Mercedes-BenzDBL9440

CompanyStandardDatepublished:2012-10

Supersedes:DBL9440:2010-05

Totalno.ofpages(incl.Annex):12

Personincharge:Dr.HessePWT/VWO

Dateoftranslation:2013-02Phone:+49-(0)71117-23506

FastenerswithMetricThread

SurfaceProtectionandSupplementary

TechnicalDeliveryConditions

Foreword

ThisDBLspecifies,inparticular,thecorrosionprotectionrequirementsforfastenerswithmetric(internalandexternal)thread.SurfaceprotectiontypesotherthanthosespecifiedinthisDBLwillonlybepermittedinexceptionalcasesforwell-foundedreasons.

Changes

Incomparisonwithedition2010-05,thefollowingchangeshavebeenmade:

?FormerAnnexAregardingPV.89deleted:transitionalsolutionforPV.89isnolongerrelevant

?FormerAnnexBrenamedAnnexA,andformerAnnexCrenamedAnnexB

?ReferencetoVDA235-204"HochfesteVerbindungselementefürdieAutomobilindustrie(High-StrengthFastenersfortheAutomotiveIndustry)"integrated

?andreferencetoMBN10436"PrüfungvonbeschichtetenInnengewinden(Testingofcoatedinternalthreads)"integrated

?Additionsandreferencestoqualitytopicsadded:

Particularlycarefulhandlingofpartsduringthecoatingprocess

Specificationof10partstobetestedinparallel

Specificationanddocumentationofthepart-relatedcoatingmaterialquantity

Recommendationoftestsbeyondthetargetspecifications

NOTE:Thistranslationisforinformationpurposesonly.

TheGermanversionshallprevailaboveallothers.

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Contents

1Scope 3

2Normativereferences 4

3Termsanddefinitions 5

4Generalrequirements 5

5Abbreviatedmaterialdesignationfordocumentation 6

6Processdescriptionandtechnicalrequirements 6

6.1Coatings 6

6.2Coefficientsoffriction/connectionbehaviorandfinishtreatment 7

6.3Requirementsforspecificproductgroups 8

7Tests 8

7.1Dimensionalstabilitytest 9

7.2Corrosionresistancetest 9

7.3Adhesiontest 9

8Samples 10

9Deliveries 10

AnnexA(normative)ProductsforproductversionaccordingtoDBL9440.89freefromCr(VI) 11

AnnexB(normative)Technologicaldataandtests 12

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1Scope

ThisDBLspecifies,inparticular,thecorrosionprotectionrequirementsforfastenerswithmetric(internalandexternal)thread.OthersurfaceprotectiontypesthanthosespecifiedinthisDBLwillonlybepermit-tedinexceptionalcasesforwell-foundedreasons.

Table1Cr(VI)-freeproductversions,overview

Product

version

Application

Appearanceof

coating

9440.20

Onlyinexceptionalcases,onlyforpartsforsubsequentpaintingoncommercialvehicles

Graytoblack

9440.40

StandarddesignofthisDBL

Zincflakecoatingwithlubricationintegratedintosealing

Silver

9440.43

Onlyinexceptionalcases

Zincflakecoatingwithoutsealingwithsubsequentlubricationbymeansoftouch-resistantlubricantforspecialconnectionrequirements,e.g.screw-connectionagainstpaintedfinishes.

Silver,dyed

bluishbysub-

sequentlubri-

cation

9440.47

Onlyinexceptionalcases

Electroplatedzinc-nickelcoats,transparentpassivated,sealed(ifrequired)forexceptionalanticorrosionrequirementsande.g.fornutswithsmalldimensions.Settingofthecoefficientoffrictionbysubsequentlubrication.

Blockingnote:Theuseofthisfinishhasnotyetbeenadequatelyverifiedforallapplicationconditions.Itshallthereforeonlybeusedfollowingapprovalbytheresponsiblefastenerrepresentative.

Silver,dyed

bluishbysub-

sequentlubri-

cation

9440.49

Onlyinexceptionalcases

Electroplatedzinc-nickelcoatswithadditionaltopcoatandsubsequentlubrica-tionforhighestexceptionalanticorrosionrequirements.

Blockingnote:Theuseofthisfinishhasnotyetbeenadequatelyverifiedforallapplicationconditions.Itshallthereforeonlybeusedfollowingapprovalbytheresponsiblefastenerrepresentative.

Silver,dyed

bluishbysub-

sequentlubri-

cation

9440.50

Forstylingandspecialrequirements

Black

9440.89

Onlyforfasteners≥M14foruseinvehicleswithagrossvehiclemassabove3,5t

Zincflakecoatingwithoutsealingwithsubsequentlubricationbymeansoftouch-resistantlubricant

Silver,dyed

greenishby

subsequent

lubrication

Withregardtoitsrequirements,productversion.89correspondstoproductversion.43withthediffer-enceofthedifferentcoloring,butinparticularthatonlycertaincoating/finishtreatmentmaterialsshallbeusedonboltsandscrewsaccordingtoproductversionDBL9440.89,whichareapprovedinAnnexAtothisDBL.

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ThisSupplySpecificationdoesnotapplytopartsofpropertyclass120or12.9/12!DBL9599appliestosuchparts.

ThisSupplySpecificationdoesnotapplytofastenerswithmicro-encapsulatedadhesive!DBL9460appliestosuchparts.

Otherwise,thisSupplySpecificationappliestoallmetricbolts,screwsandnutswithpropertyclasses≤10.9/10aswellastheirwashers,andtopipeconnectors,springclipsandsimilarpartsunlessotherwisespecifiedinproductstandards.

Surfacesforpartswhichareattachedtobodyshellsbymeansofwelding,screw-connectionorbondingandwhichtogetherwiththebodyrunthroughthepretreatmentandpaintingprocess,arenotcoveredbythisDBL.

Application-relatednote:

Thenewproductversionshavenotbeenverifiedforallapplicationconditionswithregardtotheiranticor-rosioncapabilityinareliableprocessandtheirtechnicalfasteningproperties.

Thisapplies,inparticular,tothecorrosionbehaviorofPVs.43/.89andthefasteningbehaviorofPVs.47and.49.

BeforePVs.47and.49areapplied,examinationswithregardtothefasteningtechnology,inparticular,andapprovalsbytheresponsiblefastenerrepresentativesarerequired.

2Normativereferences

Thefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument.Fordatedreferences,onlytheeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument(includinganyamendments)applies.

MBNVDA235-101

LubricationofThreadedFasteners1997-07

VDA235-2032005-08

Verschraubungsverhalten/Reibungszahlen–Praxis-undmontagegerechtePrüfung(ConnectionBehavior/FrictionCoefficients–PracticeandAssembly-OrientedTesting)

VDA235-204

HochfesteVerbindungselementefürdieAutomobilindustrie(High-StrengthFas-tenersfortheAutomotiveIndustry)

DBL8440

SupplySpecification;PartsManufacturedFromFerrousMaterialswithInorganicCoating(ZincFlakeCoatings)

DBL8451

SupplySpecification-ElectrodepositedZincorZincAlloyCoatingsforCompo-nentsManufacturedfromFerrousMaterials

DBL8585

SupplySpecification–GeneralRequirements-EnvironmentalProtection,Haz-ardousSubstances,DangerousGoods-NegativeSubstanceListfortheSelec-tionofMaterials

DBL9400

SupplySpecification;ThreadedPartsManufacturedfromFerrousmaterialswithOil-BakedorPhosphatedSurface

DINEN15205

DeterminationofHexavalentChromiuminCorrosionProtectionLayers-Quali-tativeAnalysis

DINENISO898-1

MechanicalPropertiesofFastenersMadeofCarbonSteelandAlloySteel

DINENISO6270-2

PaintsandVarnishes-DeterminationofResistancetoHumidity-Part2:Pro-cedureforExposingTestSpecimensinCondensation-WaterAtmospheres

DINENISO9227

CorrosionTestsinArtificialAtmospheres-SaltSprayTests

DINENISO10683

Fasteners-Non-ElectrolyticallyAppliedZincFlakeCoatings

DIN34804

Fasteners-ChangeofAppearanceofBlackSurfaces

MBN10248

ThreadedConnections-JoiningUsingThread-RollingScrews-DesignStand-ardforLightMetalCastingAlloys

MBN10436

PrüfungvonbeschichtetenInnengewinden(TestingofCoatedInternalThreads)

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3Termsanddefinitions

PV:ProductversionaccordingtothisDBL,e.g.DBL9440.40

Topcoats:

AtopcoatasdefinedbythisDBLisanorganicorinorganicprotectivelayerforzincflake,zincorzincalloycoatingswithlayerthickness>2μm.Thetopcoatmayalsocontainzincand/or

aluminumandincludepigmentsforcoloration(silverorblack).Topcoatsmaycontainsuitableadditivesfortheadjustmentofdefinedcoefficientsoffriction.

Passivation:

PassivationisthecreationofconversioncoatingsonnewlydepositedzincorzincalloylayersbytreatmentwithsuitableCr(VI)-freesolutions.

Separatetouch-resistantlubricant:

Alubricantwhichisappliedinadditionhasthefunctionofadjustingthetotalcoefficientoffric-tionsothatitlieswithintherangespecifiedinSection6.2,and-inlinewithMBNVDA235-101:1997-07-itshallnotimpairthecomponentfinishvisuallyorchemically,anditshallbedrytotouch,adherewellandshallnotleadtoanymalfunctionsinconveyingandprocessingsystems.Forfurtherrequirementswithregardtoappliedlubricants,refertoMBNVDA235-101:1997-07,Section2.2.

Sealing:

SealingasdefinedbythisDBListhecreationofanorganicorinorganicprotectivecoatingwithalayerthicknessofapprox.0,5-2μmonzincflake,zincorzincalloycoatings.Thesealingonzincorzincalloysurfacesisnormallyappliedonpassivatedsurfaces,wherebythesealing

penetratesintothepassivationlayerformingacompositecoating.Dependingonthesealingagent,thesealingshallbeexecutedwetonwetorfollowingintermediatedrying.Thesealingagentmaybeprovidedwithpigmentsforcoloration(black).Topcoatsorsubsequentpaintap-plicationswithgreaterlayerthicknessesshallnotbeusedassealings.

Sealingsmayincorporatesuitableadditivesfortheadjustmentoftherequireddefinedcoeffi-cientsoffriction.Thecombinationofsealingswithintegratedlubricantsandsubsequentlubri-cationshouldbeavoided,ifpossible.

Zincflakecoating:

Essentiallyinorganic,thincoatingwithcathodiccorrosionprotectioncapability,characterizedbythefactthatzincand,toalesserextent,alsoaluminumflakes,areappliedtothecompo-nentfromadispersion.Thecoatingconstituentswillevaporateandpolymerizeduringthesub-sequentbakingprocess.Inordertoachieveoptimumcorrosionprotection,thecoatingshall

normallybeappliedandbakedatleasttwice.

4Generalrequirements

Forsafetyrequirements,homologation(inparticular,exhaustemissions)andquality,theexistingstatuto-ryrequirementsandlawsshallbecompliedwith.Inaddition,therelevantrequirementsoftheDaimler

Groupapply.

Allmaterials,procedures,processes,components,andsystemsshallconformtothecurrentregulatory(governmental)requirementsregardingregulatedsubstancesandrecyclability.DBL8585shallbeob-served.

Duetothedetectionproblemsassociatedwithchromium(VI)inCr(VI)-freezincflakecoatings,theappli-cationofchromecompoundsforsuchcoatingsisnotpermitted.

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DetectionofCr(VI)

ThesuppliershallsupplyevidenceofthefreedomfromCr(VI)basedonrecognizedanalyticalmethods.SuchevidenceshallnormallybeprovidedinaccordancewithDINEN15205(formerlyDIN50993-1).PossiblecontaminationisacceptableinaccordancewiththeexceptioncurrentlyprovidedfromtheEU

ELVdirective(2000/53/EC)uptoacontentof0,1%byweightrelative

tothecorrosionprotectioncoating

(="homogeneousrange");otherwise,thedeterminationlimitforCr(VI)

hasbeenspecifiedat0,1μg/cm2

inaccordancewithDINEN15205basedontheinterlaboratorytestsperformed.

ThecorrosionresistancevaluesspecifiedinthisDBLshallbeattainedondeliverytotherelevantMer-cedes-Benzplants.

Dependingonthecoatingsystemandthegeometryanddimensionsofthefasteners,thecorrosionre-

sistancemaysignificantlydeteriorateasaresultofhandling,transportationandautomaticsortingpro-

cessesandfeedingequipment.Thisappliestoallsurfaceversions,butinparticulartozincflakecoatings.Thisrequirementshallbegivenspecialattentionduringaudits.

Forexplanationsandconcretenotesrelatingtopertinentimprovementmeasuresontheprocessside,refertotheguidelinesoftheDeutscherSchraubenverband(GermanFastenersAssociation)

"BerücksichtigungderSchütt-undTransportprozessebeiderUmstellungaufCr(VI)freieOberfl?chen“,editionApril2006.(

http://www.schraubenverband.de/DSV-Richtlinien.19.0.html

)

Inordertoensureaslittledamagetothecoatingaspossibleresultingfromfillingandtransportprocess-es,careshallbetakentoensurethatcoatingcompaniesandscrewsuppliershandlethepartsascareful-lyaspossible(e.g.byrestrictingthedropheightsto0,30-0,50m;useofslip-resistantmaterialsduring

fillingandslippingprocess).

5Abbreviatedmaterialdesignationfordocumentation

Thedesignationisallocatedinaccordancewiththerelevantproductstandardsinsteadoftheprevioussurfaceprotectionindications,e.g.:

ScrewwithexternalhexalobulardrivingfeatureandflangeMBN10142-M8x60-8.8DBL9440.40orfordrawingsintheblockforsurfaceprotectione.g.:DBL9440.40

6Processdescriptionandtechnicalrequirements

Thetechnicalconditionsofdeliveryspecifiedintheproductstandardsapply.Forfurtherinformation,refertoVDAmaterialsheet235-204aswellasDINENISO898-1.

6.1Coatings

Thepartsshallhavesmoothandcleansurfacesontheinsideandoutside,andtheyshallbefreeofcor-rosionproducts.

Tominimizemechanicaldamagetothethreadduringthecoatingofheavyscrewsandbolts,thethreadofscrewsandbolts≥M14isnormallysmoothedorre-rolledaftercoating.Inordertoreduceanyriskof

damage,rackcoatingorothersuitablegentlemethodsarealternativelypossibleforpretreatmentandcoating.

6.1.1Forthin-filmphosphating,alsorefertoDBL9400.40

6.1.2Forzincflakecoatings,alsorefertoDBL8440

WhenapplyingzincflakecoatingsaccordingtothisDBL,DBL8440,inparticularsection"Materialswithstrengths≥1000N/mm2“,shallbeobserved.

Thesupplyingfastenersuppliersareexpected,incooperationwithcoatingcompanies,tospecifythere-quiredminimumcoatingsystemmass(e.g.>30g/m2)specifictoeachcomponent.Compliancewiththisspecificationshallbecheckedregularly.

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Thecoatingprovidershallmonitorandcontrolthecoatingprocesswithzincflakecoatingsaswellasthedryingandbakingprocessofsuchlayers,inasfaraspossible,bycontinuousmeasurementofthepro-cessparameters.Thisincludes,besidesmanyotherparameters,e.g.temperaturemeasurementsatthedifferentprocesslocations,measurementofthehumidityduringthedryingprocessesofwaterbornezincflakecoatings,aswellasmonitoringtheviscosityofthecoatingliquidsbymeansofappropriate

measures.

Thesupplierofthesourcematerialofthecoatings(manufacturerofthetreatmentchemicals/coatingma-terials)isexpectedtointroduceasystemwhich,bymeansofregularauditsoftheusersofthecoatingmaterials(coatingcompanies),ensurestheabilityofthecoatingcompaniestoproduceahigh-gradeanduniformcoatingqualityinlinewiththerequirementsoftherelevantspecifiedDBL-PV.Thisshallbeat-testedbythesupplierofthesourcematerialofthecoatings.

Inaddition,thecoatingmaterialmanufacturershallenablethecoatingcompanytoassessthestabilityofitssubstancesinpracticaluse.

Asimilarprocedureisexpectedofthecoatingcompany.Auditsonthepremisesofthemanufacturerofthetreatmentchemicals/coatingmaterialsshallverifytheuniformityoftheproductsused,improvecom-municationbetweenbothsidesandassistindevelopingaproblemsolvingmanagementsystem.

Inpartswithcavitiesorrecesses(e.g.banjobolts,nuts)orsectionsofparts(e.g.drivingrecessofscrewsorbolts),accumulationsofcoatingmaterialdetrimentaltotheoperationofthepartarenotpermitted.

Anunevencoatingthicknesswiththeconsequentlessthanperfectanticorrosionpropertiesmayrestricttheapplicationofzincflakecoatingsforthreadedparts,e.g.inparticularsmallnuts.TheapplicationofelectroplatedcoatingsinaccordancewithPV9440.47ofthisDBLshouldbepreferredinthiscase.

Ifasubsequentadditionallubricationusingaseparatetouch-resistantlubricantisintendedonzincflakecoatingsandifsealingsystemsonzincflakecoatingsareused,nointegratedlubricantsshallbeusedinthese.

6.1.3Forelectrodepositedcoatings,alsorefertoDBL8451

WhenapplyingelectrodepositedcoatingsaccordingtothisDBL,sections"Materialsinstrengthrange1000N/mm2upto1150N/mm2"and"Materialswithstrengths≥1150N/mm2"ofDBL8451,inparticular,shallbeobserved.

Theconsequenceisthatforscrewsofpropertyclass10.9thematerialstrengthshallberestrictedto

1150N/mm2max.,andformaterialstrengths≥1000N/mm2appropriateheattreatmentsforhydrogeneffu-sionshallbeperformed.

6.1.4Zinc-nickelcoatingswithadditionaltopcoat(duplexlayers)inaccordancewithDBL

9440.49

Forthesecoatingsystems,thetypeoftheadditionalcoatingandsubsequentlubricationonthezinc-

nickelbaselayersisoptional,providedthatsystemsareinplacethatsignificantlyincreasecorrosionpro-tectionevenundermechanicalloadingofthefastenerscomparedtoconventionalpassivationandseal-ingsappliedinelectroplatingplants.

Note:TheinputrequiredforthemanufactureoftheduplexcorrosionprotectionsystemsspecifiedforthisPV,whentestedinaccordancewithDINENISO9227NSS,resultsinmuchlongerpotentialperiodsuntilbasematerialcorrosionthanthetestperiodsof1008hrequiredinthisDBL.

Itisplannedinthefuturealsotodefinemechanicalloadswhichhavetobetoleratedbythesesystemswithoutnegativeeffectsonthecorrosionresistance.

6.2Coefficientsoffriction/connectionbehaviorandfinishtreatment

InaccordancewithMBNVDA235-101:1997-07,atotalcoefficientoffrictionof

μtot.=0,08to0,14shallbesetforallthreadedparts.

Forsimilarpartswithspecialconfigurationswhereacoefficientoffrictioncannotbedetermined,thefinishtreatmentshallalsobecarriedoutinsuchawaythatcorrespondingpartswithoutthespecialconfigura-tionwouldachievetherelevantvaluerange(e.g.forself-lockingscrews).

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TreatmentinaccordancewithMBNVDA235-101:1997-07fortheproductversionsidentified"withinte-gratedlubricant"accordingtoAnnexBshallbeperformedbymeansofalubricantintegratedintothe

seal.Thebaselayershallbeexecutedfreefromlubricants.

ExceptionDBL9440.40:

Ifinthecaseofparts≤M8withdrivingrecess,thesealwithintegratedlubricantcausesdimensionalproblemsinthedrivingrecess,theuseofalubricantisalsopermittedinplaceoftheseal.

Formetricthreadrollingscrews(e.g.inaccordancewithMBN10248)orall-metalprevailingtorquenuts,anadditionallubricationtreatmentmayberequiredtoensurethatthepermittedrollingorclampingtor-quesaremaintained.Thismayalsoapplytodrawingpartsinspecificassemblysituations.

WhenacoatstructureorfinishtreatmentinaccordancewithMBNVDA235-101:1997-07isusedforthefirsttime,andduringinitialsampling,thesuppliershallprovideevidencethattheproductselectedbyhimforsettingthecoefficientoffrictionrangehasthedesiredconnectionbehavior(validation).ThisevidenceshallbebasedonsystematicexaminationsinaccordancewithVDATestSheet235-2032005-08,andtheresultsoftheexaminationsshallbesubmitted.

Thegeometry-relevantdataforthegeometryspecifiedforsampling(e.g.threadsize,underheadgeome-try)shallbesubmittedwiththeinitialsamples.

Example:AsampleofascrewM14*1,5*70inaccordancewithMBN10143issubmitted.ThesupplierisexpectedtoenclosethevalidationresultsofascrewwiththreaddimensionM14*1,5inanyoptional

lengthwithcomparable/similarunderheadgeometry.ThismayalsobeascrewinaccordancewithMBN10105,forexample.

Recordsshallberetainedandpresentedduringasupplieraudit.

Anadditionallubricanttreatmentonsealings/topcoatswithintegratedlubricantshallbedocumented,resampledandapproved.

Inthesecasesandforproductversionsmarkedwithseparatelubricant,alubricantshallbeusedwhichcreatesatouch-resistantfilmandcomplieswiththerangeofpropertiesspecifiedinVDA235-101Section2.2.WiththeexceptionofPV.20andPV.50,thelubricantshallbedyedbluish,andinthecaseofPV.89greenish,andshallnotpossessanyUVadditives.

6.3Requirementsforspecificproductgroups

6.3.1Nutswithplasticprevailingtorqueelement

Fornutswithplasticprevailingtorqueelement,generallyonlymethodswithbakingtemperaturesofap-prox.200°Candplasticssuitablefortheapplicationshallbeused;iftheplasticprevailingtorqueelementisinsertedaftersurfacecoating,therequiredcorrosionresistancevaluesshallbeassuredevenfollowingthecrimping-inprocess.Inthiscaseandiftemperature-sensitiveplasticprevailingtorqueelementsareused,theexaminationoftheuseofproductversions.47isrecommendedasexperienceshowsthat

thesecoatstructuresarenotimpairedasmuchbythecrimpingprocess.

6.3.2Pipeconnectors

Zincflakecoatingsonpipeconnectorsshallbeappliedonlybycompaniesforwhichthequalitymanage-mentunitofthereceivingplanthasspecificallygrantedanapprovalofprocurementsource.

Forpipeconnectorswithzincflakecoatingsconveyingairnolooseparticlesoraccumulationsofthecoat-ingmaterialarepermittedwhichcouldimpairthefunctionalavailabilityoffinevalvesorboreholeswithinthesystemwherethepipeconnectorsareused.

Forpipeconnectorsconveyingliquidwithelectrodepositedcoatingstherearenointernalcorrosionpro-tectionrequirements.Themanufacturershallensure,however,thattheinternalareasareprovidedwithanadequatetransportandstorageprotectionsothatcorrosion-freedeliverytoMercedes-Benzfactoriesisensured.

7Tests

Foradescriptionofacceptablecoatstructures,testsandrequirements,seeAnnexB.

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7.1Dimensionalstabilitytest

Inthecaseoftestswiththreadringgage,thedimensionalstabilityofthetestspecimensistherefore

deemedsatisfactoryifthethreadringgagecanstillbescrew-tightened,evenifagainstresistance(tight-eningtorque),butwithoutotheraids/tools.

Inrefereecases,DINENISO10683specifieslimittighteningtorquesforthetestingofthetruenesstogage.Thegagemeasurementappliestotheas-suppliedcondition.

Forpartswithinternalthread,thetestshallbeperformedinaccordancewithMBN10436.

Forzincflakecoatings,inparticularthosewithadditionalorganictopcoats,notethatanymaterialaccu-mulationsonthebearingsurfaces(e.g.underneaththebolthead)ofthreadedpartsmayleadtoanunac-ceptablesettingbehavior.Suchaccumulationscanthereforeonlybetoleratedifnoexcessivenegative

influenceonthesettingbehaviorisobserved.Noreliablelimitvaluesexistyet,butexperiencesofar

showsthatamaximumvalueof25μmstillappearstobeacceptableformaterialaccumulationsunderthebearingsurfacesofthreadedparts.

Unevenaccumulationsofcoatingmaterialsonthesurfacesofthethreadedpartsdisturbingthetighteningandfunctionalpropertiesandtheconveyingandfeedingofthethreadedpartstothefasteninglocationsarenotpermitted.

7.2Corrosionresistancetest

ThecorrosionresistancetestisdeemedtohavebeenpassedwheneachrespectiverequirementinAn-nexBofthisDBLiscompliedwith.

Thescrewsuppliershould,however,carryoutcorrosiontestsbeyondthetimeperiodsrequiredinthisDBLinordertogenerateknow-howregardinghowgreatthegapisbetweentheactualcoatingqualityandtherequiredlimitandregardingthescatterofthecoatingquality.

Foreachvariant,atleast10screwsforeachindividualtesttypeshallbetested.Therequirementforthetestperiodwithoutbasematerialcorrosionalsoappliesifinapartofthescrews(i.e.drivingrecesses)testsubstanceaccumulates.

Therequiredcorrosionprotectionpropertiesshallbeachievedforcaseswhereseparatelubricantsareusedbothintheoriginalconditionandindegreasedcondition(e.g.usingpetroleumether).

Theanti-corrosioncoatingsshallnotdemonstrateanyblistersorpeelingduringthespecifiedcorrosiontestsafterthespecifiedtestperiod.

CorrosiontestingasperDINENISO6270-2iswaived.Notwithstandingthisstipulation,thesuppliershallprovideevidenceatthetimeofinitialuseofacoatstructurethattheselectedproduct/coatstructuredoesnotshowanyweaknesseswithregardtothiscorrosionstress(systemtest/validation).Therequirementisthatthecoatingsystemsusedinconstantcondensationwateratmospherepreventanybasematerialcorrosionforatleast720h.

7.3Adhesiontest

7.3.1Adhesiontest:zincflakecoatingsinaccordancewithDBL9440.40,DBL9440.43andDBL

9440.89

Totestthelayeradhesiononthebasematerial,anadhesivetextiletapewithanadhesiveforceof7±1Nper25mmwidthshallbepressedonfirmlybyhandandthenabruptlytornoffatgreatspeedverticallytothes