Acceptance Criteria for weld imperfection
ASME B31.3 Table 341.3.2
No.
Imperfection
1 Crack (VT,RT,MT,PT)
Lack of fusion
2 (VT,RT)
Normal & M fluid Service
Severe cyclic Condition
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Incomplete
Depth ≤ 1 mm (1⁄32 in.) and ≤ 0.2T w
Penetration
Total Length ≤ 38 mm (1.5 in.) in 150mm
(VT,RT)
weld length
3 Note:Tightly butted unfused root faces are unacceptable.
Thk.
<6mm
Not Acceptable
Depth ≤ 0.2T w Total
Length ≤ 38 mm (1.5 in.) in
150mm weld length
Depth ≤ 0.2T w Total
Length ≤ 38 mm (1.5 in.) in
150mm weld length
Not Acceptable
Nonrelevent(m
m)
Nonreleven
Random
Isolated t(mm)
Thk.
0.38mm
1/4 t
1/3 t
<6mm 1/4 t 1/3 t 0.38mm
8-17mm
8-17mm
1/4
t
x1.5
1/3
t
x1.5
0.79mmx1.5
1/4 t 1/3 t 0.79mm
Internal Porosity
19-50mm 4mmx1.5 6.3mmx1.5 0.79mmx1.5 19-50mm 4mm
6.3mm 0.79mm
(Ref: Sec VIII
4 Appendix 4) (RT) >50mm 4mmx1.5 9.5mmx1.5 1.6mmx1.5 >50mm 4mm 9.5mm 1.6mm
length ≤ 2T w Width ≤ 3 mm (1⁄8 in.) length ≤ T w /3 Width ≤ 2.5 mm
Internalslag,tungsten
and ≤ T w /2
(3⁄32 ") and ≤ T w /3 Total length
inclusion, elongated
Total length ≤ 4T w in 150 mm
≤ 12T w weld length
5 Indication (RT)
Random
Isolated
Undercutting
Depth ≤ 1 mm (1⁄32 in.) and ≤ T w /4
6 (VT,RT)
Surface porosity
Not Acceptable (VT)
7 Evaluated only for welds ≤ 5mm in nominal Thickness
Root Concavity
8 (VT,RT)
Depth=Total joint thickness, incl. weld
reinf., ≥ T w
Thk.
<¼"(6mm)
Reinforcement or ¼" - ½" (6mm-13)
internal protrusion ½" - 1"(13mm-25)
>1"(25mm)
9
(VT)
D fluid Service
Not Acceptable
Not Acceptable (VT)
Not Applicable
Not Applicable
Depth ≤ 1.5 mm (1⁄16 ")
and ≤ *T w/4 or 1 mm
(1⁄32 in.)]
Not Acceptable (VT)
Depth=Total joint
Depth=Total joint thickness, incl. thickness, incl. weld reinf.,
≥Tw
weld reinf., ≥ T w
Reinfo.
1/16" (1.5mm)
1/8"(3mm)
5/32" (4mm)
3/16"(5mm)
Same as "M" fluid Service
criteria
Notes:
1 The above Table is applicable only for Girth & Mitre groove joint.
2 "And" indicates lesser value & "Or" for larger value
3 T w is the nominal wall thickness of the thinner of two components.
Twice of the 'M' fluid
service value