激光熔覆新型Co基合金組織及擦性能研究5

1、激光激光熔覆新型熔覆新型CoCo基合金組織及擦傷基合金組織及擦傷性能性能研究研究Study of Microstructure and Abrasion Resistance of Novel Co-Based Alloy Laser Cladding Coatings 答辯人：任方成答辯人：任方成 Candidate Candidate: : Ren Ren FangchengFangcheng 導(dǎo)導(dǎo) 師：姚建華教授師：姚建華教授 AdvisorAdvisor: : Prof. Yao Prof. Yao JianhuaJianhua 時時 間：間：2015.5.262015.5.26 激光

2、先進(jìn)制造研究院激光先進(jìn)制造研究院目 錄(contents)研究背景及意義(Background and significance)Co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)閥門密封面應(yīng)用研究(Application)結(jié)論與展望(Conclusions and prospects)一一 研究背景及意義研究背景及意義(Background and significance)煤制油化工閥門工況要求(Coal liquefaction process) 直接液化Directliquefaction間接液化Indirectliquef

3、action 430470 1730MPa 350 2-3MPa 由 H2S, NH3, H2, CO, O2, Cl-等腐蝕性物質(zhì)引起的腐蝕 (Corrosion) 流體介質(zhì)中大量硬質(zhì)顆粒 造成的磨損、(Wear, abrasion caused by massive hard particles from liquid phase)擦傷失效Failure 沖蝕，氣蝕(Erosion, cavitation)擦傷HVOF工藝表面堆焊工藝(Welding)ENP(化學(xué)鍍鎳磷合金)工藝優(yōu)點：效率高，得到高性能涂層(Advantages: High efficiency)缺點：涂層結(jié)合力弱，涂層薄

4、(Disadvantages: Low bonding strength)優(yōu)點：經(jīng)濟(jì)性好，技術(shù)門檻低(Advantages: High economic efficiency)缺點：稀釋率大，熱影響區(qū)大 (Disadvantages: Higher dilution rate)優(yōu)點：大批量生產(chǎn)，涂層性能穩(wěn)定均勻(Advantages: Uniform properties )缺點：涂層薄，結(jié)合力較弱(Disadvantages: Thin coating, low bonding strength) 相比以上工藝，激光熔覆技術(shù)具有涂層結(jié)合力強，涂層相比以上工藝，激光熔覆技術(shù)具有涂層結(jié)合力強，涂

5、層厚度可控，稀釋率小，熱影響區(qū)小。厚度可控，稀釋率小，熱影響區(qū)小。(Strong bonding, lower dilution rate, adjustable coatingthickness)激光熔覆工藝(laser cladding)存在問題：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: Cracking in the high hardness coatings)優(yōu)點優(yōu)點(Advantage)：一一 研究背景及意義研究背景及意義(Background and significance)一一 研究背景及意義研究背景及意義(Background a

6、nd significance)激光熔覆Co合金粉末沿用熱噴涂粉末，主要類型有：Thermal spray powder: 研發(fā)研發(fā)成本低，且大面積應(yīng)用時無裂紋、內(nèi)部缺陷出現(xiàn)的高性能激光熔覆用粉末是激光熔成本低，且大面積應(yīng)用時無裂紋、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。覆材料技術(shù)的難點。Challenge of laser cladding: No cracking in large-area coatings and low R & D costsCo基自熔性合金粉末(Co-based self fluxing alloy)金屬基/陶瓷復(fù)合粉末(Composite p

7、owder of ceramics and metal)Co基非自熔性合金粉末(Co-based non self fluxing alloy)粉末研發(fā)成本高；高性能涂層易出現(xiàn)開裂、表面或內(nèi)部缺陷問題。(High costs in R & D; Cracking found in coatings)成型能力、造渣能力及對熔池的保護(hù)差。(Poor weld pool protection)硬質(zhì)顆粒在潤濕性、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-homogenous mechanical properties caused by different coefficients o

8、f thermal expansion)一一 研究背景及意義研究背景及意義(Background and significance)課題的課題的意義和創(chuàng)新點意義和創(chuàng)新點(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)用時易裂的技術(shù)瓶頸。(Development of novel laser cladding Stellite alloy powder with 70wt% high-carbon Stellite alloy plus 30wt%

9、low carbon Stellite alloy to reduce cracking in the coating layer.)采用自動劃痕儀進(jìn)行單點劃痕模擬避免了傳統(tǒng)閥門擦傷試驗必須在進(jìn)行實體閥門開關(guān)閉測試的限制。對劃痕深度、加工硬化特性，切向力與劃痕形貌進(jìn)行了分析。(This novel coating has been applied on the sealing surface of ball valves and butterfly valves. The performance of the coating is investigated under work hardeni

10、ng test.)激光熔覆專用合金粉末的調(diào)配(Special powder preparation)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(Process parameter optimization)單道多道搭接試驗、制備試樣。進(jìn)行組織物相與性能的分析(Performance analysis)球閥、蝶閥實體熔覆與擦傷泄露測試。(Valve sealing surface laser cladding)本文的工作本文的工作內(nèi)容內(nèi)容(Work contents)二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)煤制油閥門密封面工況特

11、殊要求(Coal liquefaction process)需具有抗沖蝕、抗氣蝕與抗擦傷的能力(Erosion, cavitation and abrasion reisitance)抗H+、 H2S 、Cl-腐蝕的能力(Corrosion caused by H+, H2S, Cl-)粉末的調(diào)配粉末的調(diào)配(Powder preparation)numbermaterialsability1Co-Cr-W alloyexcellent217-4PH or 17-7PHgood3SA 182-F316 or SA 182-F316Lgood4Cr-Mo steelcommon5Cast iron

12、common(Strong carbide-forming elements)結(jié)合力強弱：FeMnCrMoWMo + SprecipitationAlloy CrWMoCFeNiSiMnHRCapplicationStellite 330.512.5 -2.453.52260Valve seat etc.Stellite 4301410.57332141Hot embossing mould etc.Stellite 628.54.51.51532240Engine valve etc.Stellite 12308.3 -1.431.50.72.542Sawtooth etc.Stellite

13、 2127 -5.50.2532.751128Turbine blade etc.Stellite 31227.5 -0.51.5100.50.531Turbine blade etc.Stellite 8033.519 -2.0- - - - 52Bearing sleeve etc.Alloy CrWMoCFeNiSiMnHRCapplicationStellite 330.512.5 -2.453.52260Valve seat etc.Stellite 2127 -5.50.2532.751128Turbine blade etc.合金的選擇(Selection of alloy)：1

14、、Co基合金基合金 (Co-based alloy )2、合金中需含有足夠的強化相（碳化物等）阻止擦傷合金中需含有足夠的強化相（碳化物等）阻止擦傷 (Enough strengthening phase to prevent abrasion)Stellite 3Co-Cr-WHigher carbon content, higher hardnessWear and abrasion resistanceStellite 21Co-Cr-MoLower carbon content, lower hardness, better work hardening Relatively low w

15、ear resistanceNew alloyCo-Cr-W-MoGood Macroscopic feature Wear and abrasion resistanceHigh hardness, work hardening二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)Crack occurs in laser cladding coatings3、合金中需要強碳化物形成元素合金中需要強碳化物形成元素W、Cr去防止氫腐蝕的發(fā)生；去防止氫腐蝕的發(fā)生；Mo元素可以與元素可以與S形成形成彌散彌散 析出析出物，削弱物，削弱H2S腐蝕腐蝕 （The ne

16、w alloy needs containing W、Mo and Cr element）No crack formation in laser cladding coatings序號序號Stellite 3Co-1Co-2Co-3層高層高層高層高1 #4454755125362 #4824685235323 #4734955185504 #7127397257935 #7487747918206 #7978108339207 #1047116312201254編號編號功率功率kW掃描速度掃描速度mm / min送粉量送粉量g / min比能比能kJ / cm21 #0.61801052 #0

17、.8180105.833 #1180106.664 #1.23601355 #1.4360135.836 #1.6360136.667 #1.8540165Stellite 3: Stellite 21=7:3(wt%) (Co-3)激光工藝優(yōu)化激光工藝優(yōu)化(Laser process optimization)Stellite 3Stellite 3: Stellite 21=9:1(wt%) (Co-1)Stellite 3: Stellite 21=8:2(wt%) (Co-2)Stellite 3Co-3Co-2Co-17#1#(Coating layer height)單層高度測試

18、(m)(Hardness test)硬度測試二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)Stellite 3Co-1Co-3Co-23#熔覆層6#熔覆層6#熔覆層3#熔覆層(Dilution rate)稀釋率：稀釋率：55.1%(Dilution rate)稀釋率：稀釋率：32%(Dilution rate)稀釋率：稀釋率：33%(Dilution rate)稀釋率：稀釋率：42%(Layer height)高度：高度：473m(Layer height)高度：高度：495m(Layer height)高度：高度：833m(Layer height

19、)高度：高度：920mStellite 21的逐漸增多(Addition of Stellite 21)新合金中B、Si含量減少，熔點升高(Decrease of B, Si content)熔池流動性變差、黏度增大，熔融狀態(tài)不易外流 (Liquidity variation)稀釋率更小(Lower dilution rate)Stellite 3Co-1Co-2Co-3優(yōu)化的參數(shù):(Optimal parameters)：Co-3合金 (Stellite 3: Stellite 21= 7: 3) (wt%) 6# (功率: 1600W, 送粉量: 13g/min, 掃描速度: 6mm/s)

20、二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)層高更高(Thicker layer )激光工藝激光工藝優(yōu)化優(yōu)化(Laser process optimization)較大面積的搭接試驗(large overlaping test )涂層顯微組織分析涂層顯微組織分析（Microstructure analysis）Stellite 3Co-3Co-2Co-1Stellite 21的加入(Addition of Stellite 21)新合金組織粗大(Coarse grains)新合金中W含量減少, Mo含量增加(W content decreases,

21、 Mo content increases)W元素細(xì)化晶粒的能力強于Mo元素(W element is better than Mo element in the ability of grain refinement )Co-3合金面掃秒分析(Map analysis of Co-3)AreaCCrWMoFeCo15.2319.6120.975.806.35Bal.24.9625.3615.744.287.39Bal.39.2535.999.192.596.41Bal.123二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)物物相分析相分析(Phase

22、 analysis)Stellite 3Stellite 21Co-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較高的較高的W、Mo含量更容易形成含量更容易形成(Co,W)6C, Co7Mo6(Higher W and Mo content is easier to form (Co,W)6C, Co7Mo6)相反

23、的，較低的相反的，較低的W、Mo含量更容易含量更容易形成形成(Co, W)3C, Co3Mo(Lower W and Mo content easily forms (Co,W)3C and Co3Mo)二二 Co基合金熔覆工藝基合金熔覆工藝與與組織研究組織研究(Microstructure)三三 Co基合金熔覆層性能分析基合金熔覆層性能分析(Performance)摩擦磨損性能分析摩擦磨損性能分析(Wear performance investigation)Stellite 3Stellite 21Co-3三種合金磨損體積(wear loss)摩擦系數(shù)曲線(Friction coeffic

24、ient curves)Stellite 3Co-3Stellite 21三三 Co基合金熔覆層性能分析基合金熔覆層性能分析(Performance)摩擦磨損性能分析摩擦磨損性能分析(Wear surface analysis)添加了添加了Stellite 21的的Co-3合金中，合金中，Co3Mo阻礙磨損的作用與阻礙磨損的作用與(Co,W)3C相似相似Co3Mo phase has similar effect on wear resistance to (Co,W)3C phase. 擦傷性能分擦傷性能分析析(Abrasion performance analysis)最大載荷下的劃痕深度

25、Indentation depth at maximum load:SS316: 17.1m Co-3: 8.1mSS316Co-3Hardness unchangedHardness increased to 835HV0.2Scratch grooveSectionSS316Co-3Hardness unchangedHardness increased to 918HV0.2Plastic deformationfcc-Cohcp-CoHardness劃傷影響區(qū)約為劃傷影響區(qū)約為120m，新型，新型Co基合金存在加工硬化基合金存在加工硬化現(xiàn)象現(xiàn)象(Work hardening pheno

26、menon can be found on new alloy coating surface)加工硬化性能測試（Work hardening）三三 Co基合金熔覆層性能分析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Indentation depth variations with load increase for SS316 and new alloy Stable stageSS316Co-3擦傷性能分析擦傷性能分析(Abrasion performance analysis)三三 Co基合金熔覆層性能分析基合金熔覆層性能分析(Perfo

27、rmance)SS316Co-3擦傷性能分析擦傷性能分析(Abrasion performance analysis)small change stageSS316Co-3三三 Co基合金熔覆層性能分析基合金熔覆層性能分析(Performance)SS316Co-3large change stageSS316Co-345F90三三 Co基合金熔覆層性能分析基合金熔覆層性能分析(Performance)擦傷性能分析擦傷性能分析(Abrasion performance analysis)Co-3SS316 No crack formation in the coating四四 閥門密封面應(yīng)用研

28、究閥門密封面應(yīng)用研究(Application)Laser cladding of ball valve sealing surfaceLaser cladding of butterfly valve sealing surfaceMacroscopic feature and dye detection編號編號激光光斑直徑激光光斑直徑mm線速度線速度mm / min送粉量送粉量g / min搭接率搭接率比能比能kJ / cm26 #43601350 %6.66激光熔覆工藝參數(shù)(Laser cladding process parameters:)粉末成分(Powder chemical co

29、mposition:)Stellite 3 : Stellite 21 CCrWMoFeNiSiMnB7 : 31.7629.458.751.654.403.201.701.700.70實體實體閥門閥門熔覆熔覆(Laser cladding of valve sealing surface)四四 閥門密封面應(yīng)用研究閥門密封面應(yīng)用研究(Application)Switch frequencySS316Co-33000No leakage occurrenceNo leakage occurrence5000Leakage occurrenceNo leakage occurrence10000-

30、No leakage occurrence15000-No leakage occurrence25000-No leakage occurrence50000-No leakage occurrence閥門擦傷試驗機Valve switch tester在WI-0916 標(biāo)準(zhǔn)測試下，蝶閥在50000次開關(guān)閉測試中無泄露發(fā)生，符合企業(yè)生產(chǎn)測試標(biāo)準(zhǔn)。No leakage occurs in the sealing surface of laser cladding on butterfly valve under specified duration.實體實體閥門閥門擦傷試驗擦傷試驗(Valve

31、 switch test)pStellite 3 與 Stellite 21 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。pThe optimal chemical composition with 70wt% Stellite 3 plus 30wt% Stellite 21 exhibits a microstructure containing fcc-Co, Co3Mo, (Co,W)3C, Cr7C3 and Cr

32、23C6. These phases provide high hardness but no crack formation in the coating. p新型 Co 基合金熔覆層的常溫磨損機理主要為氧化物的黏著與表面持續(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；擦傷機理主要為塑性變形引起的裂紋的擴展與塑性去除。p The wear mechanisms of the new coating includes adhesion of oxides and brittle spallation of carbides and intermetallic compounds. The

33、 abrasive wear is caused by the plastic deformation at the sub-layer and removal of the surface layer. p實體閥門激光熔覆顯示閥門表面形貌良好，無裂紋產(chǎn)生；蝶閥在 WI-0916 標(biāo)準(zhǔn)下50000次開關(guān)閉測試中無泄漏發(fā)生，滿足實際應(yīng)用的要求。p Good appearance and no crack formation in the coating layer on the valve sealing surface in application. No leakage occurs on

34、the sealing surface with the new alloy coating on butterfly valves under specified duration of 50000 cycles. 五五 結(jié)論與展望結(jié)論與展望(Conclusions and prospects)結(jié)論結(jié)論(Conclusions)展望展望(Prospects)p實驗室下一步計劃制備出規(guī)格一致的新型 Co 基粉末顆粒，便于產(chǎn)業(yè)化。pNovel laser cladding single Stellite alloy powder which can be applied on the sealing surface of should be fabricated with the required chemical compositionp可以增加細(xì)化組織的Nb 元素，生成高熔點的穩(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。pNb element may be added to this new powder to refine micro