weld defects.pptx

7/25/2019 WELD DEFECTS.pptx

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WELDING DEFECTSByRam


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WELDING INSPECTION

Evaluation of welds to determine their

suitability for indented service.


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VISUAL INSPECTION

By usin& sim'le hand tools and &au&esto (now whether there is any e)ternalweld defects.


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STAGES OF VISUAL INSPECTION

Before weldin& $urin& weldin& After weldin&


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BEFORE WELDING

re heatin& if any

*oint +t,u' Ed&e 're'aration Ali&nment !leanin& of base metal !alibration status of +)tures if any -R if any Latest drawin& roduction document

.#


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DURING WELDING

Inter 'ass tem'erature Inter 'ass cleanin& /eldin& se0uence rocess 'arameters


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AFTER WELDING

ost weld treatment ost heatin& !leanin& Surface 0uality Internal weld 0uality $imensional accuracy

%eometrical accuracy


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FACTORS DETERMINES THEACCEPTANCE OR REJECTION

stress to which the 'art will be sub1ected

durin& service ty'e of material used tem'erature and 'ressure to which the

'arts will be stressed the environmental condition 2corrosive

non corrosive3 cost and accessibility for re'air


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WELD

DISCONTINUITY ANDWELD DEFECT $iscontinuity is some feature4 which

introduces an irre&ularity in an uniformstructure.

$efect is a s'eci+c discontinuity4 whichcan im'air the suitability of the structure.

All defects are discontinuities but4 alldiscontinuities are not defects


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Classifcatio o! "#l$$#!#cts

Bas#$ o locatio

53 surface defects

63 sub surface internal defect

Bas#$ o s%a

73 lanar defects83 Voluminar defects


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CLASSIFICATION OF DEFECTS

5. $E9E!"S INV#LVIN% INA$E-UA"E B#N$IN%:, Incom'lete fusion in fused weld. Incom'lete 'enetration.

6. 9#REI%N IN!LUSI#N:, Sla& Inclusion. #)ide +lm in fusion weld. "un&sten Inclusion.

7. %E#;E"RI! $E9E!"S:, Undercut.

E)cessive Reinforcement. Burn throu&h or e)cessive 'enetration. $istortion. Im'ro'er weld 'ro+le.

8. ;E"ALLUR%I!AL $E9E!"S. !rac(s4 %as 'orosity4 Arc stri(e4 Embitterment


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GENERAL REASONS FORDEFECTS

Lac( of (now,how.

/eldin& 'rocess characteristic.

Base metal defects or base metal com'osition4 with aninherent susce'tibility towards crac(in&.

$efective weldin& +ller metals.

*oint environment ,desi&n +t,u'

/eldin& environment 2Atmos'here4 'reheat4 inter'ass

tem'erature4 etc


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COMMON DISCONTINUITIES

!rac( Incom'lete fusion

Incom'lete 'enetration Inclusions orosity Undercut Under +ll #verla' Burn throu&h


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COMMONDISCONTINUITIES

/eld reinforcement Arc stri(e S'atter Lamination Lamellar tear $imensional defect

%eometrical defect


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CRAC'

$E9INI"I#N:

A fracture ty'e discontinuity

characteri


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TYPES OF CRAC'

surface crac( internal sub surface crac( linear crac( transverse crac( cold crac(

hot crac( delayed crac(


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TYPES OF CRAC'SBASED ON LOCATION WITH REFERENCE TOVARIOUS PARTS OF THE WELD AGAINCLASSIFIED AS

Root crac("hroat crac("oe crac(!rater crac(Under bead crac(=A> crac(Base metal crac(


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VARIOUS TYPE OFCRAC'S


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CRAC'


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CRAC'

G##(al (#asos a(#

53 resence of hydro&en

63 Im'ro'er 1oint +t

73 Restrains on the 1oints83 resence of sul'hur and 'hos'hor in base

metal

?3

;ore carbon e0uivalent in base metal@3 im'ro'er weld techni0ue

3 Im'ro'er matchin& of electrode with basemetal


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INCOMPLETE FUSION

$E9INI"I#N:

9usion not ta(en 'lace between weld metal and base metaland 2or3 between weld beads

ro'erties:#ccurs any where within weld metal and in surface also.

REAS#NS:Im'ro'er mani'ulation es'ecially in %;A/resence of sla& inclusion

Im'ro'er 1oint desi&n!ontamination on 1ob surface#)ide layers4 scales in the 1oint surfaceLow arc current


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INCOMPLETE FUSION


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INCOMPLETE FUSION


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INCOMPLETE JOINTPENETRATION

$E9INI"I#N:

"he 'enetration of molten metal does not e)tent entirelythrou&h the 1oint thic(ness where com'lete 'enetration isre0uired by s'eci+cation

R#ER"IES: Associated with &roove weldin& Location is always ad1acent to weld root

REAS#NS: Im'ro'er 1oint 're'aration

e)cess root face narrow root &a' Im'ro'er selection of electrode Im'ro'er mani'ulation Im'ro'er selection of weld 'arameter


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INCOMPLETE JOINTPENETRATON


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INCOMPLETE JOINTPENETRATION


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INCLUSIONS

$E9INI"I#N:

;etallic or non metallic 'article entra''ed insidethe weld metal

R#ER"IES:

A''earin& in the weld metal and surface of weldmetal

It is associated incom'lete fusion

"ES :

5. Sla& inclusion

6. "un&sten inclusion

7. Scale inclusion


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SLAG INCLUSION


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TUNGSTEN INCLUSION


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POROSITY

$E9INI"I#N:

It is a cavity ty'e discontinuity formed by &asentra'ment durin& solidi+cation

R#ER"IES:

Least detrimental discontinuity in structuralweldin&4 characteri


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TYPES OF POROSITY

Uniformly scattered 'orosity !luster 'orosity Linear 'orosity

i'in& 'orosity sin&le cavity ty'e elon&ated ty'e


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POROSITY

REAS#N: 'resence of contaminations resence of moisture in electrode base metal

shieldin& &as surroundin&s Im'ro'er weldin& techni0ue, lon& arc in S;A/ E)cessive hi&h travel s'eed in SA/

N#"E

If 'orosity is there 4 it indicates some 'arametersare out of control and it re0uires investi&ation.


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POROSITY


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PIPING POROSITY


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WORM HOLES

$E9INI"I#N :

Elon&ated 'orosity at surface

R#ER"IES:

It occurs in SA/ 'rocess

REAS#NS:%ranular Cu) de'th is very e)cessive

Entra''ed &as not allowed to esca'e


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WORM HOLE) ELONGATED POROSITY*


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UNDERCUT

$E9INI"I#N:

Surface discontinuity 4 occurs as linear &roove inbase metal4 ad1acent to the weld at toe or root

R#ER"IES:

$etrimental to the structure

Act as stress raisers

REAS#NS:

"ravel s'eed too hi&hIm'ro'er mani'ulation

E)cess weldin& current e)cess heat e)cessmeltin& of base metal


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UNDERCUT


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UNDERCUT


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UNDERFILL

$E9INI"I#N:

%roove li(e surface discontinuityR#ER"IES:

Associated with &roove weldin&

#ccurs in face as well root of the weld

Reduces the cross section area of the weld

REAS#NS:

"ravel s'eed too hi&h in sealin& 'assE)cessive heatin& of root 'ass durin& the second

'ass


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UNDERFILL


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UNDERFILL


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OVERLAP

$E9INI"I#N:

rotrusion of weld metal beyond the toe or root of theweld

R#ER"IES:

It is detrimental4 act as stress raisersIt occurs on the surface

It can hide some defects

It occurs in &roove weld and +llet weld

REAS#NS:Slow travel s'eed

Im'ro'er an&le

"oo Cuidity of +ller metal


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OVERLAP


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OVERLAP


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CONVE+ITY

$E9INI"I#N:

E)cessive weld metal build,u' on the face of the weld

R#ER"IES:

Associated with +llet weldIt is detrimental4 act as stress risers in fati&ue load condition

REAS#NS:

"ravel s'eed too slow

Low currentLow volt

resence of contaminations in base metal

Lac( of wettin& in weld metal


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WELD REINFORCEMENT

$E9INI"I#N:

E)cessive weld metal de'osition ro'erties: Associated with &roove weldin&

Act as stress raisers notch eDect #ccurs in face and root of &roove weld

REAS#NS:

"ravel s'eed too low

Low current Low volt resence of contaminations in base metal Lac( of wettin& of weld metal


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WELD REINFORCEMENT


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MISALIGNMENTLINEAR MISALIGNMENT ;isali&nment between two welded 'ieces such

that while their surface 'lanes are 'arallel4 theyare not in the re0uired same 'lane.

Ca,s#s

Inaccuracies in assembly 'rocedures or distortionfrom other welds

E)cessive out of CatnessF in hot rolled 'lates orsections

P(#-#tio Ade0uate chec(in& of ali&nment 'rior to weldin&

cou'led with the use of clam's and wed&es !hec( accuracy of rolled section 'rior to weldin&


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MISALIGNMENT


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MISALIGNMENT

AN%ULAR ;ISALI%N;EN" D#sc(i&tio Misali./#t 0#t"## t"o "#l$#$

&i#c#s s,c% t%at t%#i( s,(!ac# &la#sa(# ot &a(all#l o( at t%# it#$#$a.l#

Ca,s#s a$ &(#-#tio Same as for linear misali&nment


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SPATTERS

$E9INI"I#N: ;etal 'articles stic( to the base metalad1acent to the weld metal

R#ER"IES:

Lar&e &lobules of s'atters may have suGcientheat to cause heat aDected


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SPATTERS


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ARC STRI'ES

$E9INI"I#N: Locali


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ARC STRI'E

EN ISO 1234 6774


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EN ISO 1234567748,alit9 l#-#l !o( i/(!#ctios

"his International Standard 'rovides 0ualitylevels of im'erfections in fusion,welded 1oints

all ty'es of steel4 nic(el4 titanium and their alloys. It a''lies to material thic(ness above H4? mm. It covers fully 'enetrated butt welds and all +llet

welds "hree 0uality levels are &iven in order to 'ermit

a''lication to a wide ran&e of welded fabrication4

desi&nated by symbols B4 ! and $. diDerent 0uality levels are a''lied to individual

welded 1oints in the same 'roduct or com'onent.

EN ISO 1234 6774


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"he 0uality level necessary in each caseshould be de+ned by

5. the a''lication standard6. the res'onsible desi&ner in con1unction

with the manufacturer4

7. user andor other 'arties concerned.

EN ISO 1234 6774


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"he choice of 0uality level for any a''licationshould ta(e account of

desi&n considerations4 subse0uent 'rocessin& 2e.&. surfacin&34 mode of stressin& 2e.&. static4 dynamic34 service conditions 2e.&. tem'erature4

Environment3

conse0uences of failure. Economic factors arealso im'ortant and should include not only the cost of weldin& but also of ins'ection4 test

and re'air.

EN ISO 1234 6774


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Quality level

$escri'tion of the 0uality of a weld on thebasis of ty'e4 si


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Short imperfections

In cases when the weld is 5HH mm lon& or lon&er4im'erfections are considered to be short,im'erfections if4 in the 5HH mm which contains the

&reatest number of im'erfections4 their total len&this less than 6? mm in cases when the weld is lessthan 5HH mm lon&4 im'erfections are considered tobe short im'erfections if their total len&th is less than6? of the len&th of the weld

Systematic imperfection Im'erfections that are re'eatedly distributed in the

weld over the weld len&th to be e)amined4 the si


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Ass#ss/#t o! i/(!#ctios Limits for im'erfections are &iven in "able

If4 for the detection of im'erfections4 micro,

e)amination is used4 only those im'erfections shallbe considered which can be detected with ama)imum of tenfold ma&ni+cation. E)cluded fromthis are micro lac( of fusion.

Systematic im'erfections are only 'ermitted in0uality level $4 'rovided other re0uirements of

"able 5 are ful+lled.

EN ISO 1234 6774


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Ass#ss/#t o! i/(!#ctios A welded 1oint should usually be assessed

se'arately for each individual ty'e of im'erfection.$iDerent ty'es of im'erfection occurrin& at any

cross,section of the 1oint need s'ecial consideration."he limits for multi'le im'erfections are onlya''licable for cases where the re0uirements for asin&le im'erfection are not e)ceeded.

Any two ad1acent im'erfections se'arated by adistance smaller than the ma1or dimension of thesmaller im'erfection shall be considered as a sin&leim'erfection

EN ISO 1234 6774


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a -nominal throat thickness of the llet weld (see alsoISO 2553)

b-width of weld reinforcement

d -diameter of gas pore

h -height or width of imperfectionl -length of imperfection in longitudinal direction of

the weld

s -nominal utt weld thickness (see also ISO 2553)

t -wall or plate thickness (nominal si!e)! -leg length of a llet weld (see also ISO 2553)

K an&le of weld toe

an&le of an&ular misali&nment


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ACCEPTANCE CRITERIAI/(!

#ctio$#si.atio

R#/a(:s t

// Limits for imperfections for quality levels$ ! B

S,(!ac# &o(#

Ma;i/,/$i/#sioo! a si.l#&o(# !o(< 0,tt"#l$s< fll#t"#l$s

< 0,tt"#l$s

7=1 to >7=1 to >

M 7

M 7

d 0,3sd 0,3a

d "#3s# utma$% 3mm

Not(/itt#$

d "#2 s#ut ma$% 2mm

d "#2 a#

Not(/itt#$

Not(/itt#$

Not


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//

Limits for imperfections for quality levels

$ ! B

Incom'lete root'enetration

#nly forsin&le sidebutt welds

H4?Shortim'erfections:h & "#2 t#ut ma$%2 mm

Not'ermitted

Not 'ermitted


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s

t//


$ ! B

!ontinuousundercutIntermittentundercut

Smoothtransition isre0uired.

"his isnotre&ardedas asystematicim'erfection

H4? to 7

M 7

Shortim'erfections:h &"#2 t

h & "#2 t#ut ma$%' mm

Shortim'erfections:

h & "#' t

h & "#' t#but ma). H4?mm

Not 'ermitted

h& "#"5 t#but ma). H4?mm


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

E)cessweldmetal2butt weld3

E)cessiveconve)ity2+lletweld3

Smoothtransitionisre0uired.

H4?

H4?

h O5mm PH46? 4but ma).5H mm

h O5mm PH46? 4but ma).? mm

h O5 mm PH45? 4but ma). mm

h O5 mm PH45? 4but ma). 8mm

Not

h O5 mm P H454But ma). ? mm

h O5 mm P H454but ma). 7 mm


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

E)cessiveasymmetry of+llet weld2e)cessiveune0ualle&Len&th3

In caseswhere anasymmetric +lletweld hasnot been'rescribed

H4?h &2 mm "#2 a

h & 2 mm "#'5 a

h & '#5 mm "#'5 a


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

InsuGcientthroatthic(ness

Nota''licableto'rocesseswith 'roofof&reaterde'th of'enetration

H4? to 7

M 7

Shortim'erfections:

h &"#2mm "#' a

h & "#3mm "#' a#

Shortim'erfections

h&"#2 mm

h & "#3 mm "#' a#but ma). 5

Not 'ermitted

Not 'ermitted


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

E)cessive

throatthic(ness

"he actual

throatthic(nessof the +lletweld istoo lar&e.

H4?

Unlimited

.h O 5 mm

P H46 a4but ma). 8mm

h O 5 mm PH45? a4but ma). 7 mm


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

S'atter

H4?

Acceptance

depends onapplication

e.g.

material,

Corrosion

protection

Acceptance

depends onapplication

e.g. material,

Corrosion

protection

Acceptance depends

on application

e.g. material,

Corrosion protection


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ACCEPTANCE CRITERIA

I/(!#ctio$#si.atio

R#/a(:s t//


$ ! B

Lac( offusion

;icrolac( offusion

,,,,,,,

#nlydetectableby microe)amination

H4?

H4?

Not(/itt#$

(/itt#$

Not(/itt#$

(/itt#$

Not(/itt#$

(/itt#$


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"=ANQ #U

weld defects.pptx

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