美国主办第一届激光冲击强化会议PPT(9)_报告者：韩国

GGwangjuwangjuIInstituteofnstituteofSScienceandcienceandTTechnologyechnologyLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.TheFirstInternationalConferenceonLaserPeeningDec.15-17,2008,Houston,TXLaserPeeningofDuplexStainlessSteelfortheEnhancementofSurfaceHardnessP.K.Kim,J.B.Park,J.H.Lee,M.H.Lee,andS.H.Jeong*DepartmentofMechatronicsGwangjuInstituteofScienceandTechnologyGwangju,RepublicofKoreaGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.2/19MotivationBalancepositionBalancebush¾Seawaterdesalinationusingreverseosmosisneedsahigh-capacityhigh-pressure(HCHP)pump(e.g.Flowrate:1573m3/hr)¾Toavoidcorrosion,duplexstainlesssteelischosenasthepumpmaterial¾Problemsofrotatingparts:Frictionwear/Stiction¾Improvementofsurfacehardnessoftherotatingparts(ring,sleeve,orbush):ReducereplacementneedsandSavemaintenancecostPumpdrawingofseawaterplantshaftGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.3/19PhotographsoftherotatingpartsofaHCHPpumpRotatingComponents¾Hardeningofsurface:Extendslifetimeofreplacementparts¾Differentiatinghardnessofcontactingsurfaces:Reducestiction100mmSurfacesforintendedhardeningGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.4/19Duplexstainlesssteel:Austenitic-FerriticstainlesssteelGeneralProperties¾Highstrength¾Goodresistancetopittingandcrevicecorrosion¾Highresistancetostresscorrosioncrackingandcorrosionfatigue¾Goodresistancetouniformcorrosion¾Gooderosionresistance¾Goodfatigueresistance¾Highenergyabsorption¾Lowthermalexpansion¾Goodweldability()Majoralloyingelements:-IncreasedCr:18-28%-ReducedNi:4.5-8%GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.5/19Duplexstainlesssteel2205duplex¾Typicalcomposition:Cr22%andNi5%,N0.15-0.25%¾Mostwidelyusedduplex¾ExcellentcorrosionresistanceandhighstrengthAtomCMnSiPSCrNiMoNIron%0.021.890.280.030.0122.645.483.070.16Bal.Experimentalsample¾GayaSteelCo.,KoreaGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.¾Examinethepossibilityofsurfacehardeningbylaserpeeningof2205duplexstainlesssteel•Performlaserpeeningatdifferentconditions•MeasurethemicroVickershardness6/19ObjectivesGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.7/197/18ExperimentalsetupWater4mmdeepd=12mmf=460mmEp,max=1.46J,τ=8ns,λ=532nmLinearpolarizationMultimode(~80%flat)GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.8/19SamplepreparationSize(mm)50W×50D×10HSurfacePolished(Roughness:30-60nm)CoatingmaterialCu(95%+H2O4%)Fe(95%+H2O4%)Al(15μmfoil,Commercial)Coatingthickness20-40μm/100-130μm-Bakedfor5minat110°CHardnessmeasurementMicro-Vickers(AakashiAAV-501)-Weight:100gGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.9/19Experimentalparameters¾Laserfluence,F(mJ/mm2)⇒150,200,250,300,8000.65×D(D=diameter)Scanspeed(v)¾Beamoverlapping[pulse/mm2][=Rep.rate×(D/v)/A]⇒1,10,20,30¾Totalirradiationarea:10mm×10mmGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.MicroVickersResults•Coated(Cu)samplevs.Non-coatedsample•Laserfluence(200,250,300mJ/mm2)–Pulseenergy:1.4J(fixed)–Spotdiameterchanged:3.0,2.7,2.4mm10/19GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.11/19Experimentalresults(HV0.1)102030300310320330340350HardnessOverlapping¾Nopeening(Ave.)¾Laserintensity200mJ/mm2andnocoating(spotd=3mm)¾Polished2μmforHV11%↓4%↓4%↓11%↑7%↑10%↑102030300315330345HardnessOverlapping¾Nopeening(Ave.)¾Laserintensity250mJ/mm2andnocoating(spotd=2.7mm)¾Polished2μmforHVGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.102030345360375HardnessOverlappingExperimentalresults(HV0.1)1%↑6%↑1%↑¾Nopeening(Ave.)¾Laserintensity300mJ/mm2andnocoating(spotd=2.4mm)¾Polished2μmforHV102030330345360375HardnessOverlapping¾Nopeening(Ave.)¾Laserintensity200mJ/mm2andCu(100μm)coating¾NopolishingforHV1%↓2%↓4%↑GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.¾Nopeening(Ave.)¾Laserintensity300mJ/mm2andCu(100μm)coating¾NopolishingforHV102030315330345HardnessOverlappingExperimentalresults(HV0.1)1%↑2%↑6%↑102030330345360HardnessOverlapping4%↓4%↓1%↓¾Nopeening(Ave.)¾Laserintensity250mJ/mm2andCu(100μm)coating¾NopolishingforHVGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.Experimentalresults(HV0.1)¾Laserintensity250mJ/mm2Overlapping30¾WhenCulayerexists,thereisnochangeofsurfaceroughness¾Nocoating¾F=250mJ/mm2¾Overlapping(pulse/mm2):30¾Surfacebecomeroughnessfrom30nmto150nm¾PolishingrequiredforHVGGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.MicroVickersResults•Differentcoatingmaterial:Cu,Fe,Alfoil•Elevatedlaserfluence(max.irradiance=~10GW/cm2)•Increasedspotarea(d=3.5mm)15/19GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.ParametersFluence(mJ/mm2)800Thickness(μm)~100(Cu/Fe)~20(Cu/Fe/Al)Experimentalresults(HV0.1)Afterlaserpeening(Cucoating)Almostnochange¾Cucoating(~100μm)¾F=800mJ/mm2¾Overlapping1.7(spotd=1.5mm)GGISTISTLLaseraserMMicro/icro/NNanoanoFFabricationLab.abricationLab.~8%↓3%↑¾