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What Visual Inspection Covers Under D1.1

Clause 8.9 establishes the requirement in direct terms: "All welds shall be visually inspected and shall be acceptable if the criteria of Table 8.1…are satisfied." There is no sampling provision. Every production weld on the project must pass the Table 8.1 acceptance criteria before it can be accepted.

The scope of visual inspection under D1.1 covers weld size versus drawing dimensions, profile conformance, and overall surface condition. The inspector per Clause 8.1.5 is responsible for ascertaining that all fabrication and erection by welding is performed in conformance with the requirements of the contract documents — which includes verifying WPS compliance, preheat application, and joint preparation in addition to the completed weld.

Clause 8.5.3 addresses visual aids: "Visual inspection for cracks in welds and base metal and other discontinuities should be aided by a strong light, magnifiers, or such other devices as may be found helpful." The word "should" indicates a recommendation, not a requirement, and D1.1 does not specify a numerical lighting value. The choice of tools is left to the inspector's judgment.

In practice, inspectors use fillet weld gauges to verify leg size and throat, undercut gauges to measure discontinuity depth, and tape measures to verify weld length and joint preparation dimensions. A strong flashlight and hand magnifier address Clause 8.5.3 in the field without any special equipment specification.

Table 8.1 — The Eight Acceptance Criteria

Table 8.1 defines acceptance criteria for visually inspected welds under D1.1:2025. The criteria differ for statically loaded and cyclically loaded connections. All eight items must be satisfied for the weld to be accepted.

(1) Cracks — Zero Tolerance

Any crack is unacceptable, regardless of size or location. This zero-tolerance criterion applies to both statically and cyclically loaded connections without exception. A cracked weld is rejected and must be removed and rewelded — there is no minimum size below which a crack is permitted.

(2) Fusion

No incomplete fusion at the weld surface is permitted. The weld metal must fuse completely to the base metal and to adjacent weld passes at the weld surface. Visible lack of fusion at the weld face or toe is rejectable.

(3) Crater

All craters shall be filled before the arc is moved away from the weld. An unfilled crater left at the end of a weld run is rejectable. This applies to every pass, not only the final pass — interpass craters must also be filled before proceeding.

(4) Weld Profiles

Weld profiles must conform to Clause 7.23, which governs convexity, concavity, and reinforcement. Clause 7.23.1 addresses fillet weld profiles and Clause 7.23.3 addresses groove weld reinforcement. Excessive convexity (a high, peaked weld crown) and excessive concavity (an underweight, hollow weld face) are both rejectable conditions under Clause 7.23.

(5) Time of Inspection

For most steels, visual inspection may begin immediately after completed welds have cooled to ambient temperature. For ASTM A514, A517, and A709 Grade HPS 100W steels, acceptance shall be based on visual inspection performed not less than 48 hours after completion of the weld. This hold period allows delayed hydrogen cracking to manifest before the inspection record is finalized. If a weld on these steels is inspected early, the record is not valid and inspection must be repeated after the full 48-hour hold.

(6) Undersized Fillet Welds

Undersized fillet welds are permitted to a limited extent. The underrun shall not exceed 10% of the weld length. This means a 10-inch fillet weld may be undersized for no more than 1 inch of its total length. The undersized portion must also not be located at the weld's ends, where stress concentrations are highest. Undersized fillet welds beyond the 10% limit are rejectable and must be corrected by additional welding.

(7) Undercut

Undercut depth limits vary by loading type and base metal thickness. For statically loaded connections: undercut shall not exceed 1/32 in for base metal less than 1 in thick, and shall not exceed 1/16 in for base metal 1 in thick or greater. For cyclically loaded connections: primary tension members are limited to 0.01 in; all other cyclic members are limited to 1/32 in. For a complete breakdown of undercut limits and measurement procedure, see the weld undercut acceptance criteria reference.

(8) Piping Porosity

For CJP groove welds transverse to computed tensile stress, zero visible piping porosity is permitted under statically loaded conditions. For fillet welds and other groove welds under static loading, the sum of visible piping porosity 1/32 in or greater in diameter shall not exceed 3/8 in per linear inch of weld. Cyclically loaded connections carry tighter limits. For the full breakdown of porosity acceptance criteria by weld type and loading condition, see the weld porosity acceptance criteria reference.

The Inspection Sequence

Visual inspection under D1.1 is not a single end-of-job check. Effective VT occurs in three phases: before welding begins, during welding, and after the weld is complete.

Before welding: The inspector verifies joint preparation against the WPS — groove angle, root opening, root face, cleanliness, and fitup. Preheat must meet the minimum temperatures established by Table 5.11 (Clause 5.7) and confirmed per Clause 7.6 before the first arc is struck. The WPS itself must be reviewed to confirm it covers the material, thickness, position, and process being used.

During welding: The inspector observes interpass temperature to confirm it stays within WPS limits, verifies pass sequence where the WPS prescribes one, and checks that craters are filled before the welder breaks arc. Interpass cleaning must be adequate before the next pass is deposited.

After welding: Completed welds are allowed to cool to ambient temperature (or held 48 hours for A514/A517/A709 HPS 100W). The inspector then checks all eight Table 8.1 criteria: cracks, fusion, craters, profile, size, undercut, and piping porosity. Dimensional verification confirms weld size and length match the drawing requirements.

When VT Is Not Sufficient

Visual inspection is capable of detecting surface-breaking and near-surface discontinuities — cracks that break the surface, incomplete fusion at the weld face, undercut, visible porosity, and profile defects. It cannot detect defects buried within the weld cross-section.

Subsurface defects — buried porosity, slag inclusions, lack of fusion below the weld surface, and incomplete penetration in groove welds — require volumetric examination. Clause 8.16.1 provides for radiographic testing (RT) "when such inspection is required by the contract documents." Clause 8.19.1 and Clause 8.14 similarly provide for ultrasonic testing (UT) when the contract documents require it. Neither RT nor UT is mandatory under D1.1 itself — the contract documents must specify them.

A weld that passes VT may still contain internal defects that would fail RT or UT. Passing visual inspection means the weld surface meets Table 8.1 — it is not a statement about internal soundness. For the complete taxonomy of weld discontinuities detectable by VT, RT, and UT, see the weld defects reference.

For questions about preheat requirements that feed into the pre-weld inspection checklist, see the preheat calculator. For CWI certification context, see the certified welding inspector reference.