ACCEPTANCE CRITERIA OF WELD DEFECTS AS PER DIFFERENT CODE ( ASTM B 31.1 / AWS D1.1)

ACCEPTANCE CRITERIA OF WELD DEFECTS AS PER DIFFERENT CODES:

ASTM B 31.1 BOILER PIPING CODE

VISUAL EXAMINATION – Acceptance criteria

Cracks on external surface

Undercuts on external surface > 1 mm deep

Weld reinforcement more than specified

Lack of fusion on surface

Incomplete penetration in root if accessible

ASTM B 31.1 BOILER PIPING CODE

MAGNETIC PARTICLE EXAMINATION –

Relevant indication is one from unacceptable

mechanical discontinuities. Size of indication is the

criteria and not the size of defect.

Acceptance criteria

Cracks or linear indication ( L > 3 W)

Rounded indications dimension > 4.8 mm

Four or more rounded indications in a line

separated by 1.6 mm edge to edge

Ten or more rounded indications in any 6 sq. in.

surface with major dimension < 6 in

ASTM B 31.1 and ASME VIII

RADIOGRAPHIC EXAMINATION –

Acceptance criteria

Cracks or incomplete fusion

Elongated indications

6.4 mm for thickness up to 19 mm

1/3 t for thickness from 19 - 56 mm

19 mm for thickness more than 56 mm

Group of aligned indications with aggregate

length more than t in a length of 12 t

Rounded indications as per chart

ASME VIII BOILER & PR VESSEL CODE

ROUNDED INDICATIONS –

A sequence of 4 or more rounded indications are

aligned when they touch a line parallel to length of

line drawn through center of outer indications

thickness

Relevant indication

1/8 “ t / 10

1/8 to 1/4”. 1/64”

1/4 to 2” 1/32”

> 2” 1/16”

ASME B 31.3 PROCESS PIPING CODE -

NON DESTRUCTIVE EXAMINATION REQUIRED

• Visual examination of randomly selected

materials

• Visual examination of 5% min of fabrication

• 100% visual examination of longitudinal welds

• Random visual examination during erection of

piping for defects which require repair

• Minimum 5% of circumferential butt welds shall

be examined by random RT. For cyclic loaded pipe,

100% RT needed

• When circ. joint intersects with long. joint at

least 38 mm of each intersecting weld shall be

Acceptance Criteria as per ASME B 31.3

Normal fluid service

(a) Crack, Lack of fusion (VT &RT) No evident imperfection

(b) Incomplete penetration (VT & RT) in Long grooves no

evident imperfection. In girth welds and branch conn., depth

permitted is 1 mm and 0.2 t. Cumulative <38 mm in any

150 mm weld length

(c) Internal porosity (RT) in girth, long, branch con., as per

ASME VIII

(d) Slag / W inclusion (RT) in girth, long and branch welds -

individual length < 2t, individual width < 3 mm & 0.5 t,

cumulative length <4t in any 150 mm weld length

(e) Undercut(VT) in girth, fillet and branch welds - depth < 1

mm & 0.25 t. For long welds no evident undercut

Acceptance Criteria as per ASME B 31.3

Normal fluid service

(f) Surface porosity (VT) No evident imperfection

(g) Concave root surface in butt welds (VT & RT) - Total

joint thickness incl weld reinf > t

(h) Reinforcement or internal protrusion (VT)

t Max height

<=6 1.5

6 to 13 3

13 to 25 4

>25 5

Acceptance Criteria as per ASME B 31.3

Severe cyclic condition

(a) Crack (VT,RT,MT,PT), Lack of fusion (VT,RT) - No evident

imperfection

(b) Incomplete penetration (VT & RT) in girth, long and

branch welds no evident imperfection.

(c) Internal porosity (RT) in girth, long, branch con., as per

ASME VIII

(d) Slag / W inclusion (RT) in girth, long and branch welds -

individual length < t/3, individual width < 2.5 mm & t/3,

cumulative length < t in any 12 t weld length

Acceptance Criteria as per ASME B 31.3

Category D fluid service

(a) Crack (VT) - No evident imperfection

(b) Lack of fusion (VT) in long & branch weld - No evident

imperfection. In girth weld, depth < 0.2 t cumulative length

< 38 mm in any 150 mm length

(c) Incomplete penetration (VT ) in girth weld same as lack

of fusion. In long weld no evident imperfection. In branch

welds depth < 1 mm & 0.2 t. Cumulative length < 38 mm in

any 150 mm length

(d) Undercut (VT) in girth weld < 1.5 mm & < t/4. In long

weld no evident imperfection. In fillet and branch weld < 1

mm & t/4

(e) Surface porosity (VT) no evident imperfection

Acceptance Criteria as per ASME B 31.3

Category D fluid service

(f) Concave root surface in butt welds (VT) - Total joint

thickness incl weld reinf > t

(g) Reinforcement or internal protrusion (VT)

t Max height

<=6 3.0

6 to 13 6

13 to 25 8

>25 10

AWS D 1.1 STRUCTURAL WELDING CODE

Static load, Cyclic load & Tubular connections

(a) Crack

Weld shall have no crack

(b) Weld / Base Thorough fusion shall exist bet’ WM/BM

metal fusion and adjacent layers of WM

(c ) Crater

Crater to be filled to full cross section

except for stitch welds outside eff. Len.

(d) Weld profile In conformance with sketch

(e) Inspection VT to start after weld cools to room temp

(f) UnderrunUnderrun in fillet weld nominal size 1.6

mm provided it is < 10% length. In Web to

flange welds,

AWS D 1.1 STRUCTURAL WELDING CODE

(g) Undercut In static loading, 1 mm permitted for t<25

and 1.6 mm in t>25mm. For t<25 mm, Max

1.6 mm

permitted for accumulated l of 50

mm in 305 mm.

In cyclic loads and tubular connections,

undercut

< 0.25 mm deep when weld is

transverse to tensile

stress. For other cases,

1 mm is permitted

(h) Porosity In complete joint penetration butt joints

transverse to tensile stress, no visible piping

porosity

permitted in static, cyclic & tubular

connection

AWS D 1.1 STRUCTURAL WELDING CODE

Porosity In static loading, for other grooves and

fillets

sum of porosity with dia > 1mm,

should be < 10 mm in

any linear inch of

weld and < 19 mm in any 305 mm

weld

For cyclic loading and tubular connection,

the

frequency of piping porosity in other

cases should be <

one in 100 mm weld

length and max dia < 2 mm.

In cyclic loading and tubular connections,

for

fillet welds connecting stiffeners to web,

the sum of dia

of piping porosity<10 mm in

any linear inch of weld

and shall be < 19

mm in any 305 mm weld

AWS D 1.1 STRUCTURAL WELDING CODE

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RADIOGRAPHY FOR STATICALLY LOADED STRUCTURE

Elongated indication and spacing as per chart

Rounded indications > E/3 not to exceed 6 mm (except

for t>2” it is 10 mm) and gap should be > 3 L

Isolated discontinuities like clusters with sum of

dimensions not to exceed chart and gap < 3 L

Sum of individual discontinuities each having max

dimension < 2 mm, shall not exceed 2 E /3 (10 mm max) in

any linear inch of weld.

In line discontinuities with sum of greatest dimension <

E in any 6E length of weld