greyironpresentation灰铁的冶金讲解课件

BasicMetallurgyGreyIron.

灰铁的冶金学基本理论27.07.2023Developingpeople-creatingvalue2Greyironistheoldest(i.e.hasexistedlongest)ofthecastironsandthuscastironisoftensynonymuswithgreycastiron.Unfortunatelymostpeopleknowgreyirontobebrittleandthusbelieveallcastironstobebrittle.灰铁是最古老的铸铁之一，灰铁通常也称之为灰口铸铁。不幸的事，大多数都知道灰铁是易脆的，因此人们认为所有的铸铁都是易脆的。Greyironiscalledgreybecauseofthecolourofitsfracturesurface.Thecarbonispresentasmoreorlesscontinuousflakesofgraphitewithinamatrixofnormallymostlypearlitebutitcanalsocontainsomeferrite.Greyironhasagoodfluidityandincombinationwiththeexpansionofthegraphiteduringsolidificationmakesitidealforcastingofshrinkagefreecomplexpartslikeengineblocks.灰铁之所以被称之为灰铁，是因为其断口成灰色。大多数碳在灰铁是以连续状的片状石墨存在于绝大多数为珠光体基体中，同时基体中也会存在少量的铁素体。灰铁具有很好的流动性结合在凝固过程中的石墨化膨胀使得灰铁是铸造无缩松的发动机缸体的理想材料。Theflakesingreyironareimportantforthemechanicalproperties.Thegraphiteflakesinducesstressintheironmatrixandpossiblecrackswillrapidlypropagatealongtheflakes.Thisisthecauseoftheverysmallplasticelongationbeforerupture.Thegraphiteflakesmakestheironeasytomachine,actingaslubricant.灰铁中的片状石墨对其机械性能有着十分重要的影响。片状石墨可以引导基体中的应力和裂纹沿着片状石墨快速传播。这导致了灰铁在失效时只具有很小的塑性。片状石墨在机加工时起到了润滑作用，使得灰铁很容易被加工。IntroductiontoGreyCastIron

灰口铸铁的介绍SomeexamplesofcastingsinGreyIron

一些灰铁的应用案例27.07.2023Developingpeople-creatingvalue3WhyGreyIron?为什么选择灰铁lowrawmaterialcosts原材料成本低lowproductioncosts生产成本低

highcastingyield成品率较高goodcastingqualities好的铸造质量lowgaspick-up吸气较少goodas-castproperties较好的毛胚件质量easymachinable易加工gooddampingquality较好的减震性能goodcorrosionresistance较好的防腐蚀性能easilyalloyed易合金化temperaturestability耐热性能27.07.2023Developingpeople-creatingvalue4GreyIron-FlakeGraphite

灰铁—片状石墨27.07.2023Developingpeople-creatingvalue5NormalCompositionRange:通常的成分范围：2.5-4.0%Carbon碳1.0-3.0%Silicon硅0.4-1.0%Manganese锰0.05-1.0%Phosphorous磷max0.2%Sulphur

硫Thecompositionhastobeselectedtosatisfy:成分选择需要满足以下要求：requiredgraphiteshapeanddistribution必要的石墨形态和分布carbide-freestructure金相结构中无碳化物requiredmatrix必要基体组织©ElkemMechanicalProperties机械性能TensileStrength: 100-450MPaElongation: <1%Themechanicalpropertiesandthemicrostructureofgreyirondependson:机械性能和金相结构取决于以下：Sectionsize壁厚ChemicalComposition化学成分CoolingRate冷去速率NucleationPotential形核潜力©ElkemSectionSize壁厚Microstructure金相结构Properties性能SectionSize壁厚+=fIncreasingSectionSize DecreasingCoolingRategraphitecoarsening石墨粗化increasinggrainsize晶粒尺寸增大pearlitecoarsening珠光体变粗糙©ElkemSectionSize壁厚Asthesectionsizeincreasesthestrengthofgreycastironsfalls.随着壁厚的增加灰铸铁的强度是在降低的。*TypicalMicrostructuresofCastMetals-IBF©ElkemFe-C–Phasediagram铁碳相图**ASMSpecialtyHandbookFe-C–Phasediagram铁碳相图27.07.2023Developingpeople-creatingvalue10Consistsofastableandametastablesystem由稳定和亚稳定系统组成Stable稳定物Metastable亚稳定物Carbonasgraphite碳以石墨形式存在Eutecticpoint:4.3wt%CTeutectic=1153°CTeutectoid=738°CCarbonasFe3C碳以渗碳体形式存在Eutecticpoint:4.26wt%CTeutectic=1147°CTeutectoid=723°CEffectofCarboninGreyIron

碳在灰铁中的作用27.07.2023Developingpeople-creatingvalue11reducesmeltingtemperature降低熔点improvescastability改善铸造性能improvesmachinability改善机加工性能improvesdampingcapacity提高减震性reducesneedforfeeding降低缩水increasesthermalconductivity提高热传导性能decreaseschillingtendency减少白口倾向reducesmechanicalstrength降低机械强度coarsergraphitestructure粗化石墨结构©ElkemSilicon硅improvesgraphitisation促进石墨化reduceschillformation减少白口的形成promotesferrite促进铁素体promotesstablesolidification促进稳定凝固increasingcontentleadstocoarserpearlite提高粗糙珠光体的含量

©ElkemPhosphorous磷foundinallgreyirons所有灰铁中都含有increasesfluidity提高流动性formslow-meltingphosphideingreyiron;steadite,Fe3P在灰铁中形成低熔点的磷化物

；稳定的化合物Fe3Ppromotesshrinkageporosityathighlevels含量较高时促进疏松的产生promotesmeltpenetrationintomouldatverylowlevels

较低的含量下可以促进铁水向铸型渗透wearresistanceincreaseswithincreasingP-content提高磷的含量可以提高耐磨性能CarbonEquivalent碳当量27.07.2023Developingpeople-creatingvalue14Carbonequivalentformula:碳当量的公式EffectofCarbonEquivalentinGreyIron

碳当量在灰铁中的作用27.07.2023Developingpeople-creatingvalue15Strengthofgreyironwill,ingeneral,decreasewithincreasingcarbonequivalent.Whileamountofgraphiteinthestructureincreases.通常灰铁的强度将会随着碳当量的提高而降低；同时金相结构中的石墨也会增多。©ElkemManganese锰tiesupSandO束缚硫和氧reduceschillformation减少白口的形成promotesaustenite促进奥氏体strongpearlitepromoter强烈的珠光体促进剂weakcarbidepromoter弱的碳化物促进剂TotieupS: %Mn=1.7[%S]+0.3Togivepearliticstructure: %Mn=3[%S]+0.35Manganese锰27.07.2023Developingpeople-creatingvalue17©ElkemSulphur硫foundinallgreyirons所有灰铁中都有pearlitepromoterformslow-meltingsulphideingreyiron,FeSbalancedoutbyMntoMnS,whichactsasnucleationpointspromotessmallereutecticcellshardnessincreasewithincreasingS-levelUTSvsSulphurContent

抗拉强度与硫含量的关系27.07.2023Developingpeople-creatingvalue19©ElkemSulphur硫wt%SHighchillingtendencyLargeGrainsD-graphite过冷度大，晶粒较大，D型石墨HighchillingtendencyFineGrainsD-graphite过冷度大，晶粒细小，D型石墨LowchillingtendencyMediumSizeGrainsA-graphite过冷度较小，晶粒尺寸适中，A型石墨EffectofManganeseandSulphur

锰和硫的作用27.07.2023Developingpeople-creatingvalue21EquilibriumreactionMnS:Mn+S↔MnS反应平衡式EquilibriumreactionFeS:Fe+S↔FeS反应平衡式Stoichiometricbalance:[%Mn]=1.7[%S]ToensureonlyMnS:[%Mn]=1.7[%S]+0.30%ToachievemaximumstrengthprecipitationofMnShastosuppressedtoaslowtemperatureaspossiblepriortoonsetofsolidification.为了获得最大的强度，

要确保MnS的在凝固后期较低的温度下析出TooearlyMnSprecipitation=40–80MPalowerstrengthMnS过早析出=抗拉强度有40–80MPa的降低

Manganese&SulphurasfunctionofCE

锰和硫与碳当量的关系27.07.2023Developingpeople-creatingvalue22©ElkemTypeofGraphiteFlakes

石墨片层的种类EInterdendriticSegregationPreferredorientatedDInterdendriticSegregationRandomorientatedBRosetteGroupingRandomorientatedAInoculatedIronsUniformdistributedRandomorientatedCSuperimposedFlakeSizeRandomorientatedUndercooling,TC.EC.E=4.26FlakeGraphiteStructures

片层石墨结构27.07.2023Developingpeople-creatingvalue24GreyIronSolidification

灰铁的凝固曲线27.07.2023Developingpeople-creatingvalue25FlakeGraphiteSize

石墨片大小27.07.2023Developingpeople-creatingvalue26Effectofdifferentelementsontensilestrength

一些合金元素的灰铁抗拉强度的影响27.07.2023Developingpeople-creatingvalue27ChillDepthinGreyIron

灰铁中白口深度27.07.2023Developingpeople-creatingvalue28Thefigureshowstherelativechillingpowerofdifferentelements图形展示的是不同元素的促进白口能力EffectofVanadium

钒的作用27.07.2023Developingpeople-creatingvalue29Promotesformationofeutecticironcarbidewhichcanberemovedbyheattreatment可以促进合金碳化物的形成，这类碳化物可以通过热处理消除。Inoculationcanhelpreduceformationofeutecticcarbides孕育作用有助于减少共晶碳化物的形成LowchillingtendencyinhighcarbonironsandincombinationwithCu高碳铸铁和合金铜的加入可以降低白口倾向Increasesnucleationingreyirongivingfinerandmoreuniformgraphitestructures提高灰铁的形核率，从而可以细化石墨结构提高石墨结构的一致性SegregateswithPgivinghardparticleswithgoodslidingwearresistance与磷一起偏析形成硬点，从而形成耐磨层Increasesstrengthespeciallyinhighcarbongreyiron提高灰铁的强度，尤其是高碳灰铁MoreeffectivethanCrandMo比铬和钼的效率更高Factorsaffectingmachinability

影响机加工的因素27.07.2023Developingpeople-creatingvalue30Carboncontent碳含量Eutecticcellcount共晶团数量VolumeofMnSparticlesMnS颗粒的数量Mnlevel锰的含量Snlevel锡的含量ControlofPropertiesinGreyIron

灰铁性能的控制27.07.2023Developingpeople-creatingvalue31Fractureandcracksareinitiatedbytheflakegraphite.断裂和裂纹是开始于石墨片。SizeandDistributionofthegraphiteinGreyIronarethusthemost

importanttooltocontrolthemechanicalproperties.灰铁金相中的石墨的大小和分布是控制其铸件机械性能最重要的因素。CalculatedUTS–developedbyBateset.al.

抗拉强度的计算—有贝茨等人发明27.07.2023Developingpeople-creatingvalue32UTS=FactorA*FactorBFactorA:101.1193*(%TC+%Si/4+%P/2)+4.3887/castbarradiusFactorB:1.00+0.1371Si–0.0021(Mn-1.7S)–0.3131S+0.3562Cr+0.0282Ni+0.1107Cu+0.6297Mo–5.2985Ti–0.2350SnThecoefficientsaredevelopedfromregressionanalysis.系数是由回归分析法来计算获得的References参考文献27.07.2023Developingpeople-creatingvalue33Nucleationofgraphiteincastironmeltsdependingonmanganese,sulphurandoxygen.–A.Sommerfeld,B.TonnInternationaljournalofCatsMetalsResearch2008vol21no1-4•Tin-alloyedGreyIronCylinderBlocks–A.J.Tache,R.M.CageAmericanSocietyofAutomotiveEngineers14.January1964•Eutecticcellandnodulecountincastirons–E.Fras,M.Gorny,W.Kapturkiewicz,H.Lopez