MPIF35-2007(美国粉末冶金结构零件材料标准)

Nopartofthispublicationmayberepro-duced,storedinaretrievalsystem,ortransmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recordingorotherwise,withoutthepriorpermissionofthepublisher.©Copyright2007ISBNNo.0-9762057-8-5PublishedbyMetalPowderIndustriesFederation105CollegeRoadEastPrinceton,NewJersey08540-6692U.S.A.Tel:[phone]Fax:[phone]E-mail:[e-mail]:(PM)materialsthathavebeendevelopedbythePMpartsmanufacturingindustry.ThissectionofStandard35dealswithcon-ventionalPMmaterialsforstructuralparts.ItdoesnotapplytomaterialsforPMself-lubricatingbearings,powderforged(P/F)ormetalinjectionmolded(MIM)productswhicharecoveredinseparateeditionsofMPIFStandard35.Thesamematerialsmayappearinmorethanonesectionofthestandarddependingupontheircommonuse,e.g.,somestructuralmaterialsmayalsobeusedinbearingappli-cationsandviceversa.EachsectionofthisstandardisdividedintosubsectionsbasedonthevarioustypesofPMmaterialsincom-moncommercialusewithinthatsection.Notesatthebeginningofeachsubsectiondiscussthecharacteristicsofthatmaterial.TheuseofanyMPIFStandardisentirelyvoluntary.MPIFStandardsareissuedandadoptedinthepublicinterest.Theyaredesignedtoeliminatemisunderstandingsbetweenthemanufacturerandthepurchaserandtoassistthepurchaserinselectingandobtainingthepropermaterialforaparticularproduct.ExistenceofMPIFStandardsdoesnotinanyrespectprecludeanymemberornon-memberofMPIFfrommanufacturingorsellingproductsthatusematerialsortestingproceduresnotincludedinMPIFStandards.Othersuchmaterialsmaybecommerciallyavailable.BypublicationoftheseStandards,nopositionistakenwithrespecttothevalidityofanypatentrightsnordoesMPIFundertaketoensureanyoneutilizingtheStandardsagainstliabilityforinfringementofanyLettersPatentoracceptanysuchliability.NeitherMPIFnoranyofitsmembersassumesoracceptsanyliabilityresultingfromuseornon-useofanyMPIFStandard.Inaddi-tion,MPIFdoesnotacceptanyliabilityorresponsibilityforthecomplianceofanyproductwithanystandard,theachievementofanyminimumortypicalvaluesbyanysupplier,orfortheresultsofanytestingorotherprocedureundertakeninaccordancewithanyStandard.MPIFStandardsaresubjecttoperiodicreviewandmayberevised.Usersarecautionedtorefertothelatestedition.New,approvedmaterialsandpropertydatamaybepostedperiodicallyontheMPIFWebsite.Betweenpublishededitions,goto:minimumstrengthvalue,gradeselection,chemicalcomposition,prooftesting,typicalpropertyvaluesandprocesses,thatmayaffectthepartapplication.1MinimumValueConceptTheMetalPowderIndustriesFederationhasadoptedtheconceptofminimumstrengthvaluesforPMmaterialsforuseinastructuralapplication.ThesestrengthvaluesmaybeusedindesigningforaPMpartapplication.Itshouldbenotedthatthepowdermetallurgyprocessoffersequivalentminimumtensilestrengthvaluesoverawiderangeofmaterials.Itisseenasanadvantageoftheprocessthatequivalentstrengthscanbedevelopedbyvaryingchemicalcomposition,particleconfiguration,den-sityand/orprocessingtechniques.Asanaidtotheuserinselectingmaterials,inadditiontominimumstrengthvalues,typicalvaluesforotherprop-ertiesarelisted.ThismakesitpossiblefortheusertoselectandspecifytheexactPMmaterialandpropertiesmostsuitableforaspecificapplication.Thedataprovideddefinevaluesforlistedmaterialsanddisplaytypicalmechanicalpropertiesachievedundercommercialmanu-facturingprocedures.Physicalandmechanicalpropertyperformancecharacteristicsmaybechangedbytheuseofprocessingstepsbeyondthosedesignatedinthisstan-dard.Toselectamaterialoptimuminbothpropertiesandcost-effectiveness,itisessentialthatthepartapplicationbediscussedwiththePMpartsmanufacturer.MinimumValueForstructuralPMmaterialsintheas-sinteredconditiontheminimumvalueisexpressedintermsoftheyieldstrength(0.2%offsetmethod)inthousandpoundspersquareinch(103psi)ormegapascals(MPa).ForstructuralPMmaterialsintheheattreatedcondition(quenchedandtempered),theminimumvalueexpressedisultimatetensilestrengthinthousandpoundspersquareinch(103psi)ormegapascals(MPa).WhenPMmaterialsareheattreated,tensilepropertiesandhardnessincrease;nevertheless,thefailuremodeissuchthat0.2%offsetyieldpointsarenotalwaysattainable.Theyieldandultimatetensilestrengthsarethereforeapproximatelythesameforheattreatedmaterials.(SeeHeatTreatmentandSinterHardeningpage3).Forsoft-magneticmaterialsthemaximumvalueisexpressedintermsofthecoercivefieldinoerstedsx10.ThetensilepropertiesutilizedforestablishingthisStandardwereobtainedfromtensilespecimenspreparedspecificallyforevaluatingPMmaterials.Tensilepropertiesofspecimensmachinedfromcommercialpartsmayvaryfromthoseobtainedfromindividualspecimenspreparedspecificallyforevaluati