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1MATERIALSELECTIONANDHEATTREATMENTOFMETALDURINGRECENTYEARSTHESELECTIONOFENGINEERINGMATERIALSHASASSUMEDGREATIMPORTANCEMOREOVER,THEPROCESSSHOULDBEONEOFMAYBEADECREASINGAVAILABILITYOFTHEMCONCERNSREGARDINGENVIRONMENTALPOLLUTION,RECYCLINGANDWORKERHEALTHANDSAFETYOFTENIMPOSENEWCONSTRAINTSTHEDESIREFORMIGHTREDUCTIONORENERGYSAVINGSFOREIGNCOMPELLATION,INCREASEDSERVICEABILITYREQUIREMENTS,ANDCUSTOMERLIABILITYACTIONS,OFTENTHERESULTOFIMPROPERMATERIALUSE,HASHADAMARKEDIMPACTINADDITION,THEINTERDEPENDENCEBETWEENMATERIALSANDTHEIRPROCESSINGHASBECOMEBETTERRECOGNIZEDTHEDEVELOPMENTOFNEWPROCESSESOFTENFORCESREEVALUATIONOFTHEMATERIALSBEINGPROCESSEDTHEREFORE,ITISIMPERATIVETHATDESIGNANDMANUFACTURINGENGINEERSEXERCISECONSIDERABLECAREINSELECTING,SPECIFYING,ANDUTILIZINGMATERIALSIFTHEYARETOACHIEVESATISFACTORYRESULTSATREASONABLECOSTANDSTILLASSUREQUALITYTHEFIRSTSTEPINTHEMANUFACTUREOFMYPRODUCTISDESIGN,WHICHUSUALLYTAKESPLACEINSEVERALDISTINCTSTAGESACONCEPTUAL；BFUNCTIONAL；CPRODUCTIONDESIGNDURINGTHECONCEPTUALDESIGNSTAGE,THEDESIGNERISCONCERNEDPRIMARILYWITHTHEFUNCTIONTHEPRODUCTISTOFULFILL,USUALLYSEVERALCONCEPTSAREVISUALJAILSANDCONSIDERED,ANDADECISIONISMADEEITHERTHATTHEIDEAISNOTPRACTICALORTHATTHEIDEAISSOUNDANDONEORMOREOFTHECONCEPTUALDESIGNSSHOULDBEDEVELOPEDFURTHERHERE,THEONLYCONCERNFORMATERIALSISTHATMATERIALSEXISTTHATCANPROVIDETHEDESIREDPROPERTIES,IFNOSUCHMATERIALSAREAVAILABLE,CONSIDERATIONISGIVENASTOWHETHERTHEMISAREASONABLEPROSPECTTHATNEWONESCOULDBEDEVELOPEDWITHINCOSTANDTIMELIMITATIONSATTHEFUNCTIONALORENGINEERINGDESIGNSTAGE,APRACTICAL,WORKABLEDEIGNISDEVELOPEDFAIRLYCOMPLETEDRAWINGSAREMADE,ANDMATERIALSARESELECTEDANDSPECIFIEDFORTHEVARIOUSCOMPONENTS0FTENAPROTOTYPEORWORKINGMODELISMADETHATCANBETESTEDTOPERMITEVALUATIONOFTHEPRODUCTASTOFUNCTION,RELATIVITY,APPEARANCE,SERVICEABILITY,ANDSOONALTHOUGHITISEXPECTEDTHATSUCHTESTINGMIGHTSHOWTHATSOMECHANGESMAYHAVETOBEMADEINMATERIALSBEFORETHEPRODUCTISADVANCEDTOTHEPRODUCTIONDESIGNSTAGE,THISSHOULDNOTBETAKENASANEXCUSEFORNOTDOINGATHOUGHJOBOFMATERIALSELECTIONSAPPEARANCE,COSTANDRELIABILITYFACTIONSHOULDBECONSIDEREDINDETAIL,TOGETHERWITHTHEFUNCTIONALFACTORSTHEREISMUCHMERITTOTHEPRACTICEOFONEVERYSUCCESSFULCOMPANYWHICHREQUIRESTHATALLPROTOTYPESBEBUILTWITHTHESAMEMATERIALSTHATWILLBEUSEDINPRODUCTIONAND,INSOFARASPOSSIBLE,WITH2THESAMEMANUFACTURINGTECHNIQUESITISOFLITTLEVALUETOHAVEAPERFECTLYFUNCTIONINGPROTOTYPETHATCANNOTBEMANUFACTUREDECONOMICALLYINTHEEXPECTEDSALESVOLUME,ORONETHATISSUBSTANTIALLYDIFFERENTFROMWHATTHEPRODUCTIONUNITSWILLBEINREGARDTOQUALITYANDRELIABILITYALSO,ITISMUCHBETTERFORDESIGNENGINEERSTODOACOMPLETEJOBOFMATERIALANALYSIS,SELECTION,ANDSPECIFICATIONATTHEDEVELOPMENTSTAGEOFDESIGNRATHERTHANTOLEAVEITTOTHEPRODUCTIONDESIGNSTAGE,WHERECHANGESMAYBEMADEBYOTHER,POSSIBLYLESSKNOWLEDGEABLEABOUTALLOFTHEFUNCTIONALASPECTSOFTHEPRODUCTATTHEPRODUCTIONDESIGNSTAGE,THEPRIMARYCORNERRELATIVETOMATERIALSSHOULDBETHATTHEYARESPECIFIEDFULLY,THATTHEYARECOMPATIBLEWITH,ANDCANBEPROCESSEDECONOMICALLYBY,EXISTINGEQUIPMENT,ANDTHATTHEYAREREADILYAVAILABLEINTHENEEDEDQUANTITIESASMANUFACTURINGPROGRESSES,ITISINEVITABLETHATSITUATIONSWILLARISETHATMAYREQUIREMODIFICATIONSOFTHEMATERIALSBEINGUSEDEXPERIENCEMAYREVEALTHATSUBSTITUTIONOFCHEAPERMATERIALSCANBEMADEINMOSTCASES,HOWEVER,CHANGESAREMUCHMORECOSTLYTOMAKEAFTERMANUFACTURINGISINPROGRESSTHANBEFOREITSTARTSGOODSELECTIONDURINGTHEPRODUCTIONDESIGNPHASEWILLELIMINATETHENECESSITYFORMOSTOFTHISTYPEOFCHANGETHEMORECOMMONTYPEOFCHANGETHEOCCURSAFTERMANUFACTURINGSTARTSISTHERESULTOFTHEAVAILABILITYOFNEWMATERIALSTHESE,OFCOURSE,PRESENTPOSSIBILITIESFORCOSTREDUCTIONANDIMPROVEDPERFORMANCEHOWEVER,NEWMATERIALSMUSTBEEVALUATEDVERYCAREFULLYTOMAKESURETHATALLTHEIRCHARACTERISTICSAREWELLESTABLISHEDONESHOULDALWAYSREMEMBERTHATITISINDEEDRARETHATASMUCHISKNOWNABOUTTHEPROPERTIESANDRELIABILITYOFANEWMATERIALASABOUTTHOSEOFANEXISTINGONEALARGEPROPORTIONOFPRODUCTFAILUREANDPRODUCTLIABILITYCASESHAVERESULTEDFROMNEWMATERIALSBEINGSUBSTITUTEDBEFORETHEIRLONGTERMPROPERTIESWEREREALLYKNOWNPRODUCTLIABILITYACTIONSHAVEMADEITIMPERATIVETHATDESIGNERSANDCOMPANIESEMPLOYTHEVERYBESTPROCEDURESINSELECTINGMATERIALSTHEFIVEMOSTCOMMONFAULTSINMATERIALSELECTIONHAVEBEENAFAILURETOKNOWANDUSETHELATESTANDBESTINFORMATIONAVAILABLEABOUTTHEMATERIALSUTILIZED；BFAILURETOFORESEE,ANDTAKEINTOACCOUNTTHEREASONABLEUSESFORTHEPRODUCTWHEREPOSSIBLE,THEDESIGNERISFARTHERADVISEDTOFORESEEANDACCOUNTFORMISUSEOFTHEPRODUCT,ASTHEMHAVEBEENMANYPRODUCTLIABILITYCASESINRECENTYEARSWHERETHECLAIMANT,INJUREDDURINGMISUSEOFTHEPRODUCT,HASSUEDTHEMANUFACTURERANDWON；ETHEUSEOFMATERIALSABOUTWHICH3THEREWASINSUFFICIENTORUNCERTAINDATA,PARTICULARLYTOITSLONGTERMPROPERTIES；DINADEQUATE,ANDUNVERIFIED,QUALITYCONTROLPROCEDURES；ANDEMATERIALSELECTIONMADEBYPEOPLEWHOARECOMPLETELYUNQUALIFIEDTODOSOANEXAMINATIONOFTHEFAULTSABOVEWILLLEADONETOCONCLUDETHATTHEEISNOGOODREASONWHYTHEYSHOULDEXISTCONSIDERATIONOFTHEMPROVIDESGUIDANCEASTOHOWTHEYCANBEELIMINATEDWHILEFOLLOWINGTHEVERYBESTMETHODSINMATERIALSELECTIONMAYNOTELIMINATEALLPRODUCTLIABILITYCLAIMS,THEUSEOFPROPERPROCEDURESBYDESIGNERSANDINDUSTRIESCANGREATLYREDUCETHEIRNUMBERSFROMTHEPREVIOUSDISCUSSION,ITISAPPARENTTHATTHOSEWHOSELE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