FROSIO考试99个问问答.docx
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FROSIO考试99个问问答.docx
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FROSIO考试99个问问答
The99questions
1.Whatconditionisessentialforgalvanic(bimetallic)corrosiontooccur?
Oxygen;electrolyte;(twometalshaving)differentpotentials
2.Howdowerecognizeturbulencecorrosion?
Incopperwecanfindsharplydefinedpitswhichcommonlyareundercutonthesidefacingthewater’sdirectionofflow
3.Whenweusethetermdegraphitationofcastiron,whatkindofcorrosiondowereferto?
Selectivecorrosion
4.Degraphitationisaspecialformofbimetalliccorrosionandeitherironorthesteelisconsumed
throughdissolution.Whichofthetwosubstanceswillgotodissolution?
Iron(willsacrificeitselfforgraphiteleavingthesurfaceasalayer.Thislayerhasno
mechanicalstrength,howevertheobjectlooksintact.Thegraphitemaybeeasilyremovedwith
e.g.aknife.
5.Mostofcoatingsfunctionbythebarrierprincipal.Againstwhatisthecoatingbarrier?
(against)liquid;waterandpartlyoxygen
6.Doseacoatingheavilypigmentedwithzincphosphateprovidecorrosionprotectionbythe
galvanicprinciple?
No,byinhibitorprinciple
7.Whyisasurfaceprofileimportanttoadhesionofacoatingsystem?
Itenlargertheareatocontact,providinganchorage
8.Howdowechecksurfacesforametalcleanlinessofsa3ensurethatallsolublesubstancesare
removedfromthesurface?
AccordingtoISO8502-6andISO8502-9.
Sampling(“Breslemethod”)andmeasuretheconductivity.
9.Willblastingsteelsurfacetoametalcleanlinesssa3ensurethatallsolublesubstancesare
removedfromthesurface?
No,itcanonlyremovepartly.
Freshwaterwashingwilldoit.
10.Whatmustbedonetothesteelsurfacebeforegrinding?
Steelpreparationfirst(removingweldslag/weldspatter,chippingofflamination),then
removingoil/greaseand/orwatersolublesubstancesbysolventcleaningand/orHPWwashing
11.Whyisasteelsurface,whichhasbeenburnishedthroughrotarywirebrushingnotavery
goodsurfacetoapplypaint?
Itistoomuchsmooth,thereisnogoodadhesionbetweenthecoatingandthesurface
12.Whatisthefunctionofamoistureseparatoronacompressor?
Toseparatewaterfromthecompressedair
13.Whatistheeffortofincreasingthedistancefromtheblastnozzletothesurface?
Itwilllosskineticenergy(shallowroughness/poorblasting)
14.Whichangle(theblastingnozzletosurface)shouldyouselectwhenblastingoffmostpartsof
thick,whichiswelladhesionepoxymasticsystem?
45to60degreeangle
15.Whatproblemconnectedtothepaintsystem’sservicelifecanyougetifyouuseaninhibitor
inconnectingwithwaterjetting?
Givelaterosmoticblisteringandaffecttheadhesionbetweenthepaintandthesubstrate.
16.Iswaterjettingsuitedforprimarysurfacepreparation?
Ifyouthinkso,pleasestatewhy?
If
youthinknot,pleasestatewhy?
No,itisonlysuitedforsecondarysurfacepreparation,becauseitdosenotcreategood
surfaceroughness
17.If,afterblasting,flashrustappearsrathermorequicklythanusual,whatcouldindicate?
Thereiswatersolublesubstanceonsurface;thereiscondensationonsurface;thehumidityis
high
18.WhatisthelowersliquidpressureaccordingtothejointSSPC/NACEstandardthatis
designatedwaterjetting
70Mpa(10000psi)
19.Whatislaitance?
Itistheoutercrustoffreshlycastconcrete.
20.Wherecanyoufindinformationsuchasthepotlifeofacoating?
Intheproductdatasheet.
21.Whenpaintsarestoredforlongperiodsoftime,whatcomponentsettlestothebottom?
Thepigmentwillsettletothebottom
22.Howcanyougetridofairthathasbeenmixedintoliquidpaintbeforeapplication?
Putisawhile,theairwillreleasetheairbyitselfintheinductiontime
23.Whateffectsdothetemperaturehasonthepotlifeofpaint?
Ifthetemperatureincrease,thepotlifewillreduce;ifthetemperaturereduce,thepotlifewill
increase.
24.Whenwouldyouuseamoisture/oiltrapbetweenanaircompressorandthepressurepotinan
airsprayunit?
Themoisture/oiltrapwouldbealwaysusedwhenyouanairsprayunit
25.Whydosepaint“wraparound”tothesidesandthebackofanobjectduringelectrostaticspray
application?
Thepaintisgivenanelectrostaticcharge(usu.negative),theobjectisearthed,thenegative
chargedpaintparticlesareattractedtoallpartsofobjectandthebuildupofpaintisespecially
goodonedges.
26.Whatdegreeofmetalcleanlinessisrequiredforthermalsprayingofametalliccoating,and
whatshouldthesurfaceprofilebe?
Sa3and50-80um
27.Whichmetalsaretheonesmostcommonlyusedinthermalsprayapplication?
Aluminumalloyandzincalloy
28.Whatisinductiontime?
Somepaintsneedtositforawhilepriortouseinorderforthetwocomponentstostart
reacting,thisperiodoftimeiscalledinductiontime
29.Whateffectwillhotweatherhaveonthepotlifeachemicalcuringcoating?
Hotweatherwillshortenthecuringtime
30.Whatisapotlife?
Whenthetwocomponentspaintismixed,itonlyhasashortperiodoftimebetweenthe
Mixingpointandthepointatwhichthepaintcured,cannotbeusedanymore,thisperiodof
Timeiscalledpotlife.
31.Whatisawaterbornecoating?
Inawaterbornecoatingtheorganicsolventsarealmostabsent,andthebinder,informof
smallspheroidsisdispersedinwater.
32.Whateffectwilllowtemperatureandhighhumidityhaveonthedrying/curingofwaterborne
coating?
Therewillbecondensationonthecoatingsurface,thecoatingmaynotdry/cure
33.“waterbornecoatingdosenotcontainanysolventatall”,Isthisacorrectstatement
Thisisnotcorrect.Waterbornecoatingcontainasmallamountofspecialsolvent—
plasticiser(usu.<6%)
34.WhateffectwillincreasingthesolidscontentofacoatinghaveontheVOClevelofacoating?
TheVOCwillbelowered
35.Whateffectwillthinninghaveonthefilmbuildingpropertiesofacoating?
Itwillleadsagging/runs;youwillincreasetheWFTinordertoachievethespecifiedDFT
36.WhatdoseSSPC-SP10designate?
Verythroughblastcleaning—nearwhitemetalblastcleaning
(ISOsa21/2)
37.Onaworksiteyoufindthatthewindisblowingsteadilyatapace15milesperhour.Willthis
affectairlesssprayapplicationofzincethylsilicate?
Yes,thevelocityistoohigh.Themaximumpermitis7.2km/hr
38.Whyshouldthesteeltemperatureduringblastingorpaintapplicationbeatleast3*cabovethe
dewpoint?
Avoidcondensationtoensuregoodadhesion
39.Howdowedetermineifablastedsteelsurfacetherequiredmetalcleanlinessornot?
YoucandeterminebyusingthestandardISO8501-1(withphotos)
40.WhatdoesPSa3designate?
Partial(localized)blastingtosa3toapreviouslycoatedsurface.
41.AndPSt2?
partial(localized)handorpowertoolcleaningtost2toapreviouslycoatedsurface.
42.Whatisthedifferencebetweenaspecificationandprocedure?
Aspecificationtellswhatwillbedone,aproceduretellshowwillbedone.
Aspecificationcomprisetheelementsnecessarytodescribetheresultaimedat.
Aproceduremustcoverallaspectsofthework–notonlysurfacepreparationandapplication.
43.“Reportingisdemandedtomakelifedifficultforcoatingadvisersandensurethattheydonot
gotobarsandloosewomen”isthisstatementcorrect?
Pleasejustifyyourviewpoint
regardlessofweatherornotyouagreewiththestatement?
No,Idonotagreewithit.Reportingisveryimportant,everythingshouldbewrittendown
clearlysothatwecanfindthereasonseasilyifsometroubleshappen.
44.Whyisitnecessarytoremovegreasefromasurfacepriortoblastcleaning?
Forblastcleaningwillnotfullyremovethegrease,instead,itwillspotthegreaseeverywhere.
45.Whenyouhaveremovedleadcontainingpaintfromsurfacethroughgrindingshouldyouthen
takeyourworkclotheshomeandwashthembyhands?
No,throwthemaway.
46.Whatistheflashpoint?
Flashpointisthelowesttemperatureatwhichaliquidliberatessufficientvaportoforma
mixturewiththeairnearitssurfacewhich,ifignited,willmakeasmallflash,butnotcatch
fire.
47.Howdowecheckthesurfaceprofileachievedonacleanedsurface?
ComparewithstandardISO8503
48.Howlongshallyoutwirlaslingpsychrometerinordertodeterminethewetanddry
temperature?
Donotstopuntilthetwothermometersstable.
49.Ifyouuseawornnozzleonanairlessspraygun,howwillthisaffectthethicknessofthewet
filmdepositedonthesurfaceascomparedtoanidenticalbutunusednozzle?
Highfilmthickness/maybesagging/orangepeel/
50.Whatshouldyoudoifyourreceiveashipmentofcoatingswhichhaveexceedtheirpotlife?
Returnthemback,reportaccordingly.
51.Whatdowemeanbytheoreticalcoverage?
Itisdefinesastheareaofsurfacethatcanbecoveredatuniformspecifieddryfilmthickness
byaspecifiedunitvolumeofacoatingintheory.
52.Whydowespecifyacertaindryfilmthicknessforacoatofpaint?
PLSlistentotheprofessor.
53.Whatcheckwouldyoubelikelytomaketofindthecauseoffisheyeinapaintfilm?
Oil/grease,silicone,dirt
54.Whatisthemaincausesofthebelowpaintfilmdefects?
Wrinkling:
a.Toothick
b.weathertoowarm
Orangepeel:
a.Painttooviscous
b.guntooclose
c.toofastsolventevaporation
d.toolowairpressure.
Pinhole:
a.Solvent/airpassagethroughthefilm
b.insufficientatomization
c.coarseatomization
d.settledpigment(s)
Dryspray:
a.Guntoofaraway
b.toohighatomization
c.incorrectspraytechnique
d.fall-outfromwind
e.toohighairtemperature
Sagg
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- FROSIO 考试 99 问答