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机械类相关英语文章精选
机械类相关英语文章精选
WhatisHydraulic?
Apletehydraulicsystemconsistsoffiveparts,namely,powerponents,theimplementationofponents,controlponents,nopartsandhydraulicoil.Theroleofdynamicponentsoftheoriginalmotivefluidintomechanicalenergytothepressurethatthehydraulicsystemofpumps,itistopowertheentirehydraulicsystem.Thestructureoftheformofhydraulicpumpgearsaregenerallypump,vanepumpandpistonpump.Implementationofponents（suchashydrauliccylindersandhydraulicmotors）whichisthepressureoftheliquidcanbeconvertedtomechanicalenergytodrivetheloadforastraightlinereciprocatingmovementorrotationalmovement.Controlponents（thatis,thevarioushydraulicvalves）inthehydraulicsystemtocontrolandregulatethepressureofliquid,flowrateanddirection.Aordingtothedifferentcontrolfunctions,hydraulicvalvescanbedividedintothevillageofforcecontrolvalve,flowcontrolvalvesanddirectionalcontrolvalve.Pressurecontrolvalvesaredividedintobenefitsflowvalve（safetyvalve）,pressurereliefvalve,sequencevalve,pressurerelays,etc.;flowcontrolvalvesincludingthrottle,adjustingthevalves,flowdiversionvalvesets,etc.;directionalcontrolvalveincludesaone-wayvalve,one-wayfluidcontrolvalve,shuttlevalve,valveandsoon.Underthecontrolofdifferentways,canbedividedintothehydraulicvalvecontrolswitchvalve,controlvalveandsetthevalueoftheratiocontrolvalve.Auxiliaryponents,includingfueltanks,oilfilters,tubingandpipejoints,seals,pressuregauge,oillevel,suchasoildollars.Hydraulicoilinthehydraulicsystemistheworkoftheenergytransfermedium,thereareavarietyofmineraloil,emulsionoilhydraulicmoldingHopcategories.
Hydraulicprinciple
Itconsistsoftwocylindersofdifferentsizesandpositionoffluidinthefluidfullofwateroroil.Wateriscalled"hydraulicpress";thesaidoil-filled"hydraulicmachine."Eachofthetwoliquidaslidingpiston,iftheincreaseinthesmallpistononthepressureofacertainvalue,aordingtoPascal'slaw,smallpistontothepressureofthepressurethroughtheliquidpassedtothelargepiston,pistontopwillgoalongwaytogo.Basedcross-sectionalareaofthesmallpistonisS1,plusasmallpistoninthedownwardpressureontheF1.Thus,asmallpistonontheliquidpressuretoP=F1/SI,Canbethesamesizeinalldirectionstothetransmissionofliquid."BythelargepistonisalsoequivalenttotheinevitablepressureP.Ifthelargepistonisthecross-sectionalareaS2,thepressurePonthepistonintheupwardpressuregeneratedF2=PxS2Cross-sectionalareaisasmallmultipleofthepistoncross-sectionalarea.Fromthetypeknowntoaddinasmallpistonofasmallerforce,thepistonwillbeingreatforce,forwhichthehydraulicmachineusedtosuppressplywood,oil,extractheavyobjects,suchasforgingsteel.
Historyofthedevelopmentofhydraulic
Andairpressuredrivehydraulicfluidasthetransmissionismadeaordingtothe17thcentury,Pascal'sprincipleofhydrostaticpressuretodrivethe
developmentofanemergingtechnology,theUnitedKingdomin1795Joseph（JosephBraman,1749-1814）,inLondonwaterasamediumtoformhydraulicpressusedinindustry,thebirthoftheworld'sfirsthydraulicpress.Mediaworkin1905willbereplacedbyoil-waterandfurtherimproved.
WorldWarI（1914-1918）aftertheextensiveapplicationofhydraulictransmission,especiallyafter1920,morerapiddevelopment.Hydraulicponentsinthelate19thcenturyabouttheearly20thcentury,20years,onlystartedtoentertheformalphaseofindustrialproduction.1925Vickers（F.Vikers）theinventionofthepressurebalancedvanepump,hydraulicponentsforthemodernindustrialorhydraulictransmissionofthegradualestablishmentofthefoundation.Theearly20thcenturyConstantine（G?
Constantimsco）fluctuationsoftheenergycarriedoutbypassingtheoreticalandpracticalresearch;in1910onthehydraulictransmission（hydrauliccoupling,hydraulictorqueconverter,etc.）contributions,sothatthesetwoareasofdevelopment.
TheSecondWorldWar（1941-1945）period,intheUnitedStates30%ofmachinetoolapplicationsinthehydraulictransmission.ItshouldbenotedthatthedevelopmentofhydraulictransmissioninJapanthanEuropeandtheUnitedStatesandothercountriesfornearly20yearslater.Beforeandafterin1955,therapiddevelopmentofJapan'shydraulicdrive,setupin1956,"HydraulicIndustry."Nearly20to30years,thedevelopmentofJapan'sfasthydraulictransmission,aworldleader.HydraulictransmissionTherearemanyoutstandingadvantages,itiswidelyused,suchasgeneralworkers.Plasticprocessingindustry,machinery,pressuremachinery,machinetools,etc.;operatingmachineryengineeringmachinery,constructionmachinery,agriculturalmachinery,automobiles,etc.;ironandsteelindustrymetallurgicalmachinery,liftingequipment,suchasrolleradjustmentdevice;civilwaterprojectswithfloodcontrolthedamgatesanddevices,bedliftsinstallations,bridgesandothermanipulationofinstitutions;speedturbinepowerplant
installations,nuclearpowerplants,etc.;shipdeckcrane（winch）,thebowdoors,bulkheadvalves,suchasthesternthruster;specialantennatechnologygiantwithcontroldevices,measurementbuoys,movementssuchasrotatingstage;
military-industrialcontroldevicesusedinartillery,shipanti-rollingdevices,aircraftsimulation,aircraftretractablelandinggearandruddercontroldevicesandotherdevices.
1.Chapter2（P31）
Unit2CastIrons
Inordertounderstandthefabricatingcharacteristicsofcastirons,itisnecessarytobeefamiliarwiththecharacteristicsofthemetalandthevarioustypesandclassificationsthatareavailable.为了了解铸铁的制造特性，它是要熟悉的金属的特性和各种可用的类型和分类
Oneofthedistinguishingfeaturesofallironsisthattheyhavearelativelyhighcarboncontent.Steelsrangeuptoabout2%carbon.Castironsoverlapwiththesteelssomewhatandrangefromabout1.5%upto5%carbon.Itisprincipallytheformofthecarbon,withisgovernedbythermalconditionsandalloyingelements,thatprovidesvariousstructuresthatmaybeclassifiedintothefollowingmaintype：
graycastiron;whitecastiron;ductile（nodular）graphiteirons;pacted（vermicular）graphiteiron.所有熨斗的一个显着特点是，它们具有相对高的碳含量。
钢可达至约2％的碳。
铸铁重叠有所钢和范围从约1.5％至5％的碳。
是主要的形式的碳，是由热条件和合金元素，提供了各种结构的主要类型如下：
灰铸铁，白口铸铁，球墨铸铁（结节）石墨铸铁;压实可分为（蠕）石墨铸铁。
Graycastiron.Thetermsgrayandwhitecastironrefertotheappearanceofthefracturedarea.Thegraycastironhasagrayishappearancebecauseofthelargeamountofflakegraphiteonthesurface.Thedarksectionsshowthegraphiteflake.Thepearlitetypemaybemadefinebyfastercooling,orcoarsebyslowcooling.Thesizeofthesectionwillalsodeterminethestructureofthemetal;thethinnerthesectionthefasteritcools.Thusacastinghavinglargevariayionsinsectionwillalsohavelargevariationsinhardnessandstrengthunlessspecialprecautionsaretaketoensureuniformcooling.灰铸铁。
的条款灰色和白色的铸铁是指裂缝区域的外观。
灰口铸铁的，因为大量的鳞片状石墨的表面上有一个浅灰色的外观。
暗部显示的鳞片石墨。
珠光体类型可能被罚款降温快，缓慢冷却或粗。
的部分的大小也将决定结构的金属部分较薄的冷却速度就越快。
因此，具有大的变化部分的铸造硬度和强度也将有大的变化，除非采取特殊的预防措施，以确保均匀的冷却。
Thebasicpositionofgraycastironsisoftendescribedintermsofcarbonequivalent（CE）.Thisfactorgivestherelationshipofthepercentageofcarbonandsiliconintheirontocapacitytoproducegraphite.灰口铸铁的基本组成中的碳当量（CE）通常被描述。
此因子给出能力生产石墨碳和硅中的铁的百分比的关系。
CE=c1+1/3（%si+%p）
Where:
ct=totalpercentagecarbonTheCEvaluemaythenberelatedtothetensilestrengthofthemetal.Ironswithacarbonequivalentofover4.3%arecalledhypereutecticandareparticularlygoodforthermal-shockresistance,suchasforingotmolds.Thehigherstrengthgrayirons.WithCElessthan4.3%,aretermedhypoeutectic.其中：
克拉=百分比碳的CE值然后可将有关的金属的拉伸强度。
铁杆具有4.3％以上的碳当量被称为过共晶和特别良好的抗热震性，如锭模。
高强度灰铸铁。
随着CE小于4.3％，被称为亚共晶。
Thepressivestrengthofgraycastironistooneitsoutstandingfeatures.Ingeneral,itrangesfrom3to5timesthetensilestrength.Asanexample,aclass-20graycastironwhichhasatensilestrengthof20,000psihasapressivestrengthof83,000psi.灰铸铁的抗压强度是一个突出的特点。
在一般情况下，它的范围从3至5倍的拉伸强度。
作为一个例子，它具有的拉伸强度为20,000psi的一类20灰铸铁的压缩强度为83,000psi。
Graycastironisthemostwidelyusedofallcastmetals.Typicalapplicationsareengineblocks,pipesandfittings,agriculturalimplements,bathtubs,householdappliances,electricmotorhousings,machinetools,etc.灰口铸铁是最广泛使用的所有铸造金属。
典型的应用是发动机缸体，管材和管件，农具，浴缸，家用电器，电机外壳，机床等。
2.Chapter2（p46）
Unit5HeatTreatmentofToolSteel
Thepurposeofheattreatmentistocontrolthepropertiesofametaloralloythroughthealterationofthestructureofthemetaloralloybyheatingittodefinite（一定的、确定的）temperaturesandcoolingatvariousrates.（热处理是通过加热确定金属或者合金的温度和不同速度冷却来改变它们的结构，以达到控制其性能的目的。
）Thisbination（组合）ofheatingandcontrolledcoolingdeterminesnotonlythenatureanddistribution（分布）ofthemicroconstituents（微组织）,whichinturndeterminetheproperties,butalsothegram（晶粒）size.（这种加热和冷却控制相结合的方法不仅决定了微观组织的性质和分布，进而决定了材料的性能，而且也决定了晶粒尺寸。
）
Heattreatingshouldimprovethealloyormetalfortheserviceintended.（热处理根据需要改变金属或者合金的性质。
）Someofthevariouspurposesofheattreatingareasfollows:
（热处理有以下不同的用途：
）
1.Toremovestrains应变aftercoldworking.（通过冷加工去除应变）
2.2.Toremoveinternalstressessuchasthoseproducedbydrawing,bending,orwelding.（通过拉深、弯曲或者焊接等方法去除内应力）
3.Toincreasethehardnessofthematerial.（提高材料的硬度）
4.Toimprovemachinability.（提高材料的切削性能）
5.Toimprovethecuttingcapabilitiesoftools.（提高刀具的切削能力）
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