Metal Terminology (P)金属术语P

PACKROLLING
Rollingtwoormorepiecesofthinsheetatthesametime,amethodusuallypracticedinrollingsheetintothinfoil.

PASS
Atermindicatingtheprocessofpassingmetalthrougharollingmill.

PATENTING
Treatmentofsteel,usuallyinwireform,inwhichthemetalisgraduallyheatedtoabout1830癋,withsubsequentcooling,usuallyinair,inabathofmoltenlead,orinafusedsaltmixtureheldbetween800癋and1050癋.

PATENTLEVELING
(SeeStretcherLeveling)

PATTERNEDOREMBOSSEDSHEET
Asheetproductonwhicharaisedorindentedpatternhasbeenimpressedoneitheroneorbothsurfacesbytheuseofrolls.

PEARLITE
Lamellarstructureresemblingmotherofpearl.Acompoundofironandcarbonoccurringinsteelasaresultofthetransformationofausteniteintoaggregationsofferriteandironcarbide.

PERMALLOY
Nickelalloyscontainingabout20to60%Fe,usedfortheirhighmagneticpermeabilityandelectricalresistivity.

PERMANENTSET
Non-elasticorplastic,deformationofmetalunderstress,afterpassingtheelasticlimit.

PHOSPHORBRONZE
Copperbasealloys,with3.5to10%oftin,towhichhasbeenaddedinthemoltenstatephosphorousinvaryingamountsoflessthan1%fordeoxidizingandstrengtheningpurposes.Becauseofexcellenttoughness,strength,finegrain,resistancetofatigueandwear,andchemicalresistance,thesealloysfindgeneraluseasspringsandinmakingfittings.Ithascorrosionresistingpropertiescomparabletocopper.

PHOSPHORBRONZESTRIP
Acopper-basedalloycontainingupto10%tin,whichhasbeendeoxidizedwithphosphorousinvaryingamountsoflessthan1%(seePhosphorBronze).Temperisimpartedbycoldrolling,resultingingreatertensilestrengthandhardnessthaninmostcopper-basealloysoreitherofitsalloyingelementscopperortin.Thevarioustempersfrom“OneNumberHard”to“TenNumbersHard”areclassifiedinhardnessbythenumberofB&SGagesreductionindimensionfromtheprevioussoftorasannealedstate(SeeBrown&SharpeGages).PhosphorBronzeisnotheattreatableforpurposesofhardnessdevelopment.Itdoesnotwithstandelevatedtemperaturesverywellandshouldnotbeusedinserviceabove225癋.evenafterstressrelievingtreatmentat325to350癋.Ithasexcellentelectricalproperties,corrosionresistantcomparabletocopper;greattoughnessandresistancetofatigue.Ratedgoodforsoftsoldering,silveralloybrazing,oxyacetylene,carbonarcandresistancewelding.

PHOSPHORUS
(ChemicalsymbolP)-ElementNo.15oftheperiodicsystem;atomicweight30.98.Non-metallicelementoccurringinatleastthreeallotropicforms;meltingpoint111癋.;boilingpoint536癋.;specificgravity1.82.Insteelsitisusuallyundesirablewithlimitssetinmostspecifications.However,itisspecifiedasanalloyinsteeltopreventthestickingoflight-gagesheets;toadegreeitstrengthenslowcarbonsteel;increasesresistancetocorrosion,andimprovesmachinabilityinfree-cuttingsteels.InthemanufactureofPhosphorBronzeitisusedasadeoxidizingagent.

PHOTOMICROGRAPH
Aphotographicreproductionofanyobjectmagnifiedmorethantendiameters.Thetermmicrographmaybeused.

PHYSICALPROPERTIES
Thosepropertiesfamiliarlydiscussedinphysics,exclusiveofthosedescribedundermechanicalproperties;forexample,density,electricalconductivity,co-efficientofthermalexpansion.Thistermoftenhasbeenusedtodescribemechanicalproperties,butthisusageisnotrecommended.(SeeMechanicalProperties)

PICKLING
Theprocessofchemicallyremovingoxidesandscalefromthesurfaceofametalbytheactionofwatersolutionsofinorganicacids.

PICKLINGPATCH
Adefectintinplate,galvanizedorterneplatedsteelduetofaultypickling,leavingareasfromwhichtheoxidehasnotbeencompletelyremoved.

PIGIRON
Ironproducedbyreductionofironoreinablastfurnace.Pigironcontainsapproximately92%ironandabout3.5%carbon.Thebalanceislargelysiliconeandmanganesewithasmallpercentageofphosphorus,sulphur,andotherimpurities.

PINCHPASSTEMPER
(SeeSoftSkinRolledTemperand/orTemperRolling)

PINCHERS
Longfernlikecreasesusuallydiagonaltothedirectionofrolling.

PINHOLES
Microscopicimperfectionsofthecoatings,thatis,microscopicbarespots,alsomicroscopicholespenetratingthroughalayerorthicknessoflightgagemetal.

PIPE
(Defect)-Contractioncavity,essentiallycone-likeinshape,whichoccursintheapproximatecenter,atthetopandreachingdownintoacasting;causedbytheshrinkageofcastmetal.

PIT
(Defect)-Asharpdepressioninthesurfaceofthemetal.

PLANIMETRICMETHOD
Amethodofmeasuringgrainsize,inwhichthegrainswithinadefiniteareaarecounted.

PLASTICDEFORMATION
Permanentdistortionofamaterialundertheactionofappliedstresses.

PLASTICITY
Theabilityofametaltobedeformedextensivelywithoutrupture.

PLATING
Athincoatingofmetallaidonanothermetal.(SeeElectroplating,Galvanizing,TinningandTinplating)

POLISHEDSURFACE
(BuffedSurface)-Thefinishobtainedbybuffingwithrougeorsimilarfineabrasive,resultinginahighglossorpolish.

POLYMORPHISM
Theabilityofamaterialtoexistinmorethanonecrystallographicstructure.Numerousmetalschangeincrystallographicstructureattransformationtemperaturesduringheatingorcooling.Ifthechangeisreversible,itisallotropy.Theallotropyofiron,particularlythechangesbetweenthealphabody-centeredandthegammafacecenteredform,isoffundamentalimportanceinthehardeningofsteel.

POT
Avesselforholdingmoltenmetal.Alsousedtorefertotheelectrolyticreductioncellemployedinwinningcertainmetals,suchasaluminum,fromafusedelectrolyte.

POTANNEALING
IsthesameasBoxAnnealing.

POURING
Thetransferofmoltenmetalfromtheladleintoingotmoldsorothertypesofmolds;forexample,incastings.

POWDERMETALLURGY
Theartofproducingmetalpowdersandofutilizingmetalpowdersfortheproductionofmassivematerialsandshapedobjects.

PRECIPITATIONHARDENING
Aprocessofhardeninganalloyinwhichaconstituentprecipitatesfromasupersaturatedsolidsolution.(SeealsoAgeHardeningandAging)

PRECIPITATIONHEATTREATMENT
Anyofthevariousagingtreatmentsconductedatelevatedtemperaturetoimprovecertainofthemechanicalpropertiesthroughprecipitationfromsolidsolution.(SeeArtificialAging,InterruptedAging,andProgressiveAging)

PREHEATING
(1)Ageneraltermusedtodescribeheatingappliedasapreliminarytosomefurtherthermalormechanicaltreatment.(2)Atermappliedspecificallytotoolsteeltodescribeaprocessonwhichthesteelisheatedslowlyanduniformlytoatemperaturebelowthehardeningtemperatureandisthentransferredtoafurnaceinwhichthetemperatureissubstantiallyabovethepreheatingtemperature.(3)Heatingametaltoarelativelyhightemperatureforarelativelylongtimeinordertochangethestructurebeforeworking.Ingotsarehomogenizedbypreheating.

PRIMES
Metalproducts,suchassheetandplate,ofthehighestqualityandfreefromvisiblesurfacedefects.

PROCESSANNEALING
Inthesheetandwireindustries,aprocessbywhichaferrousalloyisheatedtoatemperaturecloseto,butbelow,thelowerlimitofthetransformationrangeandissubsequentlycooled.Thisprocessisappliedinordertosoftenthealloyforfurthercoldworking.

PROGRESSIVEAGING
Anagingprocessinwhichthetemperatureofthealloyiscontinuallyincreasedduringtheagingcycle.Thetemperaturemaybeincreasedinstepsorbyanyotherprogressivemethod.

PROPORTIONALLIMIT
Thegreateststressthatthematerialiscapableofsustainingwithoutadeviationfromthelawofproportionalityofstresstostrain.(Hooke’sLaw)

PUNCH
Themovablepartthatforcesthemetalintothedieinequipmentforsheetdrawing,blanking,coining,embossingandthelike.

PUNCHING
Shearingholesinsheetmetalwithpunchanddie.

PYROMETER
Aninstrumentofvarioustypesusedformeasuringtemperatures.