Designation:D4145−10StandardTestMethodforCoatingFlexibilityofPrepaintedSheet1ThisstandardisissuedunderthefixeddesignationD4145;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethoddescribesaprocedurefordeterminingtheflexibilityandadhesionoforganiccoatings(paints)onmetallicsubstratesthataredeformedbybendingwhenthesheetisfabricatedintobuildingpanelsorotherproducts.1.2Themetalsubstratemustbecapableofpassingthistestwithoutfracturingandwithnoexcessivegraindevelopment.1.3Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.Terminology2.1DefinitionsofTermsSpecifictoThisStandard:2.1.1T-bend,n—adescriptionoftheseverityofabendintermsofthegaugeorthickness(t)ofthesheettowhichthecoatinghasbeenapplied;asusedinthistestmethod,theT-bendratingistheminimumnumberofthicknessesofmetalaroundwhichthecoatedsheetisbent(Fig.1),orifbentaroundadie,thenumberofthicknessesofmetalequivalenttothediameterofthedietoachievenofractureorremovalofthecoating.3.SummaryofTestMethod3.1Prepaintedpanelsarebent180°aroundprogressivelymorethicknessesofmetalorlargerdiameterdies,theendpointbeingwhenfailuresnolongeroccur.Thepanelsmaybeexaminedwithorwithoutlowmagnification(5to10×)aftereachbendinordertodetermineifthecoatingfractured(cracked).Iflossofadhesionorpickoffistobedetermined,thisexaminationshalloccurafterperformingatapepull-offtest.4.SignificanceandUse4.1Organiccoatingsonprecoatedsheetaresubjectedtostresseswhenfabri...
