激光熔覆新型Co基合金組織及擦傷性能研究Studyof

MicrostructureandAbrasionResistanceofNovelCo-BasedAlloyLaserCladdingCoatings辯論人：任方成Candidate:RenFangcheng導(dǎo)師：姚建華教授Advisor:Prof.YaoJianhua時(shí)間：2023.5.26激光先進(jìn)制造研究院目錄(contents)1研究背景及意義(Backgroundandsignificance)2Co基合金熔覆工藝與組織研究(Microstructure)Co基合金熔覆層的性能分析(Performance)3閥門密封面應(yīng)用研究(Application)4結(jié)論與展望(Conclusionsandprospects)5一研究背景及意義(Backgroundandsignificance)煤制油化工閥門工況要求(Coalliquefactionprocess)

直接液化Directliquefaction間接液化Indirectliquefaction①430~470℃②17~30MPa①350℃②2-3MPa④由H2S,NH3,H2,CO,O2,Cl-等腐蝕性物質(zhì)引起的腐蝕(Corrosion)⑤流體介質(zhì)中大量硬質(zhì)顆粒造成的磨損、(Wear,abrasioncausedbymassivehardparticlesfromliquidphase)擦傷失效Failure③沖蝕，氣蝕(Erosion,cavitation)擦傷HVOF工藝外表堆焊工藝(Welding)ENP(化學(xué)鍍鎳磷合金)工藝優(yōu)點(diǎn)：效率高，得到高性能涂層(Advantages:Highefficiency)缺點(diǎn)：涂層結(jié)合力弱，涂層薄(Disadvantages:Lowbondingstrength)優(yōu)點(diǎn)：經(jīng)濟(jì)性好，技術(shù)門檻低(Advantages:Higheconomicefficiency)缺點(diǎn)：稀釋率大，熱影響區(qū)大(Disadvantages:Higherdilutionrate)優(yōu)點(diǎn)：大批量生產(chǎn)，涂層性能穩(wěn)定均勻(Advantages:Uniformproperties)缺點(diǎn)：涂層薄，結(jié)合力較弱(Disadvantages:Thincoating,lowbondingstrength)

相比以上工藝，激光熔覆技術(shù)具有涂層結(jié)合力強(qiáng)，涂層厚度可控，稀釋率小，熱影響區(qū)小。(Strongbonding,lowerdilutionrate,adjustablecoatingthickness)激光熔覆工藝(lasercladding)存在問(wèn)題：高硬度、耐磨損、耐腐蝕合金粉末大面積應(yīng)用易出現(xiàn)裂紋，孔洞等缺陷。(Problems:Crackinginthehighhardnesscoatings)優(yōu)點(diǎn)(Advantage)：一研究背景及意義(Backgroundandsignificance)一研究背景及意義(Backgroundandsignificance)激光熔覆Co合金粉末沿用熱噴涂粉末，主要類型有：Thermalspraypowder:研發(fā)本錢低，且大面積應(yīng)用時(shí)無(wú)裂紋、內(nèi)部缺陷出現(xiàn)的高性能激光熔覆用粉末是激光熔覆材料技術(shù)的難點(diǎn)。Challengeoflasercladding:Nocrackinginlarge-areacoatingsandlowR&DcostsCo基自熔性合金粉末(Co-basedselffluxingalloy)金屬基/陶瓷復(fù)合粉末(Compositepowderofceramicsandmetal)Co基非自熔性合金粉末(Co-basednonselffluxingalloy)粉末研發(fā)本錢高；高性能涂層易出現(xiàn)開(kāi)裂、外表或內(nèi)部缺陷問(wèn)題。(HighcostsinR&D;Crackingfoundincoatings)成型能力、造渣能力及對(duì)熔池的保護(hù)差。(Poorweldpoolprotection)硬質(zhì)顆粒在潤(rùn)濕性、穩(wěn)定性及熱膨脹系數(shù)方面的不同導(dǎo)致力學(xué)性能不均勻。(Non-homogenousmechanicalpropertiescausedbydifferentcoefficientsofthermalexpansion)一研究背景及意義(Backgroundandsignificance)課題的意義和創(chuàng)新點(diǎn)(Significance

and

innovation)獲得了熔覆層在碳含量降低與Mo元素增加后的組織與耐磨性的變化規(guī)律；制備新型Co基高性能激光熔覆層克服了高硬度Co基合金大面積應(yīng)用時(shí)易裂的技術(shù)瓶頸。(DevelopmentofnovellasercladdingStellitealloypowderwith70wt%high-carbonStellitealloyplus30wt%lowcarbonStellitealloytoreducecrackinginthecoatinglayer.)采用自動(dòng)劃痕儀進(jìn)行單點(diǎn)劃痕模擬防止了傳統(tǒng)閥門擦傷試驗(yàn)必須在進(jìn)行實(shí)體閥門開(kāi)關(guān)閉測(cè)試的限制。對(duì)劃痕深度、加工硬化特性，切向力與劃痕形貌進(jìn)行了分析。(Thisnovelcoatinghasbeenappliedonthesealingsurfaceofballvalvesandbutterflyvalves.Theperformanceofthecoatingisinvestigatedunderworkhardeningtest.)激光熔覆專用合金粉末的調(diào)配(Specialpowderpreparation)優(yōu)化工藝參數(shù)：1不同粉末配比2工藝與涂層硬度3金相組織(Processparameteroptimization)單道多道搭接試驗(yàn)、制備試樣。進(jìn)行組織物相與性能的分析(Performanceanalysis)球閥、蝶閥實(shí)體熔覆與擦傷泄露測(cè)試。(Valvesealingsurfacelasercladding)本文的工作內(nèi)容(Workcontents)

二

Co基合金熔覆工藝與組織研究(Microstructure)煤制油閥門密封面工況特殊要求(Coalliquefactionprocess)需具有抗沖蝕、抗氣蝕與抗擦傷的能力(Erosion,cavitationandabrasionreisitance)抗H+、

H2S、Cl-腐蝕的能力(CorrosioncausedbyH+,H2S,Cl-)粉末的調(diào)配(Powderpreparation)numbermaterialsability1Co-Cr-Walloyexcellent217-4PHor17-7PHgood3SA182-F316orSA182-F316Lgood4Cr-Mosteelcommon5Castironcommon(Strongcarbide-formingelements)結(jié)合力強(qiáng)弱：Fe＜Mn＜Cr＜Mo＜WMo+Sprecipitation

AlloyCrWMoCFeNiSiMnHRCapplicationStellite330.512.5

-2.453.52260Valveseatetc.Stellite4301410.57332141Hotembossingmouldetc.Stellite628.54.51.51532240Enginevalveetc.Stellite12308.3

-1.431.50.72.542Sawtoothetc.Stellite2127

-5.50.2532.751128Turbinebladeetc.Stellite31227.5

-0.51.5100.50.531Turbinebladeetc.Stellite8033.519

-2.0-

-

-

-

52Bearingsleeveetc.AlloyCrWMoCFeNiSiMnHRCapplicationStellite330.512.5

-2.453.52260Valveseatetc.Stellite2127

-5.50.2532.751128Turbinebladeetc.合金的選擇(Selectionofalloy)：1、Co基合金

(Co-basedalloy)2、合金中需含有足夠的強(qiáng)化相〔碳化物等〕阻止擦傷(Enoughstrengtheningphasetopreventabrasion)Stellite3Co-Cr-WHighercarboncontent,higherhardnessWearandabrasionresistanceStellite21Co-Cr-MoLowercarboncontent,lowerhardness,betterworkhardeningRelativelylowwearresistanceNewalloyCo-Cr-W-MoGoodMacroscopicfeatureWearandabrasionresistanceHighhardness,workhardening二

Co基合金熔覆工藝與組織研究(Microstructure)Crackoccursinlasercladdingcoatings3、合金中需要強(qiáng)碳化物形成元素W、Cr去防止氫腐蝕的發(fā)生；Mo元素可以與S形成彌散析出物，削弱H2S腐蝕〔ThenewalloyneedscontainingW、MoandCrelement〕Nocrackformationinlasercladdingcoatings序號(hào)Stellite3Co-1Co-2Co-3層高層高層高層高1#4454755125362#4824685235323#4734955185504#7127397257935#7487747918206#7978108339207#1047116312201254編號(hào)功率kW掃描速度mm/min送粉量g/min比能kJ/cm21#0.61801052#0.8180105.833#1180106.664#1.23601355#1.4360135.836#1.6360136.667#1.8540165Stellite3:Stellite21=7:3(wt%)(Co-3)激光工藝優(yōu)化(Laserprocessoptimization)Stellite3Stellite3:Stellite21=9:1(wt%)(Co-1)Stellite3:Stellite21=8:2(wt%)(Co-2)Stellite3Co-3Co-2Co-17#1#(Coatinglayerheight)單層高度測(cè)試(μm)(Hardnesstest)硬度測(cè)試二

Co基合金熔覆工藝與組織研究(Microstructure)Stellite3Co-1Co-3Co-23#熔覆層6#熔覆層6#熔覆層3#熔覆層(Dilutionrate)稀釋率：55.1%(Dilutionrate)稀釋率：32%(Dilutionrate)稀釋率：33%(Dilutionrate)稀釋率：42%(Layerheight)高度：473μm(Layerheight)高度：495μm(Layerheight)高度：833μm(Layerheight)高度：920μmStellite21的逐漸增多(AdditionofStellite21)新合金中B、Si含量減少，熔點(diǎn)升高(DecreaseofB,Sicontent)熔池流動(dòng)性變差、黏度增大，熔融狀態(tài)不易外流(Liquidityvariation)稀釋率更小(Lowerdilutionrate)Stellite3Co-1Co-2Co-3優(yōu)化的參數(shù):(Optimalparameters)：Co-3合金(Stellite3:Stellite21=7:3)(wt%)6#

(功率:1600W,送粉量:13g/min,掃描速度:6mm/s)二

Co基合金熔覆工藝與組織研究(Microstructure)層高更高(Thickerlayer)激光工藝優(yōu)化(Laserprocessoptimization)較大面積的搭接試驗(yàn)(largeoverlapingtest)涂層顯微組織分析〔Microstructureanalysis〕Stellite3Co-3Co-2Co-1Stellite21的參加(AdditionofStellite21)新合金組織粗大(Coarsegrains)新合金中W含量減少,Mo含量增加(Wcontentdecreases,Mocontentincreases)W元素細(xì)化晶粒的能力強(qiáng)于Mo元素(WelementisbetterthanMoelementintheabilityofgrainrefinement)Co-3合金面掃秒分析(MapanalysisofCo-3)AreaCCrWMoFeCo15.2319.6120.975.806.35Bal.24.9625.3615.744.287.39Bal.39.2535.999.192.596.41Bal.123二

Co基合金熔覆工藝與組織研究(Microstructure)物相分析(Phaseanalysis)Stellite3Stellite21Co-3fcc-Co,(Co,W)6C,Cr7C3fcc-Co,Co7Mo6,Co3Mo,Cr23C6fcc-Co,(Co,W)3C,Co3Mo,Cr7C3,

Cr23C6Co-3合金灰色(gray):fcc-Co白色(white):(Co,W)3C,Co3Mo黑色(black):Cr7C3,

Cr23C6較高的W、Mo含量更容易形成(Co,W)6C,Co7Mo6(HigherW

andMocontentiseasiertoform(Co,W)6C,Co7Mo6)相反的，較低的W、Mo含量更容易形成(Co,W)3C,Co3Mo(LowerWandMocontenteasilyforms(Co,W)3CandCo3Mo)二

Co基合金熔覆工藝與組織研究(Microstructure)三

Co基合金熔覆層性能分析(Performance)摩擦磨損性能分析(Wearperformanceinvestigation)Stellite3Stellite21Co-3三種合金磨損體積(wearloss)摩擦系數(shù)曲線(Frictioncoefficientcurves)Stellite3Co-3Stellite21三

Co基合金熔覆層性能分析(Performance)摩擦磨損性能分析(Wearsurfaceanalysis)添加了Stellite21的Co-3合金中，Co3Mo阻礙磨損的作用與(Co,W)3C相似Co3Mophasehassimilareffectonwearresistanceto(Co,W)3Cphase.擦傷性能分析(Abrasionperformanceanalysis)最大載荷下的劃痕深度Indentationdepthatmaximumload:SS316:17.1μmCo-3:8.1μmSS316Co-3HardnessunchangedHardnessincreasedto835HV0.2ScratchgrooveSectionSS316Co-3HardnessunchangedHardnessincreasedto918HV0.2Plasticdeformationfcc-Cohcp-CoHardness劃傷影響區(qū)約為120μm，新型Co基合金存在加工硬化現(xiàn)象(Workhardeningphenomenoncanbefoundonnewalloycoatingsurface)加工硬化性能測(cè)試〔Workhardening〕三

Co基合金熔覆層性能分析(Performance)SS316與Co-3合金的劃痕深度隨載荷的變化IndentationdepthvariationswithloadincreaseforSS316andnewalloyStablestageSS316Co-3擦傷性能分析(Abrasionperformanceanalysis)三

Co基合金熔覆層性能分析(Performance)SS316Co-3擦傷性能分析(Abrasionperformanceanalysis)smallchangestageSS316Co-3三

Co基合金熔覆層性能分析(Performance)SS316Co-3largechangestageSS316Co-345°F90°三

Co基合金熔覆層性能分析(Performance)擦傷性能分析(Abrasionperformanceanalysis)Co-3SS316

Nocrackformationinthecoating四閥門密封面應(yīng)用研究(Application)LasercladdingofballvalvesealingsurfaceLasercladdingofbutterflyvalvesealingsurfaceMacroscopicfeatureanddyedetection編號(hào)激光光斑直徑mm線速度mm/min送粉量g/min搭接率比能kJ/cm26#43601350%6.66激光熔覆工藝參數(shù)(Lasercladdingprocessparameters:)粉末成分(Powderchemicalcomposition:)Stellite3:Stellite21CCrWMoFeNiSiMnB7:31.7629.458.751.654.403.201.701.700.70實(shí)體閥門熔覆(Lasercladdingofvalvesealingsurface)四閥門密封面應(yīng)用研究(Application)SwitchfrequencySS316Co-33000NoleakageoccurrenceNoleakageoccurrence5000LeakageoccurrenceNoleakageoccurrence10000-Noleakageoccurrence15000-Noleakageoccurrence25000-Noleakageoccurrence50000-Noleakageoccurrence閥門擦傷試驗(yàn)機(jī)Valveswitchtester在WI-0916標(biāo)準(zhǔn)測(cè)試下，蝶閥在50000次開(kāi)關(guān)閉測(cè)試中無(wú)泄露發(fā)生，符合企業(yè)生產(chǎn)測(cè)試標(biāo)準(zhǔn)。Noleakageoccursinthesealingsurfaceoflasercladdingonbutterflyvalveunderspecifiedduration.實(shí)體閥門擦傷試驗(yàn)(Valveswitchtest)Stellite3與Stellite21的最優(yōu)質(zhì)量配比為7:3；物相主要由fcc-Co、Co3Mo、(Co,W)3C、Cr7C3、Cr23C6

組成；含碳量的降低與強(qiáng)韌相金屬間化合物Co3Mo的出現(xiàn)使熔覆層在保持較高硬度的情況下有效阻止了裂紋的形成。Theoptimalchemicalcompositionwith70wt%Stellite3plus30wt%Stellite21exhibitsamicrostructurecontainingfcc-Co,Co3Mo,(Co,W)3C,Cr7C3andCr23C6.Thesephasesprovidehighhardnessbutnocrackformationinthecoating.新型Co基合金熔覆層的常溫磨損機(jī)理主要為氧化物的黏著與外表持續(xù)受到?jīng)_擊應(yīng)力形成的碳化物與金屬間化合物的脆性剝落；擦傷機(jī)理主要為塑性變形引起的裂紋的擴(kuò)展與塑性去除。Thewearmechanismsofthenewcoatingincludesadhesionofoxidesandbrittlespallationofcarbidesandintermetalliccompounds.Theabrasiveweariscausedbytheplasticdeformationatthesub-layerandremovalofthesurfacelayer.實(shí)體閥門激光熔覆顯示閥門外表形貌良好，無(wú)裂紋產(chǎn)生；蝶閥在WI-0916標(biāo)準(zhǔn)下50000次開(kāi)關(guān)閉測(cè)試中無(wú)泄漏發(fā)生，滿足實(shí)際應(yīng)用的要求。Goodappearanceandnocrackformationinthecoatinglayeronthevalvesealingsurfaceinapplication.Noleakageoccursonthesealingsurfacewiththenewalloycoatingonbutterflyvalvesunderspecifieddurationof50000cycles.五結(jié)論與展望(Conclusionsandprospects)結(jié)論(Conclusions)展望(Prospects)實(shí)驗(yàn)室下一步方案制備出規(guī)格一致的新型Co基粉末顆粒，便于產(chǎn)業(yè)化。NovellasercladdingsingleStellitealloypowderwhichcanbeappliedonthesealingsurfaceofshouldbefabricatedwiththerequiredchemicalcomposition可以增加細(xì)化組織的Nb元素，生成高熔點(diǎn)的穩(wěn)定相NbC。得到組織更細(xì)密、均勻、耐磨性更好、硬度更高的熔覆層。Nbelementmaybea