測定淬火槽對流強(qiáng)度的熱流速儀探頭的優(yōu)化設(shè)計(英文).docx

1、(3)沖頭表層硬度高， 而過渡區(qū)硬度降低.這種強(qiáng)韌組合使沖頭具有較高的抗沖擊性、耐精性，使用壽命提高407.2胡昭如.機(jī)械工程材料：M.長沙：中南工業(yè)大學(xué)出版社.1991.3:70-80.3石世宏激光堵工藝與粉末對鼠層開裂行為的影響：JL金屬熱姓理,1998.23(9):31-32.4黃SLT12A鋼蛭刀的組織與壽命研究J.金 X 烘處理.1998.23(8):3233.：5張定夷.Crl2鋼淬火軟點(diǎn)形成原因及防止措fifefj.金屬熱處理.1998,23(9):27-30.SensorTipOptimizationforaThermalAnemometerforDeterminingConv

2、ectionIntensityinQuenchBathsH.M.Tensi1,A.Haas1,K.Lainer1,G.E.Totten2,G.M.Webster2(1.DepartmentofMaterialsandProcessing,TechnicalUniversityofMunich,Germany;2.TheDowChemicalCompany,Tarrytown,NY10591)Abstract：Duetotheoccurrenceofcomplexfluidflowpatternsinaquenchtankwhichwillsignificantlyimpacthardening

3、results,itisimportanttodevelopacompactflowmeasuringdevice.Atypicalquenchprocessinvolvesimmersionofaustenitizedsteelintoaquenchbathwhichaffectsthecirculationofthefluidandresultsinnon-uni-formflowandthermalstriationsinthequenchant.Thisnon-uniformityoffluidflowpatternsthereforeresultsinvariationsofheat

4、transferandsubsequentinconsistenthardeningoftheparts.Inthispaper,thesystematicoptimizationofthetipofathermalanemcxneterusedtomeasureflowratesinaquenchtankarereviewed.測定淬火槽對流強(qiáng)度的熱流速儀探頭的優(yōu)化設(shè)計摘要摘要:淬火槽中復(fù)柴的液流形態(tài)會明顯影響淬硬結(jié)果.因此開發(fā)一套結(jié)構(gòu)緊湊的液流測量裝置就顯得很重要一個典型的淬火過程包括把已奧氏體化r的鋼袖沒在淬火槽中，這一過程勢必影響液流的循環(huán)，使其形成不均勻的液流和熱波動，由此而引起傳熱

5、變化,導(dǎo)致零件的不均勻淬火。本文介紹r用于測酸淬火槽中液流速率的熱風(fēng)儀探頭的系統(tǒng)優(yōu)化設(shè)計。中圖分類號:TG155.3文獻(xiàn)標(biāo)識碼：A文章編文章編:0254-6051(2002)07-0039-061IntroductionThesuccessofaquenchingpnxssisdependentonheattransferduringdifferentphasesofcooling,particularlyduringanimmersionquenchingprocess.Itiswellknownthattheoverall 注：本文由國際炊處理和表面工程聯(lián)合會(1FHTSE)主席、本刊高級

6、顧f5)Phl)G.E.Totten(l；SA)先生供稿.其中中文內(nèi)容是編皆后加的.僅供參與E-mail：tottcngcdow.a)m收稿日期2001-1031coolingprocessmaybeaffectedbyagitation,panicularlylocalizedflowratevariation,andinthecaseofaqueouspolymerquenchants,bathtemperature.Quenchingmediasuchasthosebasedonpetroleumoilsoraqueouspolymersolutionsmayalsobesignific

7、antlyimpactedbyfluiddegradationandcontamination.Thereforetoavoidtheundesirableconsequencesoftheseeffectsandtoprovideadequatecontrolofthequenchingprocess,itisimportanttobeabletocharacterizetheoverallheattransferprocessinthequenchtankduringthequenchingprocess.(Mdifferentvariables.oneofthenxtchallcngin

8、g(andniriant)isthedetenninationoflocalizedflowratevaria-lioninthelankandthroughouttheload.Thiswillnecessitatethedfvelopnwntofaflowmeasuringprobetodetectlocalizedvariationsinflowaridpotentiallypermitsubsequentadjustmentoftheheattranferprojx*rtie5ofthequenchanttoobtainthedesiredmetallurgicalresults.試樣

9、使用時間/h硬度(HRC)磨損母/mmMl39566-670.145M238965670.147N122056-590.15N221056-600.15N322055-600.149N1022055-590.151圖4過渡區(qū)金相組織1000Fig.4Thernicnjstnxtureoftransitionzoneofsamplex1000轉(zhuǎn)速為877r/min.沖頭每轉(zhuǎn)一轉(zhuǎn)，工作一次。試樣使用時間對比如表2：工作長度為L.當(dāng)磨損最0.15mm時.則沖頭報廢。4 結(jié)論(1)GCrl5鋼藥物沖頭激光表面淬火時，本試驗條件下,表層單位所需能址為3OJ/mm2最好，這時硬度明顯升高。(2)表面激光淬

10、火后.表層為細(xì)小馬氏體、 隱晶馬氏體和彌散分布的大小不一的合金碳化物.這種組織耐磨性非常好。表表2試樣使用時間與磨損Table!Theservicetimeandwearlossoftestpieces參考文獻(xiàn)：參考文獻(xiàn)：1孫家樞金屬的麟攬MJ.北京：冶金工業(yè)出版社.1992.10:404.Ioaddrvssthisproblem,aprojectwasundertakentodesignaflowthermalanenxMiieter.Th*reportdescribestheef-kvtofnicasuringtipgeonntryi)nthemeasurenKntoffluidflowr

11、ato.2Discussion2.1PrinciplesofOperationI、definecoolingpowerinproductionquenchingtanks,(heux?oflinearfluidvelocityisnothelpfullx?causeflowdirectionmidiwistan*notdefined.FulldefinitionofcoolingpowerrequiresnieaurenjcntofcoolingbehaviorofthepartatdifferentpositionsduringthecjuenchingprocessasshowninFig

12、ure1.Forexample,detemiinHiionofoolirigpowerinsideofaringorabasketofnmUp/rismaylx-determinedaldifferentpositionsaroundthepart、uingaprobesuchasthatillustratedinFigure2.Applying(hex*principle,thepnjbeillustratedinFigure3wasdevelqxxitorecurJf(heprobe*.Fig-1Schemalieofanagitatedindustrialquenchingtankwit

13、hdifferentkindsofpan、andtheprobeusedtoquantifythequenchingpoweratdifferentlocationsinthetank圖1不同零件在帶攪拌的L業(yè)淬火槽中淬火并用探頭測城槽中不同位置的淬火能力Apn)besimilartotheprobeillustratedinFigure2hasre-cendyIKEdeveloped-.Thisprobemeasuresheatfluxfromtheparitothesurroundinxquenchantwithanunknownflowveh)cityandanunknownturbul

14、enceortwist.TheprobegeometryIvisIxtndesignedtominimizedependenceonflowdirectionandsiillbehighlysensitivetoagitation.ThebodyoftheprobehasafrodydefinedtemperatureTfthatfulfillstheconditions：Tkuiwiffz/T(1)andr=constant(2)Fig.2Schematicoftheprobeusedtodefinetheagitationpowerofaquenchingbathwithforcedcon

15、vectionandtheenergybalance圖2用探頭泌量帶有強(qiáng)制對流和熱平衡的淬火槽的攪拌能力Fig.3Illustrationoftheheal-basedflowprobe圖3熱絲法液流探頭示意圖byvariationofconductedenergy.Thisprobepermitsmeasurementsofdeliveredenergyaccordingtotheequation：=constant(3)BecausethedeliveredenergyEartsuitableforthemeasurementoflowvelocitiesduetotheirhightem

16、peraturecoefficientsandassociatedhighoutputsignals.【hmeasurementsensorisheateddwtrically.AstateofequilibriumisreachedincorrespondencewiththecoolingconditionsThetemperatureofthemeaurenientsensorpresentinthestateofequilibnumdeterminestheresistance.Appropiiatecircuitryderivesasignalfromthisroistance.an

17、dsuitableneaun-menltechnologythenevaluateslhesignal.Thermalmeth(xlsinvcveheatingthemediumtobvsured.Theheatbalancecanthenbeusedtocalculatethenias?throughputandthustheflowvelocityofthemediumfromthuamountofheatingpowersuppliedtoincreasethetenipcraiureofthefluidandthespecificheatcapacityofthefluid.Sever

18、alpotentialmethodsforheatingtheflowprobewereexaminedbeforechoosinganeffidentandeconomicalmethcxlofusingaheatingcartridge.Arelativelylargeamountofheatcanbegeneratedinaverysmallspacebythesecomponents.2.2ExperimentalHeatingcartridgesconsistofresistancewiresinstalledinsideametaljacket.Thewiresareprotect

19、edagainstdamagebyintrinsicheatingbyinsulatedceramicfill.Heatistransferredbythermalconductionthrough(hemetaljackettoabodyincontactwiththeflowingfluid.Thisrelativelyloss-freeenergytransferpermitsreductionoflheelectricpowerrequiredfortheflowprobe.Anemometerprobetipdesignsthatwerecvaluatuxlareillustrate

20、dinFigure5.Toevaluatethedynamicsoftheprobewithrespecttotheheatingraleofthecartridgeandtheflowofheattotheprobetip,aconstantvoltagewasappliedtotheheatingcartridgebymeansofavoltammeterwhilethechangesintemperature(measuredwiththermocouples)attheprobetipandinlheflowchannelwereruonitored.Anillustrationoft

21、heapparatususedfortheseexperimentsisshowninFigure6.Agitationwassuppliedusingapropellerconnectedtoavanablespeedelectricmotor.Thepropellerspeedwassettoaconstantvaluethatisdirectlyproportionaltothelocalflowvelocitythatwasdeterminedbymeansofanopto-electronictachometer.Anelectricalvoltagewasappliedtotheh

22、eatingcartridgeuntilthetemperaturedifferencebetweenthefluidintheexpcrirmii-talbathandtheprobetiphadreaclxfdthedesiredvalueandequi-arFig.5Anemometerprobetipdesigns圖5流速儀探頭端部的結(jié)構(gòu)lectEA-Blibratedasdisplayedaithetemperature-measuringinstrument.Thepowerappliedto(heheatingelementandtemperaturevalueswere(hen

23、recorded.Ihus,a(aconstanttemperaturedifferenceTgetip-Tbth，thevaluefortheheatingpowerassociatedwiththeselectedrotationalspeedwasobtained.Thetemperaturedifferencewaskeptconstant.ThepowerconsumptionbehaviorcurvesthatwereobtainedwiththedifferentanemometerprobetipsillustratedinFigure5usingtheapparatussho

24、wninFigure6areprovidedinFigures7and8.海布FTZTBAcwvratak/ms-Fig.7Powerconsumptionbehavioroftheprobe(ipversusflowrateofwalerasafunctionof：(a)temperaturemeasurementsiteinthetip;(b)temperaturedifference(l);(c)shapeofthelip;(d)orientationtothedirectionofflow(hemisphericaltip);and(c)orientationtothedirectio

25、nofflow(spiraltipdiffuser)圖7以下情況對水流速率和探頭虎能關(guān)系的影響(a)頂端溫度測地位置(b)沮差(c)頂端的形狀（d）液流方向（半球狀頂端）（e）液流方向（螺旋形儂端擴(kuò)散體）3Results()n(hebasisofinitialconsiderations.itwasconcludedthatasphericalgeometrywouldbelikelytoexhibitheattransferbehaviornearlyindependentofflowdirection.However.itisimpossibleiownstructasensorheadw

26、ith(heidealperfectlysphericalshape.Heatextractedfromthesensorheadbytheflowingliquidmustbesuppliedtotheheadviatheshaftoftheprobe.Thecross-sectionoftheshaftofthesensorheadmustbebigenoughtoconducttherequiredthremalcurrenttothetipoftheprobe.Thesefactorsrequireaconnectionwiththecross-sectionthatisapproxi

27、matelythesameasthecross-sectionofthesphericalgeometryofthemeasuringtip.Thisreducestheidealsphericalshapeofthemeasuringtip(othegeometryofahemisphere.Toconductpreliminaryexperimentalstudies,twohemisphericalsensortipswithdiametersof2.5and4.()minwereproduced.Tosuppresstheheattransferfn1m/s,thetwopowercu

28、rvesexhibitincreasingdifferencesbetweenthem.Onthebasisofthiswork.itisconcludedthataprobebodywithaconeangleof90andwithdimensionsshowninFigure5fortipS8canbeconsideredtorepresentidealprobegeometry.4SummaryTooptimizeheattreatmentperformanceitisnecessarytominimizelocalizedflowrategradientsincommercialque

29、nchtanlo.Theselocalizedflowvariationsmaybemeasuredusingthermalanemexnetry.Thispaperdescribedtheuseofthermalanemometrytoexaminethepowercurvesofdifferentflowgeometriesintheflowraterangeof0.32.6m/s.Theperformanceofindividualtipgeometrieswerethenevaluatedonthebasisofthefollowingcriteria:,Maximumamountof

30、electricpowerconsumed,Riseofthepowercurve.Dynamicbeliaviordthelipandlackofdependenceoftheflowangle.Toimpnweperformancewithrespecttotheabovecriteria,designchangesinthepnbetipandbodyduringdiepreliminaryexperimentationwasperformed.Thefollowingvariableswerefoundtoexhibitverysignificanteffects：,Insulatio

31、noftheprobeslxaft. Locationofthetemperaturemeasurementsiteintheprobebody. Geometryofthetip.Theexperimentalstudiesreportedhereshowthattheconicalprobetipwithaa)neangleof90,andaninsulatedprobeshaftws5themobtsuitablemeasurementtipgeometryforthiscase.Theselectedprobeshapeperformsbetterinthisapplicationth

32、ananyoftheothertestedgeometriesanditalsoexhibitsapoweruptakewhichisindependentofflowdirectionovertheentireflowraterange.Theprobedynamicsachievablewiththistipgeometrythelengthoftimethatittakestoachieveasteadystatetemperaturedifferenced/=3K)intheprobebodyisexcellent.Withinthescopeofthiswork.ithasbeend

33、emonstratedthatitispossibletovalidateexperimentallythataconicaltipcanbeusedtomakereliablemeasurementsofthelocalizedflowratesinanyindustrialquenchingfluid.References：1G.E.Totten.H.MTensi.andT.Kunzel.PhysicsandTechnologyofQuenchingFluidsPanU:TechnologyofQuenchingin20thHeatTreatingSocietyConferenceProceedings.Eds.K.EunataniandG.E.Totten,ASMInternational.MaterialsPark.OH,1999,p.731-736.2H.M.Ten,G.E.TottenandG.M.Webster.ProposaltoMonitor.girationofProductionQuenchTanks*.in17thHeatTreatingSocietyCon