Grinding Technology-chapter2

GrindingWheels:CompositionandPropertiesProfessorLiZhengxinSchoolofMaterialsScienceandEngineeringHenanUniversityofTechnologyBilingualCourseNovember23,2010GrindingTechnology2.1IntroductionGrindingwheelsorabrasivesegments:bondedabrasives,consistofabrasivegrains/grits,hard,dothecutting;binder,bondingmatrix,weaker;porosity:grindingheatdissipation,chipoutfiller:lubricating,etc.grinding-aidmaterials:chemicalaction,etcPropertiesandperformancedependingontypeofabrasivegrainmaterials,sizeofthegrit,thebondmaterialpropertiesofabrasiveandbond,andtheporosity.2.1Introduction磨具的种类：按磨料种类划分磨具普通磨料磨具氧化物磨料磨具碳化物磨料磨具陶瓷刚玉磨具棕刚玉磨具白刚玉磨具单晶刚玉磨具微晶刚玉磨具铬刚玉磨具锆刚玉磨具黑碳化硅磨具绿碳化硅磨具立方碳化硅磨具铈碳化硅磨具超硬磨料磨具碳化物磨料磨具氮化物磨料磨具金刚石磨具立方氮化硼磨具2.1IntroductionVarioustypesofabrasives:classifiedbygritskindAbrasivesConventionalabrasivesOxideabrasivesCarbideabrasivesCeramiccorundumabrasivesBrowncorundumabrasivesWhitecorundumabrasivesMonocrystalcorundumabrasivesMicrocrystalcorundumabrasivesChromecorundumabrasivesZirconiacorundumabrasivesBlacksiliconcarbideabrasivesGreensiliconcarbideabrasivesCubicsiliconcarbideabrasivesCeriumsiliconcarbideabrasivesSuper-abrasivesCarbideabrasivesNitrideabrasivesDiamondabrasivesCubicboronnitrideabrasivesZirconiacorundumabrasivesalsonamedpinkfusedalumina2.1Introduction按结合剂分类无机结合剂磨具有机结合剂磨具金属结合剂磨具磨具陶瓷结合剂磨具菱苦土结合剂磨具硅酸钠结合剂磨具树脂结合剂磨具橡胶结合剂磨具固结磨具磨具研磨膏砂轮砂瓦磨头磨石抛磨块涂附磨具砂布砂纸砂盘砂带页轮硬膏软膏按形状分类2.1IntroductionClassifiedbybondingagentInorganicbondabrasivesOrganicbondabrasivesMetallicbondabrasivesAbrasi-vesVitrifiedabrasivesOxychlroideabrasivesSodiumsilicateabrasivesResinbondabrasivesRubberbondabrasivesBondedabrasivesAbrasivesLappingpasteGrindingwheelGrindingsegmentMountedwheelGrindingsticksTumblingchipCoatedabrasivesAbrasiveclothAbrasivepaperAbrasivesdiscAbrasivebeltFlapwheelHardpasteSoftpasteClassifiedbyshape2.1Introduction棕刚玉ABrownAlumina白刚玉WAWhiteAlumina绿碳化硅GCGreenCarborundum黑碳化硅CBlackCarborundum人造金刚石SynthesisDiamond立方氮化硼CBNCubicBoronNitride2.1Introduction固结磨具BABondAbrasives涂附磨具CACoatedAbrasives超硬磨具SASuperAbrasives2.2Grindingwheelspecification:conventionalabrasivesThewheelspecificationdefinesthefollowingparameters,2.2Grindingwheelspecification:conventionalabrasivesThestandardconventionalwheelmarkingsystemusedinNorthAmerica2.2Grindingwheelspecification:conventionalabrasivesGrain:BrowncorundumWhitecorundumMonocrystalcorundumMicrocrystalcorundumChromecorundumZirconiacorundumCeramiccorundumBlacksiliconGreensiliconcarbideCubicsiliconcarbideCeriumsilicon2.2Grindingwheelspecification:conventionalabrasivesGrainsize:Gritnumber:relatedtothemeshnumberLargernumber,smallergrainsizeSievingmethod:usedforcoarsergrainthan240Sedimentation:usedforfinergritsthan240Astandardgritnumberisdefinedintermsofgrainsizescorrespondingtofivesuchsieves.e.g.Gritnumber46involvesgrainscaughtonsievesnumber30,40,45,50,and60usingastandardsamplesizeandsieve-shakingprocedure.SieveRetentionPassingsize(micrometer)#300100=595#4030=70(595-420)30%#45=4060(420-354)=40%#45and#50=6535(420-297)=65%#6097=3%(595-250)97%e.g:#46330μm415μm320μm2.2Grindingwheelspecification:conventionalabrasives2.2Grindingwheelspecification:conventionalabrasivesHardness/Grade:Indicatesthewheelstrengthandthedegreetowhichabrasivegrainsaretightlyheldbythebinder.h0h1P0P1P=P0+P1洛氏法测定硬度φ6PVφ12大越式硬度计取信号点取信号点敲击点敲击点45°45°喷砂法测定硬度音频法硬度检测2.2Grindingwheelspecification:conventionalabrasivesHardness/Grade:硬度指磨粒在外力作用下从其表面脱落的难易程度。砂轮硬度的选用原则是：工件材料越硬，应选用越软的砂轮。这是因为硬材料使磨粒磨损，需用较软的砂轮以使磨钝的磨粒及时脱落。工件材料越软，砂轮的硬度应越硬，以使磨粒脱落慢些，发挥其磨削作用。但在磨削有色金属、橡胶、树脂等软材料时，要用较软的砂轮，以便使堵塞处的磨粒较易脱落，露出锋锐的新磨粒。半精磨与粗磨相比，需用较软的砂轮；但精磨和成形磨削时，为了较长时间保持砂轮轮廓，需用较硬的砂轮。大级超软软中软中中硬硬超硬名称超软1超软2超软3软1软2软3中软1中软2中1中2中硬1中硬2中硬3硬1硬2超硬代号DEFGHJKLMNPQRSTY2.2Grindingwheelspecification:conventionalabrasivesStructure:Packingdensity有色金属及塑料、橡胶等非金属以及热敏合金粗磨及磨削韧性大、硬度低的工件，适合磨削薄壁、细长工件，或砂轮与工件接触面大以及平面磨削等外圆、内圆、无心磨及工具磨，淬硬工件及刀具刃磨等重负载、成形、精密磨削，加工脆硬材料适用范围大气孔疏松中等紧密疏密程度343638404244464850525456586062磨粒率/(%)14131211109876543210组织号2.2Grindingwheelspecification:conventionalabrasivesBond:2.3Grindingwheelspecification:superabrasivesStandardMarkingSystemforCubicBoronNitrideandDiamondBondedAbrasives2.3Grindingwheelspecification:superabrasives2.3Grindingwheelspecification:superabrasivesGritsize:2.3Grindingwheelspecification:superabrasivesGritsize:2.3Grindingwheelspecification:superabrasivesGrade:2.3Grindingwheelspecification:superabrasivesConcentration:2.3Grindingwheelspecification:superabrasivesConcentration:2.4ConventionalabrasivesmaterialsAbrasivematerials:2.4ConventionalabrasivesmaterialsAbrasivematerials:2.4SuperabrasivesmaterialsAbrasivematerials:DiamondandCBN（SeeWikipediapages)2.5SuperabrasivesmaterialsAbrasivematerials:DiamondandCBN（SeeWikipediapages)2.6BondmaterialsBondmaterials:2.7Vitrifiedwheelcompositionandphasediagram2.8GrindingwheeltestingHardnesstestingStrengthtestingHomework1.Describethegrindingwheelphasediagramfunctioninchief.2.Briefintroducingthegradetestingmethodsgrindingwheel.