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What 外観検査 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 溶接サイズ versus drawing dimensions, profile conformance, and overall surface condition. The 検査員 per Clause 8.1.5 is responsible for ascertaining that all 製作 and erection by 溶接 is performed in conformance with the 要求事項 of the 契約図書 — which includes verifying WPS 適合, 予熱 application, and joint preparation in addition to the completed weld.

Clause 8.5.3 addresses visual aids: "Visual inspection for 割れ in welds and 母材 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 すみ肉溶接 gauges to 確認 leg サイズ and throat, アンダカット gauges to measure 不連続 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 仕様書.

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 読み込み済み and cyclically loaded connections. All eight items must be satisfied for the weld to be accepted.

(1) Cracks — Zero Tolerance

Any 溶接割れ 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 最小 size below which a crack is permitted.

(2) Fusion

No 融合不良 at the weld surface is permitted. The 溶接金属 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 開先溶接 reinforcement. 過大余盛 (a high, peaked weld crown) and 過大へこみ (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 温度. 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 水素割れ 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 限界値 vary by loading type and base metal 板厚. 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 気孔 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 溶接の種類 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 — 開先角度, ルート間隙, ルート面, 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 パス間温度 to confirm it stays within WPS limits, verifies pass sequence where the WPS prescribes one, and checks that craters are filled before the 溶接士 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 放射線透過試験 (RT) "when such inspection is required by the contract documents." Clause 8.19.1 and Clause 8.14 similarly provide for 超音波探傷試験 (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 チェックリスト, see the preheat calculator. For CWI certification context, see the certified welding inspector reference.

Beyond surface acceptance, the inspector also confirms that the weld was made within the 重要変数 ranges established in the PQR documentation. For welds on high-carbon or high-焼入性 steels that require post-weld 熱処理 for stress relief, visual inspection occurs both before and after the heat treatment cycle.

"All welds shall be visually inspected and shall be acceptable if the criteria of Table 8.1 are satisfied. Visual inspection of welds in all steels may begin immediately after the completed welds have cooled to ambient temperature."

— D1.1:2025 Clause 8.9, Visual Inspection