激光熔覆新型Co基合金组织及擦性能研究5

1、激光激光熔覆新型熔覆新型CoCo基合金组织及擦伤基合金组织及擦伤性能性能研究研究Study of Microstructure and Abrasion Resistance of Novel Co-Based Alloy Laser Cladding Coatings 答辩人：任方成答辩人：任方成 Candidate Candidate: : Ren Ren FangchengFangcheng 导导 师：姚建华教授师：姚建华教授 AdvisorAdvisor: : Prof. Yao Prof. Yao JianhuaJianhua 时时 间：间：2015.5.262015.5.26 激光

2、先进制造研究院激光先进制造研究院目 录(contents)研究背景及意义(Background and significance)Co基合金熔覆工艺与组织研究(Microstructure)Co基合金熔覆层的性能分析(Performance)阀门密封面应用研究(Application)结论与展望(Conclusions and prospects)一一 研究背景及意义研究背景及意义(Background and significance)煤制油化工阀门工况要求(Coal liquefaction process) 直接液化Directliquefaction间接液化Indirectliquef

3、action 430470 1730MPa 350 2-3MPa 由 H2S, NH3, H2, CO, O2, Cl-等腐蚀性物质引起的腐蚀 (Corrosion) 流体介质中大量硬质颗粒 造成的磨损、(Wear, abrasion caused by massive hard particles from liquid phase)擦伤失效Failure 冲蚀，气蚀(Erosion, cavitation)擦伤HVOF工艺表面堆焊工艺(Welding)ENP(化学镀镍磷合金)工艺优点：效率高，得到高性能涂层(Advantages: High efficiency)缺点：涂层结合力弱，涂层薄

4、(Disadvantages: Low bonding strength)优点：经济性好，技术门槛低(Advantages: High economic efficiency)缺点：稀释率大，热影响区大 (Disadvantages: Higher dilution rate)优点：大批量生产，涂层性能稳定均匀(Advantages: Uniform properties )缺点：涂层薄，结合力较弱(Disadvantages: Thin coating, low bonding strength) 相比以上工艺，激光熔覆技术具有涂层结合力强，涂层相比以上工艺，激光熔覆技术具有涂层结合力强，涂

5、层厚度可控，稀释率小，热影响区小。厚度可控，稀释率小，热影响区小。(Strong bonding, lower dilution rate, adjustable coatingthickness)激光熔覆工艺(laser cladding)存在问题：高硬度、耐磨损、耐腐蚀合金粉末大面积应用易出现裂纹，孔洞等缺陷。(Problems: Cracking in the high hardness coatings)优点优点(Advantage)：一一 研究背景及意义研究背景及意义(Background and significance)一一 研究背景及意义研究背景及意义(Background a

6、nd significance)激光熔覆Co合金粉末沿用热喷涂粉末，主要类型有：Thermal spray powder: 研发研发成本低，且大面积应用时无裂纹、内部缺陷出现的高性能激光熔覆用粉末是激光熔成本低，且大面积应用时无裂纹、内部缺陷出现的高性能激光熔覆用粉末是激光熔覆材料技术的难点。覆材料技术的难点。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)金属基/陶瓷复合粉末(Composite p

7、owder of ceramics and metal)Co基非自熔性合金粉末(Co-based non self fluxing alloy)粉末研发成本高；高性能涂层易出现开裂、表面或内部缺陷问题。(High costs in R & D; Cracking found in coatings)成型能力、造渣能力及对熔池的保护差。(Poor weld pool protection)硬质颗粒在润湿性、稳定性及热膨胀系数方面的不同导致力学性能不均匀。(Non-homogenous mechanical properties caused by different coefficients o

8、f thermal expansion)一一 研究背景及意义研究背景及意义(Background and significance)课题的课题的意义和创新点意义和创新点(Significance and innovation)获得了熔覆层在碳含量降低与 Mo 元素增加后的组织与耐磨性的变化规律；制备新型 Co 基高性能激光熔覆层克服了高硬度 Co 基合金大面积应用时易裂的技术瓶颈。(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.)采用自动划痕仪进行单点划痕模拟避免了传统阀门擦伤试验必须在进行实体阀门开关闭测试的限制。对划痕深度、加工硬化特性，切向力与划痕形貌进行了分析。(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.)激光熔覆专用合金粉末的调配(Special powder preparation)优化工艺参数：1 不同粉末配比2 工艺与涂层硬度3 金相组织(Process parameter optimization)单道多道搭接试验、制备试样。进行组织物相与性能的分析(Performance analysis)球阀、蝶阀实体熔覆与擦伤泄露测试。(Valve sealing surface laser cladding)本文的工作本文的工作内容内容(Work contents)二二 Co基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(Microstructure)煤制油阀门密封面工况特

11、殊要求(Coal liquefaction process)需具有抗冲蚀、抗气蚀与抗擦伤的能力(Erosion, cavitation and abrasion reisitance)抗H+、 H2S 、Cl-腐蚀的能力(Corrosion caused by H+, H2S, Cl-)粉末的调配粉末的调配(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)结合力强弱：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.合金的选择(Selection of alloy)：1

14、、Co基合金基合金 (Co-based alloy )2、合金中需含有足够的强化相（碳化物等）阻止擦伤合金中需含有足够的强化相（碳化物等）阻止擦伤 (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基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(Microstructure)Crack occurs in laser cladding coatings3、合金中需要强碳化物形成元素合金中需要强碳化物形成元素W、Cr去防止氢腐蚀的发生；去防止氢腐蚀的发生；Mo元素可以与元素可以与S形成形成弥散弥散 析出析出物，削弱物，削弱H2S腐蚀腐蚀 （The ne

16、w alloy needs containing W、Mo and Cr element）No crack formation in laser cladding coatings序号序号Stellite 3Co-1Co-2Co-3层高层高层高层高1 #4454755125362 #4824685235323 #4734955185504 #7127397257935 #7487747918206 #7978108339207 #1047116312201254编号编号功率功率kW扫描速度扫描速度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)激光工艺优化激光工艺优化(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)单层高度测试

18、(m)(Hardness test)硬度测试二二 Co基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(Microstructure)Stellite 3Co-1Co-3Co-23#熔覆层6#熔覆层6#熔覆层3#熔覆层(Dilution rate)稀释率：稀释率：55.1%(Dilution rate)稀释率：稀释率：32%(Dilution rate)稀释率：稀释率：33%(Dilution rate)稀释率：稀释率：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的逐渐增多(Addition of Stellite 21)新合金中B、Si含量减少，熔点升高(Decrease of B, Si content)熔池流动性变差、黏度增大，熔融状态不易外流 (Liquidity variation)稀释率更小(Lower dilution rate)Stellite 3Co-1Co-2Co-3优化的参数:(Optimal parameters)：Co-3合金 (Stellite 3: Stellite 21= 7: 3) (wt%) 6# (功率: 1600W, 送粉量: 13g/min, 扫描速度: 6mm/s)

20、二二 Co基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(Microstructure)层高更高(Thicker layer )激光工艺激光工艺优化优化(Laser process optimization)较大面积的搭接试验(large overlaping test )涂层显微组织分析涂层显微组织分析（Microstructure analysis）Stellite 3Co-3Co-2Co-1Stellite 21的加入(Addition of Stellite 21)新合金组织粗大(Coarse grains)新合金中W含量减少, Mo含量增加(W content decreases,

21、 Mo content increases)W元素细化晶粒的能力强于Mo元素(W element is better than Mo element in the ability of grain refinement )Co-3合金面扫秒分析(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基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(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较高的较高的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，较低的相反的，较低的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基合金熔覆工艺基合金熔覆工艺与与组织研究组织研究(Microstructure)三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Performance)摩擦磨损性能分析摩擦磨损性能分析(Wear performance investigation)Stellite 3Stellite 21Co-3三种合金磨损体积(wear loss)摩擦系数曲线(Friction coeffic

24、ient curves)Stellite 3Co-3Stellite 21三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Performance)摩擦磨损性能分析摩擦磨损性能分析(Wear surface analysis)添加了添加了Stellite 21的的Co-3合金中，合金中，Co3Mo阻碍磨损的作用与阻碍磨损的作用与(Co,W)3C相似相似Co3Mo phase has similar effect on wear resistance to (Co,W)3C phase. 擦伤性能分擦伤性能分析析(Abrasion performance analysis)最大载荷下的划痕深度

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划伤影响区约为划伤影响区约为120m，新型，新型Co基合金存在加工硬化基合金存在加工硬化现象现象(Work hardening pheno

26、menon can be found on new alloy coating surface)加工硬化性能测试（Work hardening）三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Performance)SS316与Co-3合金的划痕深度随载荷的变化Indentation depth variations with load increase for SS316 and new alloy Stable stageSS316Co-3擦伤性能分析擦伤性能分析(Abrasion performance analysis)三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Perfo

27、rmance)SS316Co-3擦伤性能分析擦伤性能分析(Abrasion performance analysis)small change stageSS316Co-3三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Performance)SS316Co-3large change stageSS316Co-345F90三三 Co基合金熔覆层性能分析基合金熔覆层性能分析(Performance)擦伤性能分析擦伤性能分析(Abrasion performance analysis)Co-3SS316 No crack formation in the coating四四 阀门密封面应用研

28、究阀门密封面应用研究(Application)Laser cladding of ball valve sealing surfaceLaser cladding of butterfly valve sealing surfaceMacroscopic feature and dye detection编号编号激光光斑直径激光光斑直径mm线速度线速度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激光熔覆工艺参数(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实体实体阀门阀门熔覆熔覆(Laser cladding of valve sealing surface)四四 阀门密封面应用研究阀门密封面应用研究(Application)Switch frequencySS316Co-33000No leakage occurrenceNo leakage occurrence5000Leakage occurrenceNo leakage occurrence10000-

30、No leakage occurrence15000-No leakage occurrence25000-No leakage occurrence50000-No leakage occurrence阀门擦伤试验机Valve switch tester在WI-0916 标准测试下，蝶阀在50000次开关闭测试中无泄露发生，符合企业生产测试标准。No leakage occurs in the sealing surface of laser cladding on butterfly valve under specified duration.实体实体阀门阀门擦伤试验擦伤试验(Valve

31、 switch test)pStellite 3 与 Stellite 21 的最优质量配比为7:3；物相主要由 fcc-Co、Co3Mo、(Co,W)3C、Cr7C3、Cr23C6 组成；含碳量的降低与强韧相金属间化合物 Co3Mo 的出现使熔覆层在保持较高硬度的情况下有效阻止了裂纹的形成。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 基合金熔覆层的常温磨损机理主要为氧化物的黏着与表面持续受到冲击应力形成的碳化物与金属间化合物的脆性剥落；擦伤机理主要为塑性变形引起的裂纹的扩展与塑性去除。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实体阀门激光熔覆显示阀门表面形貌良好，无裂纹产生；蝶阀在 WI-0916 标准下50000次开关闭测试中无泄漏发生，满足实际应用的要求。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 结论与展望结论与展望(Conclusions and prospects)结论结论(Conclusions)展望展望(Prospects)p实验室下一步计划制备出规格一致的新型 Co 基粉末颗粒，便于产业化。pNovel laser cladding single Stellite alloy powder which can be applied on the sealing surface of should be fabricated with the required chemical compositionp可以增加细化组织的Nb 元素，生成高熔点的稳定相 NbC。得到组织更细密、均匀、耐磨性更好、硬度更高的熔覆层。pNb element may be added to this new powder to refine micro