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Welding InspectionDefects/Repairs
Course Reference WIS 5Copyright © 2003 TWI Ltd M.S.Rogers
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WeldWeld DefectsDefects
Defects which may be detected by is!al i"spectio" ca"
be gro!ped !"der fie headi"gs
# Crac$s
# %olid i"cl!sio"s
# %!rface a"d profiles
# &isalig"me"t 'set(!p
irreg!larities)
# *as pores a"d
porosity
# Lac$ of f!sio"
# &echa"ical damage
# +are"t material damage
# &iscella"eo!s
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Crac$sCrac$s
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Crac$sCrac$s
Crac$s that may occ!r i" welded materials are ca!sed
ge"erally by by ma"y factors a"d may be classified byshape a"d positio", crac$s are classed as pla"ar-
Classified by Shape
#
Lo"git!di"al
# Tra"serse
#
.ra"ched
#
Chero"
Classified by Position
#
1# Ce"treli"e
#
Crater
#
!sio" o"e
# +are"t metal
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+rocess+rocess Crac$sCrac$s
ƒ ydroge" i"d!ced cold crac$i"g'ICC)
ƒ %olidificatio" crac$i"g 'ot Teari"g)
ƒ Lamellar teari"g
ƒ Re heat crac$i"g
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Crac$sCrac$s
Lo"git!di"al pare"t metal crac$ Tra"serse weld metal crac$
Lo"git!di"al weld metal crac$ Lamellar teari"g
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Transverse crack Longitudinal crackCopyright © 2003 TWI Ltd M.S.Rogers
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I"cl!sio"sI"cl!sio"s
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*as*as CaitiesCaities
Gas pore
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*as*as CaitiesCaities
PorosityPorosity
RooRoott pipingpiping
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Cluster porosity Herring bone porosityCopyright © 2003 TWI Ltd M.S.Rogers
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%olid%olid I"cl!sio"sI"cl!sio"s
Slag inclusions are defined as a non-metallic inclusion
caused by some welding process ƒ %lag origi"ates from weldi"g
fl!4
ƒ &* a"d TI* weldi"g
process prod!ce silica%lag i"cl!sio"s Lac$ of sidewall
f!sio" withassociated slag
i"cl!sio"s
ƒ %lag is ca!sed byi"ade5!ate clea"i"g
ƒ 6ther i"cl!sio"s i"cl!det!"gste" a"d copper
i"cl!sio"s from the TI* a"d+arallel slag li"es Lac$ of i"ter!"
f!sio" 7 slag
Copyright © 2003 TWI Ltd
&* weldi"g processM.S.Rogers
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Interpass slag inclusionsCopyright © 2003 TWI Ltd
Elongated slag linesM.S.Rogers
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Lac$Lac$ of of !sio"!sio"
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%!rface%!rface a"da"d profileprofile DefectsDefects
I"complete filled grooe
7 Lac$ of sidewall f!sio"
1
ƒ
+oor welder s$ill
ƒ I"correct electrode
ma"ip!latio"
ƒ
rc blow
ƒ I"correct weldi"g
c!rre"t/oltage
2
8- Lac$ of sidewall f!sio"
2- Lac$ of i"ter(r!" f!sio"
ƒ I"correct trael speed
ƒ I"correct i"ter(r!" clea"i"g
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6erlap6erlap
An imperfection at the toe or root of a weld caused by
metal flowing on to the surface of the parent metal
without fusing to it
ƒ Co"tami"atio"
ƒ %low trael speed
ƒ I"correct weldi"g tech"i5!e
ƒ C!rre"t too low
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6erlap6erlap
ToeToe OverlapOverlap
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RootRoot DefectsDefects
ƒ
Low mps/olts
I"complete root f!sio"
I"complete root pe"etratio"
ƒ Large Root face
ƒ
%mall Root *ap
ƒ ast Trael %peed
ƒ I"correct 9lectrode "gle
ƒ Co"tami"atio"
ƒ rc blow
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RootRoot DefectsDefects
Lack of root fusionLack of root Penetration
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Lack of root penetration Lack of root fusionCopyright © 2003 TWI Ltd M.S.Rogers
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%!rface%!rface a"da"d +rofile+rofile
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+rofile+rofile DefectsDefects
I"complete filled grooe +oor cap profile
Poor cap profiles and excessive
cap reinforcemens ma! lead o
sress concenraion poins ahe weld oes and will also
conri"ue o overall poor oe
"lend 94cessie cap height
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Excess cap reinforceentCopyright © 2003 TWI Ltd Incoplete filled grooveM.S.Rogers
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+rofile+rofile DefectsDefects
Poor stop!starts
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&iscella"eo!s&iscella"eo!s DefectsDefects
• 94cessie c!rre"t• Damp electrodes
• Co"tami"atio"
• I"correct wire feed speed
whe" weldi"g with the &*
"patter
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&iscella"eo!s&iscella"eo!s DefectsDefects
ƒ ccide"tal stri$i"g of the arc
o"to the pare"t material
ƒ a!lty electrode holder
ƒ +oor cable i"s!latio"
#rc strike
ƒ +oor ret!r" lead clampi"g
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:"derc!t:"derc!t
An irregular groove at the toe of a weld run in the
parent metal • 94cessie amps/olts
• 94cessie trael speed
• I"correct electrode a"gle
• 94cessie weai"g• I"correct weldi"g tech"i5!e
• 9lectrode too large
M.S.Rogers
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CapCap :"derc!t:"derc!t
&eas!red&eas!red i"i" bothboth Le"gthLe"gth ;; DepthDepth
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Root undercutCopyright © 2003 TWI Ltd Cap undercut M.S.Rogers
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%hri"$age%hri"$age *rooe*rooe
M.S.RogersCopyright © 2003 TWI Ltd
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Y A shallow groove caused by contraction in the weld metal along each side of the penetration bead
ƒ I"s!fficie"t weld metal
deposited i" the root pass
%hri"$age grooe
ƒ Too fast a cooli"g rate d!ri"g
the applicatio" of the root
bead pass
ƒ
+oor weldi"g tech"i5!e
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Co"caeCo"cae RootRoot
M.S.RogersCopyright © 2003 TWI Ltd
T E
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Y A shallow groove, which may occur in the root of a butt weld
ƒ Root faces too large
ƒ Root gap too large
Co"cae root
ƒ 94cessie bac$ p!rge press!re
d!ri"g TI* weldi"g
ƒ 94cessie root bead gri"di"g
before the applicatio" of theseco"d pass
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%!c$l "ac#l
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94cessie94cessie RootRoot +e"etratio"+e"etratio"
T E C
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YRoot penetration bead in excess in accordance with therelevant specification being used
ƒ Root faces too small
ƒ Root gap too large
94cessie root pe"etratio"
ƒ 94cessie amps/olts
ƒ
%low trael speed
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.!r".!r" Thro!ghThro!gh
A localized collapse of the weld pool due to excessive
penetration resulting in a hole in the root run
ƒ igh mps/olts
ƒ
%mall Root face
ƒ Large Root *ap
.!r" thro!gh ƒ %low Trael %peed
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Root Defects
$urn
T%roug%
Copyright © 2003 TWI Ltd $urn t%roug% M.S.Rogers
R tR t C $i /6 idi dC $i /6 idi d R tR t
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RootRoot Co$i"g/64idiedCo$i"g/64idied RootRoot
ƒ Loss or i"s!fficie"t bac$
p!rgi"g gas
ƒ &ost commo"ly occ!rs
whe" weldi"g stai"lesssteels
ƒ +!rgi"g gases i"cl!de
argo", heli!m a"doccasio"ally "itroge"
Copyright © 2003 TWI Ltd M.S.Rogers
C tC t +i
+i
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Crater Crater +ipe+ipe
Crater pipe is a shrinkage defect and not a gas defect, it
has the appearance of a gas pore in the weld crater
ƒ Too fast a cooli"g rate
Crater crack&"tar crack'
ƒ Deo4idiatio" reactio"sa"d
li5!id to solid ol!me
cha"ge
ƒ Co"tami"atio"
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Copyright © 2003 TWI Ltd M.S.Rogers
C tC t +i
+i
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Crater Crater +ipe+ipe
WeldWeld crater crater
Crater Crater pipepipe
Copyright © 2003 TWI Ltd M.S.Rogers
C tC t +i /C $
+i /C $
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Crater Crater +ipe/Crac$s+ipe/Crac$s
Crater Crater CracksCracks
Crater Crater pipepipe
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&echa"ical&echa"ical DamageDamage
Copyright © 2003 TWI Ltd M.S.Rogers
& h i l&echa"ical DDamage
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&echa"ical&echa"ical DamageDamage
&echa"ical damage ca" be defi"ed as a"y s!rface material
damage ca!se d!ri"g the ma"!fact!ri"g process-This ca" i"cl!ded damage ca!sed by<
ƒ *ri"di"g
ƒ
ammeri"g
ƒ Chiselli"g
ƒ Chippi"g
ƒ
.rea$i"g off welded attachme"ts 'tor" s!rfaces)
ƒ :si"g "eedle g!"s to compress weld cappi"g r!"s
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%e%ett(!p(!p Irreg!laritiesIrreg!larities
Copyright © 2003 TWI Ltd M.S.Rogers
%%ett I l iti
!pIrreg!larities
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%e%ett(!pIrreg!larities(!pIrreg!larities
$inear misali%nmen is measured
from he lowes plae o he
hi%hes poin of he cap
+late/pipe Li"ear &isalig"me"t
'i(Lo)
&n%ular misali%nmen is
measured in de%reeso
"g!lar &isalig"me"t
Copyright © 2003 TWI Ltd M.S.Rogers
Li"earLi"ear &isalig"me"t
&isalig"me"t
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Li"ear Li"ear &isalig"me"t&isalig"me"t
ighest poi"t
of the capmm
Lowest plate
Copyright © 2003 TWI Ltd M.S.Rogers
+ t+ t & t i l& t i l D f tD f t
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+are"t+are"t &aterial&aterial DefectsDefects
weldi"g i"spector sho!ld also i"spect the pare"t
material for a"y isible defects
&echa"ical damage Lap
Lami"atio"
%egregatio" li"e
Copyright © 2003 TWI Ltd
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