S-BT Threaded Fastener Specification

Table Of Contents
page90 Specifications
5.10.3 CarbonsteelS-BTstuds
General comments
The coating of the carbon steel S-BT fasteners consists of an electroplated Zn- alloy
forcathodicprotectionandatopcoatforchemicalresistance(Duplex-coating).
Thethicknessofthecoatingis35μm.Theuseofthiscoatingislimitedtothe
corrosioncategoryC1,C2andC3accordingthestandardENISO9223.Forhigher
corrosioncategoriesstainlesssteelfastenersshouldbeused.
Thankstoextensiveresearchinclosecooperationwithrenowneduniversitiesand
laboratories,designerscantrustandrelyonthemultilayercoatingforS-BT.
Indoor applications
Dry indoor environments
(heatedorair-conditionedareas)withoutcondensation,
e.g.ofcebuildings,schools
Indoor environments with temporary condensation
(unheatedareaswithoutpollutants),e.g.storagesheds
Outdoor applications
Outdoor, rural or urban environment with low pollution
Largedistance(>10 km)fromthesea
Outdoor, rural or urban environment with moderate concentration
of pollutantsand / orsaltfromseawater
Distancefromthesea1–10 km
EnvironmentalconditionsforusageofcoatedcarbonsteelS-BTstuds
Note: ETA-20 / 0530allowstheuseofcarbonsteelthreadedstudswithduplex
coatingonlyindryindoorenvironment(C1acc.toENISO9223)
Test concept
Laboratoryandeldtestsareperformedtoassesstheexpectedlifetimeand
technicalsafetyaspectsforfasteners.TheduplexcoatingontheS-BTwastested
inneutralsaltsprayaccordingtoDINENISO9227,whichisthemostcommonly
usedacceleratedcorrosiontestforcorrosionassessment.Thistestissuitablefor
qualityassessmentbutdoesnotreectrealenvironmentalconditions.
Incontrast,cycliccorrosiontestslikeISO16701reproduceandaccelerate
corrosionmechanismsthatoccurunderrealenvironmentalconditions.Thistest
iswelladaptedforlifetimeassessmentundermoderateatmosphericconditions.
Thefastenersaresubjectedthroughcycledclimateconditionssuchastempera-
turevariations,humidityanddryperiodsaswellascorrosionattackthroughsalt.
Resultsoflaboratorytestsareveriedbymid-andlongtermeldtestsinnatural
climatic conditions.
Duringthesettingprocess,thefastenerissubjectedtostrongimpacts.Toensure
thatthecorrosionresistanceoftheS-BTremainsintact,Hiltiperformsallcorrosion
testsonS-BTinmountedconditionandthefastenersareinstalledinsteelplates
withthenecessarytools.
Top coat for chemical resistance
Zn-alloy electroplating for cathodic protection
Hardened carbon steel
Duplex-coatingoncarbonsteelS-BT
fasteners
PreparedS-BTfastenings
RemovedS-BTfastenersafter12weeks
EN ISO 16701 cyclic corrosion test.
Novisiblecorrosion.