection before NDE on completed welds?

Yes. Visual examination of completed welds must occur before any volumetric or surface NDE method is applied. A weld that fails visual acceptance criteria under AWS D1.1 Table 9.1 does not need to proceed to UT, RT, MT, or PT—the visual failure drives the disposition decision first.

How long must a CWI wait after welding to perform NDE on high-strength steel?

AWS D1.1 requires a minimum delay after welding before NDE on steels with a specified minimum yield strength of 50 ksi or greater, or when the deposited weld metal has minimum tensile strength exceeding 70 ksi. The minimum delay is 24 hours for most cases, but the CWI and QC plan should verify whether the specific material or application requires a longer hold period.

What is the CWI required to inspect before welding begins under AWS D1.1?

Pre-weld inspection under AWS D1.1 Clause 8 covers joint preparation and fit-up dimensions, base metal identification, WPS review (confirmed applicable procedure, correct revision), preheat measurement, welder and welding operator identification confirmed against valid WPQ, and welding equipment calibration status. Skipping any of these at the pre-weld stage creates a nonconformance that cannot be resolved retroactively.

Can root pass inspection be waived if the joint has steel backing?

AWS D1.1 requires root pass inspection for open-root CJP groove welds before subsequent passes are applied. When a weld uses permanent steel backing that eliminates the open root, the physical access constraint changes, but the in-process inspection requirements for progressive passes remain. Never waive root pass inspection without explicit code authority or approved procedure.

CWI Weld Examination Sequence Under AWS D1.1

AWS D1.1 requires inspection at three phases—pre-weld, in-process, and post-weld—and each phase has a defined sequence. Getting the order wrong causes nonconformances that are expensive to resolve.

Inspection under AWS D1.1 is not a single event at the end of a welded joint's production. It is a sequence—pre-weld, in-process, post-weld—and within the post-weld phase there is a required order among the different examination methods. Executing inspections out of sequence or omitting a phase is not just a documentation problem; it creates nonconformances that may require destructive investigation to resolve.

This guide covers the full AWS D1.1 inspection sequence as it applies to structural groove and fillet welds, with emphasis on where CWIs and QC managers most commonly lose the thread.

Phase 1: Pre-Weld Inspection

Pre-weld inspection establishes that every condition required for a conforming weld is in place before the arc strikes. AWS D1.1 Clause 8 defines the CWI's inspection authority and scope. The pre-weld checklist covers:

Joint preparation and fit-up. Root opening, groove angle, root face dimension, and joint cleanliness must conform to the WPS and the applicable joint geometry—prequalified per Clause 5 or tested per Clause 6. For groove welds, the fit-up tolerance determines whether the joint can be welded as prepared or requires correction. Fit-up deficiencies beyond permissible tolerances must be resolved before welding.

Base metal identification. The material at the joint must be traceable to a mill test report (MTR) and confirmed as the base metal specified by the WPS. Identification marks, heat numbers, and CMTR documentation are confirmed at this stage, not during post-weld review. See CWI Pre-Weld Inspection: Before the Arc Strikes for the full pre-weld checklist.

WPS verification. The applicable WPS must be at the workstation, at the correct revision, and confirmed as valid for the joint type, base metal, process, position, and thickness range. The CWI verifies that the welder has reviewed the WPS and is operating within its parameters—not just that the document is present.

Preheat measurement. If the WPS specifies preheat, the CWI measures and documents the temperature at the required distance from the joint before welding begins. Preheat compliance at this stage is a mandatory hold point for many project quality plans; production welding that begins before preheat is confirmed creates a nonconformance that cannot be retroactively cured.

Welder identification and WPQ verification. The welder or welding operator assigned to the joint must hold a current, valid WPQ that covers the process, position, base metal group, and joint type. Continuity under AWS D1.1 Clause 6.4.1 must be current. CWI stamp or notation records which qualified welder performed each specific weld.

Phase 2: In-Process Inspection

In-process inspection occurs during welding. It addresses conditions that are only visible or measurable while the joint is open or between passes, and cannot be assessed after the weld is complete.

Root pass inspection. For CJP groove welds with an open root, the root pass must be inspected for fusion, undercut, cracks, and profile before the next pass covers it. This is the most time-critical hold point in structural groove weld inspection: the CWI must be present and must approve the root pass before subsequent passes proceed. On projects with a project quality plan (PQP), root pass inspection is typically listed as a mandatory hold point that stops production until the CWI signs off.

For joints welded with permanent steel backing, the root pass geometry differs, but in-process attention to root zone fusion remains important.

Interpass condition. Between passes, the CWI checks interpass temperature compliance (upper limit per WPS), slag removal (complete before next pass on SMAW and FCAW-G), pass sequence per the WPS, and weld bead profile for buildup defects. A pass that shows transverse cracking or piping porosity requires investigation and disposition before it is buried by subsequent passes.

Interpass visual of bead geometry. Wide, convex, or undercut beads that would violate weld profile limits if left in the final pass are correctable at the interpass stage but often require grinding or additional passes to address. Identifying them early reduces the repair cost.

For documentation of in-process observations, see Production Welding Parameter Log: CWI Documentation.

Phase 3: Post-Weld Examination Sequence

Post-weld examination of a completed structural weld follows a defined sequence. The sequence is not merely convention—it reflects a logical hierarchy where each method depends on the previous one having passed.

Step 1: Cooling and Hydrogen Diffusion Delay

After welding is complete, the joint must cool before any NDE. For materials with a specified minimum yield strength at or above 50 ksi, or when deposited weld metal strength exceeds specified minimums, AWS D1.1 requires a minimum hold period before NDE to allow hydrogen diffusion from the weld zone. The minimum required delay is typically 24 hours, though the CWI should confirm the project specification and the code's applicable provisions for the specific material combination.

Performing UT or RT immediately after welding on a high-strength steel joint without the required delay is not just a missed hold point—it produces unreliable NDE results and a documentation deficiency. See Post-Weld NDE Delay: Hydrogen Diffusion Requirements Under AWS D1.1 for the full requirements.

Step 2: Visual Examination

Visual examination of the completed weld is the first post-weld examination method applied, always. AWS D1.1 defines visual acceptance criteria covering:

Weld size (fillet leg dimension and effective throat)
Weld profile (convexity, concavity, underfill)
Undercut (depth limits vary by static vs cyclically loaded)
Overlap
Surface porosity
Cracks, unfused craters, and other surface discontinuities

A weld that fails visual acceptance criteria does not proceed to volumetric or surface NDE. The visual failure drives the disposition first—repair, reject, or engineering acceptance per the applicable process. Only after visual acceptance is confirmed does the CWI authorize the next examination method.

For the complete visual acceptance standard, see Visual Acceptance Criteria Under AWS D1.1.

Step 3: Surface NDE (MT or PT)

When the project specification or design requires magnetic particle testing (MT) or liquid penetrant testing (PT) in addition to visual, surface NDE is performed after visual examination passes and the weld surface is clean. MT detects subsurface discontinuities near the surface in addition to surface-breaking ones; PT is limited to surface-breaking discontinuities only. For ferromagnetic structural steel, MT is generally preferred.

Surface NDE is performed before volumetric NDE. A surface-breaking crack found by MT that runs to significant depth may change the inspection approach for UT or indicate that UT alone would be insufficient.

Step 4: Volumetric NDE (UT or RT)

Ultrasonic testing (UT) or radiographic testing (RT) is the last examination method applied, after visual and surface NDE have passed. Performing RT or UT before visual examination can waste film and technician time on a joint with visible surface defects that will trigger repair regardless of internal condition.

The timing of volumetric NDE is also subject to the hydrogen diffusion delay described above. UT calibration and scanning must follow the approved NDE procedure, which references the applicable acceptance criteria—AWS D1.1 Table 9.25 for UT rejection level for statically loaded structures, or the alternate criteria for cyclically loaded structures.

For timing requirements see NDE Inspection Timing: Post-Weld Delay Under AWS D1.1.

Step 5: Dimensional Inspection

Dimensional inspection—verifying that the completed weld assembly meets the drawing's geometric tolerances—is performed after NDE acceptance. This step confirms overall member length, sweep, camber, angular distortion, and weld-to-weld dimension relationships. Distortion caused by welding is measured and compared to tolerances in AWS D1.1 and the project specification.

Performing dimensional inspection before NDE creates a logical problem: a weld that fails NDE after dimensional acceptance was already recorded may require repair welding that re-introduces distortion, invalidating the dimensional inspection. Sequence matters.

Hold Points vs Witness Points

AWS D1.1 inspection requirements establish what the CWI must inspect; the project quality plan (PQP) or inspection and test plan (ITP) establishes whether each inspection point is a hold point (production stops until CWI signs off) or a witness point (CWI is notified and may attend; production may proceed with documented notification if CWI does not respond within a defined window).

Root pass inspection for CJP groove welds is typically a hold point. Post-weld visual of fillet welds on standard connections may be a witness point on low-risk, high-volume production. The designation affects how production flow is managed and how inspection delays are handled contractually.

For hold point and witness point management, see Weld Inspection Hold Points: CWI and Contractor QC vs Verification Inspection Under AWS D1.1.

Documentation Through the Sequence

Each phase generates records that form the inspection closeout package. Pre-weld records include fit-up checks, preheat measurements, and WPS assignments. In-process records capture root pass acceptance, interpass temperature logs, and any nonconformance observations. Post-weld records include visual acceptance sign-off, NDE reports, and dimensional inspection data.

The closeout package must trace each weld from pre-weld through final acceptance, with each phase signed by the responsible CWI. Incomplete records—a post-weld NDE report with no corresponding pre-weld documentation—are a common finding in AISC certification audits and third-party verification inspections.

For audit-ready documentation practices, see CWI Inspection Report Documentation Under AWS D1.1 and the NDE Documentation Audit Packet.

For digital inspection tracking and WPS management tools that support the full inspection lifecycle, see our pricing.

Rule library based on AWS D1.1:2025; verify against your governing edition (the AHJ or contract may specify 2020 or earlier).