weld defects - training 2

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  • 8/18/2019 Weld Defects - Training 2

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    CPC Expansion Project,

    Kazakhstan Section /Проект рас !ре"!# $%$,

    $а&а'ста"ск!( )*асток

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    +e - .e ects / 0е1ект с2ар"о3о 2а

    Weld defects are deflections outside of the acceptance limits, which decreasing thestability or the functionality of the welded structure. /Дефекта ! "#а$%&'& (#а) *#+* т"* &тк+&%е%!*, к&т&$-е $е#-(а т & 0"т! -е

    $е е+-, 0 е%1(а 2!е "та3!+1%&"т1 !+! ф0%к4!&%а+1%&"т1 "#а$%&5 к&%"т$0к4!!.

    Weld defects can occur in any position in the weld and may be 6isible on the radiographfor assessment. / 7$! $е е%!! &4е%к!, "#а$%-е ефект- &'0т #&8%!кат1 #+ 3& &+&9е%!! "#а$%&'& (#а, ! &'0т 3-т1 #! %- %а $а !&'$аф!:е"к&!8&3$а9е%!5.

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    45pe o -e ects occ6rre- -6rin7 8e -in7 o 9:; pipe ine< /$ате3ор!! =е1екто2 2о&"!ка>?!е 2 @роAессе с2арк! 9:

    =>(Bо2о3о тр) о@ро2о=а

    ; lag ?nclusion / @+ак&е #к+ :е%!е; ?ncomplete =enetration / Aе &+%-5 $а$; BacC of Dusion / Aе &"тат&:%&е " +а#+е%!е; Eoot Fonca6ity / G&'%0т&"т1 &3$ат%&5 "т&$&%- (#а; Hurn Ihrough / 7$&9&' J"к#&8%&е &т#е$"т!еK

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    Dn-erc6t /По=ре& Bета а 2а

    +hat is itF / Gто Hто такоеF; Ihis is an irregular groo6e at the toe of a run in the parent metal. /Lт& 0 е%1(е%!е т&+2!%- &"%%&'& ета++а # #! е ка%а#&к, 0 '$а%!4 "#а$%&'& (#а.+here can Ie o6n-F / J=е !' Bо "о "а(т!F; Mt surface of a completed Noint / Aа е$O%&"т! 8ак&%:е%%-O "#а$%-O (#.; Mt the toes of each pass of a multi)run weld / G %!9%е к&%4е ка9 &'&

    %&'& $&O& %&'& (#а.+hat -oes ca6se itF / Пр!*!"а =е1ектаF; Wide spreading arc Jhigh arc 6oltageK / @!$&к&е $а" $&"т$а%е%!е 0'! J#-"&к&е

    %а $*9е%!е # 0'еK.; ?nsufficient fill Jlow current or high tra6el speedK / Aе &"тат&:%&е 8а &+%е%!е J%!8к!5

    т&к !+! #-"&ка* "к&$&"т1 $&O& аK.; Pigh welding current / G-"&к!5 "#а$&:%-5 т&к.; Welder techniQue Jangle of welding torch or electrodeK / RеO%!ка !" &+%е%!* "#а$2!ка

    J0'&+ "#а$&:%&5 '&$е+к! !+! S+ект$& аK.Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF; Eeduced tra6el speed or welding current / T е%1(!т1 "к&$&"т1 $&O& а !+!

    "#а$&:%-5 т&к.; Forrect arc length / 7$а#!+1%а* +!%а 0'!.

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    Porosit5 /Пор!стостN+hat is itF / Gто Hто такоеF

    ; =orosity is the presence of ca6ities in the weld metal caused by the freeUing of gas released from theweld pool as it solidifies. Ihe porosity can taCe se6eral formsV / 7&$!"т&"т1 Sт& 'а8-е 08-$1к!# ета++е. X%! ! е т "фе$!:е"к0 ф&$ 0. 7е$#&%а:а+1%&, #&8%!к%0# # 9! к& ета++е (#а8а ":ет !%те%"!#%&'& 'а8&&3$а8а%!*, %е #"е 08-$1к! 'а8а 0" е#а т & %*т1"* %а

    е$O%&"т1 ! #-5т! # ат &"фе$0 ! 8ат#е$ е#а т. 7&$!"т&"т1 &9ет $!%! ат1 $а8+!:%-еф&$ -V

    ; distributed / $а" $е е+е%%-5,; surface breaCing pores / &$- #-O& *2!е %а е$O%&"т1 (#а,; wormhole / "#!2,

    ; crater pipes /'$0 &е $а" &+&9е%!е &$.+here can Ie o6n-F / J=е !' Bо "о "а(т!F; Ihroughout the weld beads / Aа $&т*9е%!! "#а$%-O (#.+hat -oes ca6se itF / Пр!*!"а =е1ектаF; Mbsorption of nitrogen, oYygen and hydrogen to molten weld pool trapped during solidification of the

    weld metal / 7&'+&2е%!е а8&та, к!"+&$& а ! #& &$& а # "#а$&:%0 #а%%0 8аO#а:е%%-O #&#$е * 8ат#е$ е#а%!* ета++а "#а$%&'& (#а.

    ; =oor gas shielding, as little as Z[ of air entrainment causes distributed porosity / 7$! "+а3&5

    'а8&5 8а2!те, $&%!к%е%!е +!(1 Z[ #&8 0Oа &9ет $!#е"т! к &*#+е%!$а" $е е+е%%&5 &$!"т&"т!.; BeaCs in the gas line / Tте:к! # 'а8&5 +!%!!,; Pigh gas flow rate / 7-(е%%-5 $а"O& 'а8а,; \raughts and eYcessi6e turbulence / ]к#&8%*к! ! $е#-(е%%а* т0$30+е%т%&"т1,; ^oisture of inadeQuately dried electrodes / G+а9%&"т1 %е$а#%& е$%& #-"0(е%%-O S+ект$& ,; _rease and oil of surface and filler wire / %а+!:!е 9!$ ! а"е+ %а е$O%&"т! ! %а "#а$&:%&5

    $&+&ке.

    ; >urface coating / 7е$O%&"т%-е &к$-т!*.

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    Ihe gas source should be identified and remo6ed as followsV / `"т&:%!к 'а8а &+9е% 3-т1#-*#+е% ! 0"т$а% % "+е 0 2! &3$а8& VOir entrain ent / Про"!к"о2е"!е 2о&=)'а) seal any air leaC / 'е$ ет!8а4!* &т $&%!к%е%!* #&8 0Oа,) a6oid weld pool turbulence / !83е'ат1 т0$30+е%т%&"т! "#а$&:%&5 #а%%- #& #$е * "#а$к!,) reduce eYcessi6ely high gas flow / &"+а3!т1 :$е8 е$%& #-"&к0 "т$0 'а8а,) a6oid draughts / !83е'ат1 "к#&8%*к.L5-ro7en / 0естр)кт!2"а# 3!=ро3е"!&аA!#) dry the electrode / #-"0(!т1 S+ект$& ,

    ) clean and degrease surface / &:!"т!т1 ! &3е89!$!т1 е$O%&"т!,S6r ace coatin7s / По2ер'"ост"Qе @окрQт!#) clean the Noint edges immediately before welding / %е &"$е "т#е%%& е$е "#а$к&5&:!"т!т1 "&е !%!те+1%-е к$а*Re oMa o stop / Про*!ст!тN то*к) оста"о2к! @ре=Q=)?е( с2арк! ) use run)off tag in butt Noints / "т-к&5 (,grind out the stop before continuing with the neYt electrode or depositing the subseQuent weldrun / $е9 е :е $& &+9!т1 %а%е"е%!* &"+е 0 2е'& $&O& а "#а$к! !+! $!%а+&9е%!! (#а "+е 0 2! S+ект$& & %е&3O& ! & $&:!"т!т1 т&:к0 &"та%к!

    $е - 02е5 "#а$к!.+e -er techni 6e / %е'"!ка !с@о "е"!# с2ар?!ка) progressi6ely reduce the welding current to reduce the weld pool siUe / &"те е%%&&"+а3+*т1 "#а$&:%-5 т&к, :т&3- 0 е%1(!т1 $а8 е$ "#а$&:%&5 #а%%-,) add filler JI?_K to compensate for the weld pool shrinCage / &3а#!т1 $!"а &:%-5

    ате$!а+ Jа$'&%%&) 0'а* "#а$каK # 4е+*O #&" &+%е%!* 0"а к! "#а$&:%&5 #а%%-.

    Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF

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    S a7 Tnc 6sion / U ако2ое 2к >*е"!е

    +hat is itF / Gто Hто такоеF; Eesidue of the fluY coating in >^MW, principally a deoYidation product from the reaction between the fluY, air and surface

    oYide. / 7&"+е Д]7L &"татк! (+ак&&3$а80 2е'& &к$-т!*, # $е80+1тате $еак4!! е9 0 ф+ "& +* "#а$к!, #&8 0Oа! е$O%&"т%&5 &к!"! &3$а8-#ает"* &к!"+е%!е.

    +here can Ie o6n-F / J=е !' Bо "о "а(т!F; Mt the toes of each pass of a multi)run weld / Aа '$а%!4е %а$09%&5 е$O%&"т! ка9 &'& %&'& $&O& %&'& (#а.

    +hat -oes ca6se itF / Пр!*!"а =е1ектаF; Ihe slag becomes trapped in the weld when two adNacent weld beads are deposited with inadeQuate o6erlap and a 6oid is

    formed. When the neYt layer is deposited, the entrapped slag is not melted out. >lag may also become entrapped in ca6itiesin multi)pass welds through eYcessi6e undercut in the weld toe or the une6en surface profile of the preceding weld runs. /@+ак 8а"т$е#ает # "#а$%& (#е, к&' а #е "&"е %!е "#а$%-е (#- %ак+а -#а т"* " %е &"тат&:%- е$ек$-т!е ,

    &3$а80ет"* 0"т&та. 7$! &"а9 е%!5 "+е 0 2е'& "+&*, 8а"т$*#(!5 (+ак %е $а" +а#+*ет"*, а так9е (+ак &9ет8а"т$*т1 # &+&"т! %&'&O& -O (#, :$е8 е$%& & $е8а* %!9%!5 к&%е4 !+! &3$а8-#а* %е$%0 е$O%&"т1$&ф!+* !8 $е - 02!O "#а$%-O т$а"".

    ; Welding techniQue / ]#а$&:%а* теO%&+&'!*.; Ioo high a current together with a high welding speed causing sidewall undercut which maCes slag remo6al difficult /

    `83-т&:%-5 т&к # е"те " #-"&к&5 "к&$&"т1 "#а$к! $!#& !т к & $е80 ета++а (#а 3&к&5 "те%к!, "&&т#ет"т#е%%&0 а+!т1 (+ак "та%!т"* "+&9%&.

    Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF;

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    Tnco p ete Root V6sion or Penetration / Wе@о "Q( @ро2ар кор"#2а ! !

    Xе'а"!*еск!( @р!3ар

    +hat is itF / Gто Hто такоеF; ?ncomplete root fusion is when the weld fails to fuse one side of the Noint in the root. /

    Aе &+%-5 $а$ к&$%* (#а &9ет &3$а8ат1"* # "+0:а5 е"+!, "#а$%&5 ( %е &9ет "&е !%!т1 & %0 "т&$&%0 (#а # к&$%е.; ccurs when both sides of the Noint are infused. / 7$&!"O& !т, $! &т"0т"т#!! "&е !%е%!* е9 0

    ета++& (#а ! &"%%- ета++& .

    +hat -oes ca6se itF / Пр!*!"а =е1ектаF; Mn eYcessi6ely thicC root face in a butt weld / `83-т&:%&е $!т0 +е%!е к&$%* $! "т-к& (#е.; Ioo small a root gap / ]+!(к& а+е%1к!5 8а8&$ е9 0 "#а$!#ае - ! к$& ка !.; ?ncomplete root fusion when using too low an arc energy JheatK input / Aе &+%-5 $а$ к&$%*

    (#а $! !" &+18а%!5 %е &"тат&:%&5 S%е$'!! 0'! JSффект!#%&"т! те +&5 &2%&"т!K.; Ioo small a be6el angle / ]+!(к& а+е%1к!5 0'&+ $а8 е+к! к$& &к.

    Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF; \o not use too large a root face and ensure the welding current is sufficient for the weld pool to

    penetrate fully the root / Aе !" &+18ат1 "+!(к& 3&+1(&е $!т0 +е%!е к$& к! ! &3е" е:!т1"&&т#ет"т#0 2!5 "#а$&:%-5 т&к, # 4е+*O е'& &+%&'& $&%!к%е%!* # к&$е%1 "#а$&:%&5#а%%-.; =roper siUe of torch noUUle to gi6e adeQuate access to the root and allow manipulating forpenetration and control of the weld pool / Д+* &3е" е:е%!* "&&т#ет"т#0 2е5 а%! 0+*4!5 !к&%т$&+* $&%!к%е%!* # "#а$&:%0 #а%%0, "& +& "#а$&:%&5 '&$е+к! &+9%& 3-т1"&&т#ет"т#0 2е'& $а8 е$а.

    ; Forrect root face siUe and be6el angles / а8 е$- е$O%&"т! $!т0 +е%!* ! 0'&+ $а8 е+к!к$& &к &+9%- "&&т#ет"т#ат1 $0' $0'0.

    ; MdeQuate tacCing to pre6ent the gap from closing. / G& !83е9а%!е 8а8&$а е9 0 к$& ка !"ф&$ а%%&5 8а'&тк!, е$е "#а$к&5 "#а$%-O т$03, %е&3O& ! &, "&е !%!т1 !O е9 0"&3&5 $!O#ат&:%- (#& .

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    Yack o Si-e8aan- TnterZR6n V6sion /

    Wе=остато*"ое с@ а2 е"!е ! с@ а2 е"!е Bе =)2а !каB! [2 B"о3ос о("оB 2е\+hat is itF/ Gто Hто такоеF

    ; BacC of fusion imperfections can occur when the weld metal fails. / Aе &"тат&:%&е " +а#+е%!е &9ет$&!8&5т!, к&' а $а8$0(ает"* ета++ "#а$&:%&'& (#а.

    ; Io fuse completely with the sidewall of the Noint. / 7&+%&е +а#+е%!е "т-к&'& "&е !%е%!е " 3&к&5"те%к&5.

    ; Io penetrate adeQuately the pre6ious weld bead. / 7$&%!к%е%!е $е - 02е 0 %а +а#+е%%& 0 #а+!к0"#а$%&'& (#а.

    +hat -oes ca6se itF Пр!*!"а =е1ектаF; Ioo narrow a Noint preparation / Aе ка:е"т#е%%а* & '&тка "&е !%е%!* & "#а$к0.; ?ncorrect welding parameter settings Jtoo high tra6el speed for the welding currentK / 7а$а ет$-

    %е!" $а#%&5 %а"т$&5к! "#а$к! J"+!(к& #-"&ка* "к&$&"т1 #!9е%!* +* "#а$&:%&'& т&каK.; =oor welder techniQue Jincorrect angle or manipulation of the electrode/welding gunK / 7+&Oа* теO%!ка

    "#а$2!ка J%е $а#!+1%-5 0'&+ !+! %е $а#!+1%а* а%! 0+*4!* S+ект$& & / "& "#а$&:%&5 '&$е+к&5K.; ^agnetic arc blow Jcan be caused by distortion of the magnetic field produced by the arc currentV / а'%!т%&е

    0т1е J &9ет 3-т1 #-8#а%& !"ка9е%!е а'%!т%&'& &+*, "&8 а#ае &'& т&к& 0'!KV; Eesidual magnetism in the material through using magnets for handling / Д+* $а#!+1%&'& &"02е"т#+е%!*

    &'$08&:%&)$а8'$08&:%-O & е$а4!! # ате$!а+е к&%"т$0к4!! &+9%а $!"0т"т#ат1 &"тат&:%а*а'%!т%а* !% 0к4!*.

    ; arth s magnetic field, for eYample in pipeline welding / а'%!т%&е &+е е +!, %а $! е$ $! "#а$кет$03& $& .

    ; position of the current return / 7&+&9е%!е &3$ат%&'& т&ка.; ?nsufficient cleaning of oily or scaled surfaces / Aе &"тат&:%а* &:!"тка а"+*%-O !+! а"(та3%-O

    е$O%&"те5.Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF;

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    Root concaMit5[S6ckZIack] Dn-er 8ashin7\ /

    ^о3")тостN о рат"о( сторо"Q 2а [)стро(ст2о о рат"о3о отсоса!=кост!] 3 ) !""Q( ра&BQ2 \

    +hat is itF / Gто Hто такоеF; M shallow groo6e that may occur in the root of abutt weld / е+ка* ка%а#ка, к&т&$а* &9ет#&8%!к%0т1 # к&$%е "т-к&'& "&е !%е%!*.

    +hat -oes ca6se itF / Пр!*!"а =е1ектаF; >hrinCage of the weld pool in the through)

    thicCness direction of the weld / T"а ка #"#а$&:%0 #а%%0 # "к#&8%& %а $а#+е%!!т&+2!%- (#а.

    ; ^elting of the root pass by the second pass /Rа*%!е к&$%е#&'& $&O& а #т&$- $&O& & .

    ; =oor preparation Jroot gap either too small or, insome cases, too largeK / 7+&Oа* & '&ткаJ8а8&$ е9 0 "#а$!#ае - ! к$& ка ! !+!%е &"тат&:%-5 !+!, # %ек&т&$-O "+0:а*O,

    "+!(к& 3&+1(&5 8а8&$K.; Ycessi6ely high welding speed / $е8 е$%&#-"&ка* "к&$&"т1 "#а$к!

    Lo8 can Ie aMoi-e-F / $ак Bо "о !& е атN =е1ектаF

    ; Dollow welding parameters /]+е ат1 а$а ет$а "#а$к!.

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    Zjk Z k Dield \efect

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