機械加工工藝裝備夾具外文文獻翻譯@中英文翻譯@外文翻譯

1、外語文獻翻譯摘自:《制造工程與技術(shù)（機加工）》（英文版）《ManufacturingEngineeringTechnology—Machining》機械工業(yè)出版社2004年3月第1版頁—564560P美s.卡爾帕基安(Seropekalpakjian)s.r施密德(StevenR.Sch)著原文：20.9MACHINABILITYThemachinabilityofamaterialusuallydefinedintermsoffour

2、facts:1、Surfacefinishintegrityofthemachinedpart2、Toollifeobtained3、Fcepowerrequirements4、Chipcontrol.Thusgoodmachinabilitygoodsurfacefinishintegritylongtoollifelowfcepowerrequirements.Asfchipcontrollongthin(stringy)cured

3、chipsifnotbrokenupcanseverelyinterferewiththecuttingoperationbybecomingentangledinthecuttingzone.Becauseofthecomplexnatureofcuttingoperationsitisdifficulttoestablishrelationshipsthatquantitativelydefinethemachinabilityof

4、amaterial.Inmanufacturingplantstoollifesurfaceroughnessaregenerallyconsideredtobethemostimptantfactsinmachinability.Althoughnotusedmuchanymeapproximatemachinabilityratingsareavailableintheexamplebelow.20.9.1Machinability

5、OfSteelsBecausesteelsareamongthemostimptantengineeringmaterials(asnotedinChapter5)theirmachinabilityhasbeenstudiedextensively.Themachinabilityofsteelshasbeenmainlyimprovedbyaddingleadsulfurtoobtainsocalledfreemachiningst

6、eels.ResulfurizedRephosphizedsteels.Sulfurinsteelsfmsmanganesesulfideinclusions(secondphaseparticles)whichactasstressraisersintheprimarywear.Temperatureiscrespondinglyreduced.Consequentlythesesteelsproducelesscraterweare

7、speciallyathighcuttingspeeds.StainlessSteels.Austenitic(300series)steelsaregenerallydifficulttomachine.Chattercanbesproblemnecessitatingmachinetoolswithhighstiffness.Howeverferriticstainlesssteels(also300series)havegoodm

8、achinability.Martensitic(400series)steelsareabrasivetendtofmabuiltupedgerequiretoolmaterialswithhighhothardnesscraterwearresistance.Precipitationhardeningstainlesssteelsarestrongabrasiverequiringhardabrasionresistanttool

9、materials.TheEffectsofOtherElementsinSteelsonMachinability.Thepresenceofaluminumsiliconinsteelsisalwaysharmfulbecausetheseelementscombinewithoxygentofmaluminumoxidesilicateswhicharehardabrasive.Thesecompoundsincreasetool

10、wearreducemachinability.Itisessentialtoproduceusecleansteels.Carbonmanganesehavevariouseffectsonthemachinabilityofsteelsdependingontheircomposition.Plainlowcarbonsteels(lessthan0.15%C)canproduceposurfacefinishbyfmingabui

11、ltupedge.Caststeelsaremeabrasivealthoughtheirmachinabilityissimilartothatofwroughtsteels.Tooldiesteelsareverydifficulttomachineusuallyrequireannealingpritomachining.Machinabilityofmoststeelsisimprovedbycoldwkingwhichhard

12、ensthematerialreducesthetendencyfbuiltupedgefmation.Otheralloyingelementssuchasnickelchromiummolybdenumvanadiumwhichimprovethepropertiesofsteelsgenerallyreducemachinability.Theeffectofbonisnegligible.Gaseouselementssucha

13、shydrogennitrogencanhaveparticularlydetrimentaleffectsonthepropertiesofsteel.Oxygenhasbeenshowntohaveastrongeffectontheaspectratioofthemanganesesulfideinclusionsthehighertheoxygencontentthelowertheaspectratiothehigherthe

14、machinability.Iningvariouselementstoimprovemachinabilityweshouldconsiderthepossibledetrimentaleffectsoftheseelementsonthepropertiesstrengthofthemachinedpartinservice.Atelevatedtemperaturesfexampleleadcausesembrittlemento

15、fsteels(liquidmetalembrittlementhotshtnessseeSection1.4.3)althoughatroomtemperatureithasnoeffectonmechanicalproperties.Sulfurcanseverelyreducethehotwkabilityofsteelsbecauseofthefmationofironsulfideunlesssufficientmangane