inspectors course (presentation)-04-2012.ppt

8/18/2019 Inspectors Course (Presentation)-04-2012.ppt

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Inspecting Hot-DipGalvanized Steel

American Galvanizers Association

6881 S Holly Circle Suite #18

Centennial! C" 811aga$galvanizeit%org

&&&%galvanizeit%org

1-8-H"'-S()C

Protecting Steel for Generations

mailto:[email protected]://www.galvanizeit.org/http://www.galvanizeit.org/mailto:[email protected]


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08/04/16 © 2005 American Galvanizers Association

Protecting Steel for Generations2

AGA Inspection Course

• Designed to educate t*e Inspector!

)ngineers and Speci+iers

• 'opics Covered

– Galvanizing Basics, a process

overview

– ASTM Galvanizing Specifications

• e!"irements• #eas"rement $ec%ni!"es

– Rejectable Coating Defects


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&

,*at is Galvanizing

• Applying a

corrosion

resistant zinc

coating .ydipping

+a.ricated

steel into a

.at* o+ moltenzinc%


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations

4

,*y Galvanize

Corrosion (rotection

• Cost )++ective

• Dura.le

• Complete Coverage! inside and out

• /aintenance-+ree Service 0i+e


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5

Hot-Dip Galvanizing (rocess

Sur+ace (reparation

• Sur+ace (reparation – Degreasing

• $'(icall' an al)aline sol"tion

• emoves *irt+ oil+ an* grease

– Pickling • S"lf"ric or ,'*roc%loric aci*

• emoves mill scale an*o-i*ation

– l!"ing • .ig%tl' aci*ic zinc c%lori*e an*

ammoni"m c%lori*e sol"tion• leans steel an* (rovi*e

(rotective la'er (rior togalvanizing


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6

Hot-Dip Galvanizing (rocess

Galvanizing

• Galvanizing 2ettle

– #inc

• AS$# 6 or 60

8 3 n

• 8&5 o 7445 o

– Minor Allo$ing

%le&ents

• Al"min"m

• ism"t%

• $in

• .ea*

• 9ic)el


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:

(ost Galvanizing "perations

• 3uenc*ing 4optional5

– Cooling

– Passivation 'C(ro&ating)

• inis*ing

– Painting

– S!rface Profiling


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8

'*e Galvanized Coating


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Complete Coverage


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10

"t*er 'ypes o+

Corrosion (revention

• (aints

• ,eat*ering Steel

• Stainless Steel

• Aluminum• 'ar7Asp*alt

• "il7Grease

• (olymer Coatings

• (lating

• Sacri+icial Anodes• Impressed

Current


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inc Coatings

• )lectroplated

• Continuous Galvanized

• inc (aint

• /etallized

• /ec*anical Coating

• 9atc* Hot-Dip Galvanized


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)lectroplated inc

• Coating applied .y su.mersion inelectrolytic .at*%

• Coating is typically pure zinc 4nointermetallics5! tig*tly ad*erent tosu.strate and very ductile%

• Coating t*ic:nesses ranging up to 1 mil%

• ;sed indoors or in mild environments%

• /ost commonly used on s*eet and stripor +or small parts li:e scre&s and ot*erlig*t +asteners%


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Protecting Steel for Generations1&

Continuously Galvanized S*eet

• Coating applied .y immersion in molten zinc%• Almost entirely unalloyed zinc ma:ing it very

ductile! most


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inc (aint

• 9arrier coating applied to clean steel%• "nly sometimes a++ords cat*odic

protection%

• Commonly used to repair damagedgalvanizing%

• 'ypically does not eceed B mils%

• )asily applied to a variety o+ product

types and designs *o&ever! t*e coatingis typically limited to eteriors .ecauseo+ t*e met*od o+ application%


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/etallized

• e>uires special e>uipment and trainingto apply e++ectively%

• Cat*odic and .arrier protection%

• Can .e applied in coating t*ic:nessessimilar to *ot-dip galvanized%

• Coating density is less t*an t*e *ot-dip

galvanized coating density%

• Accepta.le met*od o+ repairing *ot-dip

galvanized%


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inc Coatings

atc% ,ot;S$A$=


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Protecting Steel for Generations1:

AS'/ Standards +or Galvanizing

• AS'/ A1E7A1E/ – Stan*ar* Specification for #inc '+otDip

Galvanize*) Coatings on -ron an* Steel

Pro*!cts

• AS'/ A1?E7A1?E/

– Stan*ar* Specification for #inc Coating

'+otDip) on -ron an* Steel +ar*ware

• AS'/ A@6@7A@6@/ – Stan*ar* Specification for #incCoate*

'Galvanize*) Steel Bars for Concrete

Reinforce&ent


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Supporting AS'/ Speci+ications

• AS'/ A1BE7A1BE/ – Practice for Safeg!ar*ing Against

%&brittle&ent of +otDip Galvanize*

Str!ct!ral Steel Pro*!cts an* Proce*!re for

Detecting %&brittle&ent

• AS'/ AE8B7AE8B/

– Practice for Safeg!ar*ing Against .arpage

an* Distortion D!ring +otDip Galvanizing

of Steel Asse&blies


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Supporting AS'/ Speci+ications

• AS'/ AE8?7AE8?/ – Practice for Provi*ing +ig( /!alit$ #inc

Coatings '+otDip)

• AS'/ A@8

– Practice for Repair of Da&age* an* 0ncoate*

Areas of +otDip Galvanize* Coatings

• AS'/ D6E86

– Practice for Preparation of #inc '+otDipGalvanize*) Coate* -ron an* Steel Pro*!ct

an* +ar*ware S!rfaces for Painting


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"t*er Galvanizing Standards

• CAF7CSA-G16B-/


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Application o+ inc onto Steel

• /ost commonly speci+ied .atc* *ot-dip coating type is AS'/ A1E%

• Covers many designs and product

types%


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AS'/ A1E

• (roducts Structural Steel and(late Strip and 9ar (ipe and'u.ing ,ire ein+orcing 9ar

• 9ot* Single (arts and Assem.lies – Asse&blies can be &a*e of several

pro*!ct t$pes, enco&passing &an$*ifferent &aterial categories an*&ini&!& re2!ire* coating gra*es3

Assem.ly &it* /ultiple Coating


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2&

Assem.ly &it* /ultiple Coating

'*ic:ness e>uirements


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24

• Design and +a.rication areresponsi.ility o+ designer and+a.ricator

• A1BE! AE8B and AE8? provideguidance

• Castings s*all .e properly *eat-treated as in AS'/ AB@

• inc (er AS'/ 96 or 9


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AS'/ A1E e>uirements

• Coating '*ic:ness material categor'an* steel t%ic)ness

• inis* contin"o"s+ smoot%+ "niform

• Appearance free from "ncoate* areas+?listers+ fl"- *e(osits an* gross *rossincl"sions – No heavy zinc deposits that interfere with

intended use.

• Ad*erence s%o"l* ?e tig%tl' a*%erentt%ro"g% all e-(ecte* "ses of article


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Coating '*ic:ness

• Coating t*ic:ness grade is microns

• ? microns is 1 mil

• Coating t*ic:ness is .y material type

and t*ic:ness! even on assem.lies• /inimum .ut no maimum

• '*ic:er coatings can .e re>uested .y

t*e purc*aser • Structural tu.ing is still tu.ing


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2:

Coating '*ic:ness AS'/ A1E

#aterial ategor' All S(ecimens $este*Steel $%ic)ness ange 7#eas"re*+ in@ 7mm

1/16 71@6 1/16 to 1/8 71@6 to &@2 1/8 to &/16 7&@2 to 4@8&/16 to 1/4 74@8 to

6@4 ≥1/4 7≥6@4

Str"ct"ral S%a(es an*Plate

45 65 :5 :5 100

Stri( an* ar 45 65 :5 :5 100

Pi(e an* $"?ing 45 45 :5 :5 :5

Bire &5 50 60 65 80

einforcing ar @@@ @@@ @@@ @@@ 100


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28

Coating '*ic:ness Conversion


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2

AS'/ A1E 'a.le 1 and 'a.le

=-am(leC 1/16D t%ic) steel ?ar

oating Gra*e


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Protecting Steel for Generations&0

inis*

• Continuous no ?rea)s or %oles in t%ecoating

• easona.ly Smoot* relative term+ minorro"g%ness t%at *oes not interfere Eit% t%e

inten*e* "se or ro"g%ness t%at is relate* tot%e receive* con*ition of t%e steel isacce(ta?le

• ;ni+orm as t%e steel c%emistr' an*section t%ic)ness (ermits

• Intended ;se – t%e finis% of t%e coating Eillnot interfere Eit% its inten*e* "se@


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Intended ;se

• '*e galvanized coating s*ould not*ave sur+ace imper+ections t*at&ould impair or inter+ere &it* t*e

intended use o+ t*at product% – -&perfections can incl!*e l!&ps, projections, glob!les, or (eav$*eposits of zinc3

• ,an*rails• #oving Parts

• Articles to ?e (ainte* after galvanization


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Appearance

• ;pon s*ipment to t*e customer!galvanized articles s*ould .e +ree +rom

– 0ncoate* Areas

– Blisters – l!" Deposits

– Gross Dross -ncl!sion

– %"cess zinc t(at interferes wit( t(einten*e* !se of t(e pro*!ct


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Protecting Steel for Generations&&

Appearance

• Conditions allo&ed – D!ll coating

– C(ain, wire &arks

– S&all (oles 4 5 inc(, fille* wit( zinc

– Bot( brig(t an* *!ll coating

– Ski&&ings on s!rface


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Ad*erence

• '*e zinc coating &ill &it*stand*andling consistent &it* t*e nature

and t*ic:ness o+ t*e coating and

normal use o+ t*e article &it*outpeeling or +la:ing

– -n general t(e zinc coating applie* to

article covere* b$ t(is specificationare too (eav$ to per&it severe

ben*ing wit(o!t peeling or flaking3


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Special Instructions

• S*ould .e stated on t*e purc*aseorder%

• )amples

– 6ot /!enc(ing if Painting

– Re&oving To!g( S!rface

Conta&inant b$ Grin*ing

– An$ Special Re2!ests Agree* 0ponb$ Bot( Parties


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&6

Galvanizers esponsi.ility

• It is t*e responsi.ility o+ t*e galvanizer toensure compliance &it* t*is speci+ication%

• '*e material s*all .e inspected at t*e

galvanizers plant prior to s*ipment%

• /aterials reJected +or reasons ot*er t*anem.rittlement may .e repaired according

to AS'/ A@8 or stripped! regalvanized!and resu.mitted +or con+ormity to t*isspeci+ication%


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&:

AS'/ A1?E Hard&are

• Applies to *ard&are items t*at &ill.e centri+uged! spun or ot*er&ise

*andled to remove ecessive +ree

zinc% – Castings

– Rolle*, Presse* an* orge* Articles

– asteners – Miscellaneo!s T(rea*e* 7bjects


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&8

/aterials /anu+acture

• inc metal per AS'/ 96 or 9


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&

A1?E e>uirements

• Coating '*ic:ness7,eig*t• '*readed Articles areas Eit% t%rea*s

are not s"?Fect to t%e coating t%ic)ness

re!"irement• inis* and Appearance

• )m.rittlement %ig% tensile strengt%fasteners an* castings can ?e s"?Fect to

em?rittlement• Ad*erence

AS'/ A1?E 'a.le 1


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40

AS'/ A1?E 'a.le 1

Coating '*ic:ness7,eig*t


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41

'*readed Articles

• '*e zinc coating on t*reads s*ouldnot .e cut! rolled! or su.Ject to

+inis*ing tool operations%

– -n or*er to &eet overtapping

allowances, tappe* (oles or t(e

tapping of t(e t(rea*s of n!ts after

galvanizing is per&itte*3


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42

inis* and Appearance

• ;pon s*ipment to t*e customer!galvanized articles s*ould .e +ree

+rom

– 0ncoate* Areas – Blisters

– l!" Deposits

– Gross Dross -ncl!sion – %"cess zinc t(at interferes wit( t(e

inten*e* !se of t(e pro*!ct


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4&

)m.rittlement

• Can .e caused .y cold &or:ing!degree depends on t*ese +actors

– Steel t$pe 'strengt( level, aging

c(aracteristics) – T(ickness

– A&o!nt of col* working

– Galvanizing process


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44

Hig* 3uality Coatings

• Select steel composition to ensurea *ig* >uality coating

– Carbon 4 839: ;

– P(osp(or!s 4 838< ; – Manganese 4 =3> ;

– Silicon 4 838> ; or

– 83=: ; 4 Silicon 4 8399 ;


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45

Ad*erence

• Coating s*ould ad*ere tig*tly tot*e steel t*roug*out all reasona.leactivities%

• I+ articles covered .y galvanizedcoatings are .ent or +a.ricated tosuc* a degree t*at +la:ing orcrac:ing occurs! t*is is not acause +or reJection%


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46

Single (roduct Spec! AS'/ A@6@

• AS'/ A1E and AS'/ A1?Edescri.es a *ot-dip galvanizing

process t*at applies zinc to a

variety o+ di++erent steel products%

• AS'/ A@6@ is a speci+ication t*at

descri.es only one uni>ueproduct rein+orcing steel 4re.ar5%


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4:

AS'/ A@6@

• Standard speci+ically +or steelrein+orcement! smoot* or de+ormed%

• Includes a c*romate >uenc* step toprevent a reaction .et&een t*egalvanized .ars and +res* (ortlandcement%

• Does not include rein+orcing &ires%


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48

A@6@ e>uirements

• Identity $%e galvanizer is res(onsi?le forconsistent material trac)ing if necessar'@

• Coating '*ic:ness

• C*romating $o (revent reaction ?etEeenPortlan* ement an* recentl' galvanize*

material%

• inis* and Ad*erence

• 9end Diameters la)ing an* crac)ing

*"e to fa?rication are not reFecta?le@


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4

Identity

• '*e galvanizer is responsi.le +ormaintaining t*e identity o+ t*e

re.ar t*roug* t*e galvanizing

process%

• Direct s*ipment to t*e Jo.-site may

.e necessary and identity must .epreserved during t*is s*ipment%

A@6@ 'a.le 1


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50

A@6@ 'a.le 1

Coating '*ic:ness7,eig*t

C* i


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51

C*romating

• All galvanized re.ar is re>uired to.e c*romate treated%

• C*romate solution must .e %=

• Common practice is to ta:e

eception to t*is speci+ication

re>uirement%

i i *


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52

inis*

• Fo .are spots• ree o+ .listers! +lu spots or

inclusions! dross and acid or .lac:

spots%• 9ars t*at stic: toget*er &ill .e

reJected%

•'ears or s*arp spi:es &*ic* ma:et*e .ars *azardous to *andle arecause +or reJection

Ad*


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5&

Ad*erence

• '*e coating s*all .e ad*erent so itcannot .e removed .y any

reasona.le process o+ *andling or

erection%

A@6@ 'a.le


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54

A@6@ 'a.le

/inimum inis*ed 9end Diameters

9 di


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55

9ending

• Damage done to t*e coating &*en

.ending is done a+ter galvanizing is

not a cause +or reJection and may .e

repaired%

– Cracking

– laking

I ti ' * i


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56

Inspection 'ec*ni>ues

• Coating '*ic:ness7,eig*t – Magnetic Coating Ga!ges

– 7ptical Microscop$

– .eig(Galvanize.eig( – .eig(Strip.eig(

• inis* and Appearance –

?is!al -nspection• Ad*erence – Sto!t @nife

I ti ' * i


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5:

Inspection 'ec*ni>ues

• )m.rittlement – Si&ilar Ben* Ra*i!s

– S(arp Blow

– Steel Angle

• C*romating

– Spot test

• 9ending

– Table

Keri+ying Coating '*ic:ness7,eig*t


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58

y g g g

/easurement 'ec*ni>ues

Coating '*ic:ness• /agnetic

'*ic:ness

Gauges

– 6on*estr!ctive

• "ptical

/icroscopy

– Destr!ctive

Coating ,eig*t• ,eig*-Galvanize-

,eig*

– 6on*estr!ctive

• ,eig*-Strip-

,eig*

– Destr!ctive

/ ti '*i : G


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5

/agnetic '*ic:ness Gauges

• (ull-"++ Gauge – Pencil st$le

• S(ring;loa*e* magnet

–


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60


• /agnetic 9alanceGauge

– Banana st$le

• S(ring;loa*e*

magnet an* *ialga"ge

– Acc"rac' 103

– lat s"rfaces onl'

– re!"ent

cali?ration• Still >se*

/ ti '*i : G


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61


• )lectronic Gauge – Man$ St$les

• $em(erat"re

com(ensate*

magnetictrans*"cer

– atter' (oEere*

– Acc"rac' 53

– =as' to rea*

• #ost common

AS'/ )E@6Meas!ring Coating T(ickness b$ Magnetic iel* or


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62

Meas!ring Coating T(ickness b$ Magneticiel* or

%**$C!rrent '%lectro&agnetic) %"a&ination Met(o*s

• /easurements on large articless*ould .e made at least B inc*es

+rom t*e edge to avoid edge e++ects%

• /easurement readings s*ould .e as

&idely dispersed as possi.le%

educing )rror &*en using


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6&

g g

/agnetic Gauge Instruments

• ecali.rate +re>uently! using non-magnetic+ilm standards or s*ims%

• eadings s*ould not .e ta:en near an edge!*ole or inside corner%

• eadings ta:en on curved sur+aces s*ould.e avoided i+ possi.le%• 'est points s*ould .e on Lregular areasM o+

t*e coating%

• 'a:e at least +ive readings to o.tain a good!LtrueM value &*ic* is representative o+ t*e&*ole sample%

Cali.ration (ointers


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64

Cali.ration (ointers

• /agnetic t*ic:ness gauges must.e properly cali.rated +or accurate

readings%

– Calibration is *one !sing non &agnetic stan*ar*s of known

t(icknesses3

– @nown stan*ar*s of bot( above an*

below t(e e"pecte* t(ickness val!es

s(o!l* be !se* for calibration3

/a:ing /agnetic


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65

g g'*ic:ness /easurements

• A minimum o+ +ive values s*ould .eta:en +or eac* specimen%

• '*e average o+ t*ese specimenvalues s*ould not .e less t*an one

t*ic:ness grade lo&er t*an t*e

re>uired coating t*ic:ness given .yt*e standard%

Coating '*ic:ness /easurement


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66

g"ptical /icroscopy! AS'/ 9B8@

•


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6:

g g

,eig*-Galvanize-,eig*

• Step1 ,eig*t A+terCleaning 4pre-galvanize5

• Step ,eig*t A+ter

Cooling 4post-galvanize5

• Determine Sur+ace Area+or Coating '*ic:ness

Calculation

• /et*od Does F"'

Account +or eacted Iron• ;nderestimates Coating

,eig*t .y up to 1=

Coating ,eig*t /easurement


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68

g g

,eig*ing-Strip-,eig*! AS'/ A


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6

Inspecting inis*

• Kisual Inspection – 0n&agnifie* or nake* e$e

– 7bserve s!rface con*itions, bot(

insi*e an* o!t of fabrication 't!bes) – C(eck contact points, i3e3 wel*s,

j!nctions, bent areas

Inspecting Appearance


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:0


• Kisual Inspection – 0n&agnifie* or nake* e$e

– 7bserve s!rface con*itions, bot(

insi*e an* o!t of fabrication 't!bes) – C(eck contact points, i3e3 wel*s,

j!nctions, bent areas

9are Spots


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:1

- Fot Accepta.le

• Inade>uate Sur+ace

(reparation

• ,elding Slag

• Sand )m.edded in

Castings

• )cess Aluminum in

inc 9at*

•Articles in Contact

• C*ain and ,ire

/ar:s

9are Spots


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:2

- Fot Accepta.le

;ncoated Areas


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:&

- Fot Accepta.le

lu Inclusions


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:4

- Fot Accepta.le

• ,etGalvanizing

• Cause 9are

Spots• Sur+ace De+ect

• Clean and

epair

S:immings on Sur+ace


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:5

- Accepta.le

S:immings versus lu


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:6

S:immings versus lu

• S:immings – Galvanize*

– Aest(etic Defect

• lu – 0ngalvanize*

– Rejectable Defect

,elding Spatter


77/154


::

- Fot Accepta.le

Sand )m.edded in Castings


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:8

- Fot Accepta.le



79/154


:


• (re+a.ricated Holes – +oles =9 inc( or larger s(o!l* be clean

an* wit( &ini&al zinc *eposit3

• /ar:s +rom Handling )>uipment – Marks left b$ (an*ling e2!ip&ent are not

ca!se for rejection, !nless t(ese &arks(ave e"pose* t(e base steel &etal3

– Pieces s(o!l* be (an*le* an*

positione* appropriatel$ *!ring coolingto prevent t(e freezing toget(er ofarticles3

C*ain and ,ire /ar:s


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80

- (ossi.ly Accepta.le

Drainage Spi:es


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations 81

- Fot Accepta.le

Clogged '*reads


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- Fot Accepta.le

Clogged Holes


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations 8&

- Accepta.le

"ide 0inesA .l


84/154


- Accepta.le

'ouc* /ar:sF t A t .l


85/154


- Fot Accepta.le

Articles in ContactF t A t .l


86/154


- Fot Accepta.le

Sur+ace ContaminantsF t A t .l


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations 8:

- Fot Accepta.le

is* 9oningA t .l


88/154


- Accepta.le

)cess Aluminum in 9at*F t A t .l


89/154


- Fot Accepta.le

Delamination( i.l A t .l


90/154



la:ing 7 DelaminationF t A t .l


91/154


- Fot Accepta.le

Dross( i.l A t .l


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Dross InclusionsA t .l


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations &

- Accepta.le

• Small (imples inCoating

• Iron7inc (articles

• 0arge Dross(articles emovedand epaired

• Small DrossInclusions Allo&ed

StriationsAccepta.le


94/154


- Accepta.le

StriationsAccepta.le


95/154


- Accepta.le

9lasting DamageAccepta.le


96/154


- Accepta.le

9leedingAccepta.le


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08/04/16 © 2005 American Galvanizers AssociationProtecting Steel for Generations :

- Accepta.le

9leedingAccepta.le


98/154


- Accepta.le

9leedingAccepta.le


99/154


- Accepta.le

,eeping ,elds


100/154


p g

• Incomplete &elds and unsealedareas less t*an E7EM can entrap

cleaning solutions t*at &ill .leed

out staining to surrounding areas%

oug* Sur+aces


101/154


g

• Galvanizing &ill s*o& t*e sur+aceconditions o+ t*e underlying steel%

oug* Sur+aceAccepta.le


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102

- Accepta.le

Steel Sur+ace ConditionAccepta.le


103/154


10&

- Accepta.le

uns(ossi.ly Accepta.le


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104


9lo&outs- Fot Accepta.le


105/154


105

- Fot Accepta.le

Distortion- (ossi.ly Accepta.le


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106


,et Storage Stain- Fot Accepta.le


107/154


10:

- Fot Accepta.le

,et Storage Stain- Fot Accepta.le


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108

- Fot Accepta.le

• Koluminous! &*ite!po&dery corrosion

products resulting

+rom improper

material *andlingand storage

practices%

,et Storage Stain


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10

• Suscepti.le )nvironments – +!&i*

– Stagnant

– .aterfront – Marine

– -n*!strial

– 7!t*oor storage

,et Storage Stain


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• Suscepti.le (roducts – 6ewl$ Galvanize* Material

– Tig(tl$ packe* articles

– Poorl$ ventilate* – Stacke* articles like s(eet, plates,

angles, bar an* pipe

,et Storage Stain


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• (revention – Galvanize* ite&s s(o!l* be clean an*

free of fl!"3

–-te&s s(o!l* be store* !n*er cover in*r$, well ventilate* areas3

– -f stacking is !navoi*able, articles

s(o!l* be raise* fro& t(e gro!n* an*

separate* wit( strip spacers to provi*efree &oving air to all s!rfaces3

,et Storage Stain


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• Impact on Coating 0i+e – ig(t

– Me*i!&

– +eav$ • 'ypically only scenarios o+ *eavy &et

storage stain produce apprecia.le

zinc loss t*at can negatively a++ectcoating per+ormance%

,et Storage Stain! 0ig*t- Accepta.le


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11&

Accepta.le

• /ild! lig*t stainingin most cases does

not need to .e

cleaned and &ill

&eat*er naturally tomatc* una++ected

areas%

,et Storage Stain! /edium- Accepta.le


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114

Accepta.le

• /ost parts &it* amedium layer o+

&et storage stain

can .e cleaned

and t*en put intoservice%

,et Storage Stain! Heavy- Fot Accepta.le


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115

Fot Accepta.le

• Some parts &it**eavy &et storage

staining can .e

cleaned! .ut most

must .e strippedand regalvanized

.e+ore .eing put

into service%

,et Storage Stain


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116

• ;npreventa.le Situations – -n certain environ&ents *!ring

seasons of e"tre&e (!&i*it$ an*

rainfall, wet storage staining is

!navoi*able3

– Most lig(t storage staining will

weat(er to be in*isting!is(able fro&

!naffecte* areas3

,et Storage Stain


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Protecting Steel for Generations11:

• Fatural ,eat*ering – .(en an galvanize* &etal s!bject to

wet storage stain is place* intoservice, e"pos!re to free flowing air

as well as wetting an* *r$ing c$clewill pro*!ce a la$er of zinc carbonateknown as t(e zinc patina3

– or&ation of t(e zinc patina pro*!ces

a coating t(at is !nifor& inappearance3

,et Storage Stain


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118

,eat*ered ,et Storage Stain


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11

,et Storage Staining


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• Galvanizers esponsi.ility – Responsible for proper storage w(ile

on (is lot3

• (urc*asers esponsi.ility

– Responsible for proper storage once

t(e &aterial (as left t(e galvanizers

lot3

Kisual Inspection S*iny vs% Dull- Accepta.le


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121

Accepta.le

Dull and S*iny- Accepta.le


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122

p

Gray Coatings- Accepta.le


123/154



12&

p



124/154



124

p



125/154



125

p

Grey Coatings- Accepta.le


126/154



126

p

easons +or Di++erent Appearances


127/154



12:

• Smoot* versusoug*

• S*iny versus Dull

• Steel C*emistry -

Silicon and

(*osp*orus

• Accelerated

Coating Gro&t*

Silicons In+luence on Galvanizing


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128

• Can t*e coating get too t*ic:

• ,*at are t*e negatives o+

ecessively t*ic: coating

eactive Steel /icrograp*


129/154



12

Accelerated Gro&t*


130/154



1&0

Typical Zinc-IronAlloy Layers

IrregularIrregular Zinc-IronZinc-Iron

Alloy LayersAlloy Layers

Coating '*ic:ness '*e Sandelin Curve


131/154



1&1

• '&o regions

o+ increased

coating &eig*t

due to = mass

Silicon

• (*osp*orus

adds to

Silicon )++ects

( r e l a t i v e )

(*osp*orus


132/154



1&2

• Castings andCold-rolled7Cold-

,or:ed /aterials

• Impurity in Steel

• )++ects 'ypical

– Gra$ Areas

– Striations

'esting Ad*erenceStout 2ni+e 'est


133/154



1&&

• Ad*esion test Stout :ni+e

• (us* do&n point o+stout :ni+e

• Fot at edges orcorners

• Coating must not+la:e o++

• Fo paring or&*ittling &it* :ni+e

Inspecting )m.rittlement


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1&4

• (arts suspected o+ em.rittlements*all .e tested per AS'/ A1BE%

– Si&ilar Ben* Ra*i!s

– S(arp Blow – Steel Angle

C*romating


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1&5

• '*e presence o+ *eavalentc*romium on galvanized sur+acesis determined .y spot testing usingAS'/ (ractice 91

• '*e test involved dropping leadacetate on t*e sur+ace! &aiting ?seconds! and .lotting it gently%

• '*e presence o+ a dar: deposit or.lac: stain is a negative test%

Sampling


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1&6

• 1= inspection o+ every galvanizedarticle is time consuming%

• Sampling protocol *as .een outlinedin t*e AS'/ speci+ications%

Sampling 2ey ,ords


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1&:

0ot "nit of (ro*"ction or s%i(ment fromE%ic% a sam(le is ta)en for testing@

Sample A collection of in*ivi*"al "nits of(ro*"ct from a single lot@

'est Article an in*ivi*"al "nit of (ro*"ctt%at is a mem?er of t%e sam(le@

Specimen t%e s"rface of an in*ivi*"al testarticle or a (ortion of a test article E%ic% is

a mem?er of a lot or a mem?er of a sam(lere(resenting t%at lot@

Sampling


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1&8

• N 16 in# 41! mm#5• andomly selected test articles to .e

used as individual specimens

Sampling


139/154



1&

• O 16 in# 41! mm#5

• )ac* sample is divided into t*reespecimens

/inimum Fum.er o+ Specimens


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140

• or .ot* AS'/A1E and A1?Et*e +ollo&ingta.le is used to

select t*eminimum # o+specimens to .eselected +or

sampling +rom agiven lot size

# o+ (iecesin 0ot # o+Specimens

& or less All

4 to 500 &

501 to 1200 5

1201 to &200 8

&201 to 10+000 1&

10+001H 20

AS'/ A@6@ Fum.er o+ 'ests


141/154



141

/agnetic '*ic:nessE Samples per lot

? "r moremeasurements

per sample1? /easurements!

at t*e minimum!comprise t*e

average

Stripping and ,eig*ingE Samples per lot

/icroscopy /et*od

? Samples per lot

B /easurements persample

/easurements! atminimum! compriset*e average

Galvanized CoatingInspection esults


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142

• Acceptance – Meet all t(e specifications re2!ire&ents3

• epair

– Meets &ost of t(e specifications

re2!ire&ents3 0nacceptable areas can berepaire* per t(e specification3

• eJection

– Defect areas are too large or are inaccessible

to repair3 Ma$ be strippe*, regalvanize*, an*

res!b&itte* for inspection3

Fon-con+ormities int*e Galvanized Coating


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14&

• I+ inspection turns up non-con+orming areas in t*e coating!

t*e piece may .e reJected%

• eJected articles may .e repaired

in t&o &ays

– -n plant pro*!ction repair – Da&age onsite repair

In (lant (roduction epairs


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144

Area o+ repair is signi+icant

• AS'/ A1E – One inch or less in narrowest dimension. – Total Area can be no more than ½ of 1 % percent of the

accessible area to be coated or 3 in.! per short ton per piece"whichever is less.

• AS'/ A1?E – The bare spots shall have an area totalin# not more than 1 %

of the surface area to be coated e$cludin# threaded areas of

the piece.

• AS'/ A@6@ – Total area in any 1 ft. len#th shall not e$ceed 1%

enovation '*ic:ness


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145

• '*ic:ness o+ enovation $%ecoating t%ic)ness of t%e re(aire* aream"st matc% t%e coating t%ic)ness oft%e s"rro"n*ing area@

• %"ception enovation *one Eit%inc Paints Eill ?e 50 3 %ig%er t%an

re!"ire* ?' $a?le 1+ ?"t not greatert%an 4@0 mils

AS'/ A@6@ 'ouc*-up epair


146/154



146

• I+ t*e coating +ails to meet t*ere>uirement +or +inis* and ad*erence!t*e .ar may .e stripped! regalvanized!and resu.mitted%

• Damage done to t*e coating due to+a.rication or *andling s*all .e repaired&it* a zinc-ric* +ormulation per AS'/A@8

• S*eared ends s*all .e coated &it* azinc-ric* +ormulation per AS'/ A@8%

AS'/ A@8Repair of Da&age* an* 0ncoate* Areas of

+otDip Galvanize* Coatings


147/154



14:

• 'ypes o+ /aterial Accepta.le +or epair

• S*all (rovide 9arrier (rotection and

(re+era.ly Anodic to Steel

• "ne Application o+ t*e /aterial N mils

– ollow &an!fact!rers *irections

• (ossi.le in S*op or ield

Accepta.le epair /et*ods


148/154



148

• inc-9ased Solders

• inc-ic* (aints

• inc Spray 4/etallizing5

inc-9ased Solders


149/154



14

• inc-Cadmium! inc-Copper-'in!inc-'in-0ead

•Sur+ace (reparation

• Application

• (er+ormance

inc (aints


150/154



150

• /ust contain .et&een 6?= and6


151/154



151

• '*is coating is t*e most similar tot*e galvanized coating inappearance and composition 4.utnot microstructure5%

• Cost is *ig*er%

• /ore di++icult to apply! re>uires atrained &or:er%

In Summary


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152

• Galvanized steel is steel &it* acorrosion protection coating+ormed .y t*e reaction .et&eensteel and molten zinc%

• '*e re>uirements +or galvanizingare outlined .y AS'/ A1E +orstructural steel products! AS'/

A1?E +or *ard&are! and AS'/ A@6@+or steel rein+orcement%

e+erences


153/154



15&

• ASTM Specifications• www3galvanizeit3org

3uestions and comments

http://www.galvanizeit.org/http://www.galvanizeit.org/


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inspectors course (presentation)-04-2012.ppt

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