AWS D1.1 2015 edition – Tolerance of joint details – Visual inspection

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🔧 1. Joint Detail and Fit-Up Tolerances in WPS

🔹 Clause 5.21.4.1 – Fit-Up Tolerance Requirements

Fit-up tolerances for groove weld assemblies are critical and must be addressed in the WPS.

Refer to:

• Figure 5.3 a, b, c – Different fit-up types (with/without backing, with/without backgouging)

• Tolerance parameters include:

  • Root opening (often ±1.6 mm / ±1/16 in.)

  • Root face

  • Groove angle

  • Alignment/mismatch (hi-lo)

⚠️ Out-of-tolerance fit-up (e.g., root opening > 20 mm) is not allowed unless qualified by a PQR — especially for PJP groove welds, where excessive root gap is a nonessential variable turning essential.

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📐 2. Essential Variables in WPS (Clause 4 and Table 4.5)

✅ Table 4.5, Line 31 – Groove Type

Change in groove type (e.g., single-V → double-V) requires requalification, unless:

• It’s a CJP groove weld meeting Clause 3.12, 3.13 (prequalified) or Clause 9.10, 9.11 (tubular connections).

• Then, any groove detail conforming to those figures (e.g., Figure 3.2, 3.3) is acceptable.

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✅ Table 4.5, Line 33 – Fit-Up Tolerances

Changes exceeding tolerance in:

• Groove angle (decrease)

• Root opening (decrease)

• Root face (increase)

🛑 These are essential variables, requiring PQR requalification if exceeded.

🔍 Reference tolerance limits:

• Clause 3.12 / 3.13 – Prequalified CJP joint tolerances (Figure 3.2 and 3.3)

• Clause 5.21.4.1 / Figure 5.3 – Assembly tolerance for qualified WPS

• Clause 9.10 – 9.11.2, 9.24.2.1 – Tubular and special connections

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🧾 3. How to Set Up Weld Joint Details in pWPS

a) Select Appropriate Joint Type

• Use Figure 3.3 for CJP groove weld if prequalified.

• Clearly indicate:

  • Groove type (e.g., double-V)

  • Backing or backgouging

  • Weld size (PJP) or “CJP” note

  • Joint dimensions and tolerances

b) Include Fit-Up Tolerances

Refer to:

• Figure 5.3 – Tolerance for groove weld assemblies

• Figure 9.7 to 9.16 – For tubular joint fit-up tolerances

🛠️ Mark allowable:

• Root opening

• Groove angle

• Root face

• Mismatch

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📏 4. Weld Profile Requirements

Refer to:

• Figure 5.4 – Weld Profiles

  • Convexity limits

  • Undercut, overlap, reinforcement

  • Fillet weld leg size and throat

• Define in pWPS or attach diagram

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👁️ 5. Visual Inspection Acceptance Criteria

Refer to:

• Table 6.1 – Visual Inspection Criteria (CJP/PJP)

• Table 9.16 – Tubular Structures VT Criteria

Common inspection tolerances:

Inspection Item	Acceptance Criteria
Undercut (static)	≤ 1/32 in. (1 mm)
Weld reinforcement	≤ 1/8 in. (3 mm) for groove welds
Weld size (fillet)	No less than design; oversize usually not restricted
Overlap	Not permitted

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✅ Quick Reference Summary

Element	Clause / Figure	Description
Joint details	Clause 5.21.4.1	Fit-up tolerance for groove welds
Groove dimensions	Clause 5.21.4 / Figure 5.3	Root opening, face, angle
Fillet/PJP assembly	Clause 5.21.1 / 5.21.2	Pre-weld joint prep
CJP joint detail	Clause 3.12 / Figure 3.3	Prequalified groove detail
Essential variables	Table 4.5, Lines 31 & 33	Groove type & fit-up change
Weld profile	Figure 5.4	Inspection of weld surface profile
Visual inspection	Table 6.1, 9.16	VT acceptance for CJP/PJP welds

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