材料的可機(jī)加工性-畢業(yè)設(shè)計(jì)機(jī)械外文翻譯

1、附錄附錄1：外文原文：外文原文TheimpregnabilityofmaterialTheimpregnabilityofamaterialusuallydefinedintermsoffourfacts:（1）.Surfacefinishintegrityofthemachinedpart（2）.Toollifeobtained（3）.Fcepowerrequirements（4）.Chipcontrol.Thusgoodimpreg

2、nabilitygoodsurfacefinishintegritylongtoollifelowfcepowerrequirements.Asfchipcontrollongthin(stringy)curedchipsifnotbrokenupcanseverelyinterferewiththecuttingoperationbybecomingentangledinthecuttingzone.Becauseofthecompl

3、exnatureofcuttingoperationsitisdifficulttoestablishrelationshipsthatquantitativelydefinetheimpregnabilityofamaterial.Inmanufacturingplantstoollifesurfaceroughnessaregenerallyconsideredtobethemostimptantfactsinimpregnabil

4、ity.Althoughnotusedmuchanymeapproximateimpregnabilityratingsareavailableintheexamplebelow.1.ImpregnabilityOfSteelsBecausesteelsareamongthemostimptantengineeringmaterialstheirimpregnabilityhasbeenstudiedextensively.Theimp

5、regnabilityofsteelshasbeenmainlyimprovedbyaddingleadsulfurtoobtainsocalledfreemachiningsteels.SulfuricReauthizedsteels.Sulfurinsteelsfmsmanganesesulfideinclusions(secondphaseparticles)whichactasstressraisersintheprimarys

6、hearzone.Asaresultthechipsproducedbreakupeasilyaresmallthisimprovesimpregnability.Thesizeshapedistributionconcentrationoftheseinclusionssignificantlyinfluenceimpregnability.Elementssuchastelluriumseleniumwhicharebothchem

7、icallysimilartosulfuractasinclusionmodifiersinSulfuricsteels.Phosphusinsteelshastwomajeffects.Itstrengthensthedeterringcausingincreasedhardness.Hardersteelsresultinbetterchipfmationsurfacefinish.(400series)steelsareabras

8、ivetendtofmabuiltupedgerequiretoolmaterialswithhighhothardnesscraterwearresistance.Precipitationhardeningstainlesssteelsarestrongabrasiverequiringhardabrasionresistanttoolmaterials.TheEffectsofOtherElementsinSteelsonMach

9、inability.Thepresenceofaluminumsiliconinsteelsisalwaysharmfulbecausetheseelementscombinewithoxygentofmaluminumoxidesilicateswhicharehardabrasive.Thesecompoundsincreasetoolwearreducemachinability.Itisessentialtoproduceuse

10、cleansteels.Carbonmanganesehavevariouseffectsonthemachinabilityofsteelsdependingontheircomposition.Plainlowcarbonsteels(lessthan0.15%C)canproduceposurfacefinishbyfmingabuiltupedge.Caststeelsaremeabrasivealthoughtheirmach

11、inabilityissimilartothatofwroughtsteels.Tooldiesteelsareverydifficulttomachineusuallyrequireannealingpritomachining.Machinabilityofmoststeelsisimprovedbycoldwkingwhichhardensthematerialreducesthetendencyfbuiltupedgefmati

12、on.Otheralloyingelementssuchasnickelchromiummolybdenumvanadiumwhichimprovethepropertiesofsteelsgenerallyreducemachinability.Theeffectofbonisnegligible.Gaseouselementssuchashydrogennitrogencanhaveparticularlydetrimentalef

13、fectsonthepropertiesofsteel.Oxygenhasbeenshowntohaveastrongeffectontheaspectratioofthemanganesesulfideinclusionsthehighertheoxygencontentthelowertheaspectratiothehigherthemachinability.Iningvariouselementstoimprovemachin

14、abilityweshouldconsiderthepossibledetrimentaleffectsoftheseelementsonthepropertiesstrengthofthemachinedpartinservice.Atelevatedtemperaturesfexampleleadcausesembrittlementofsteels(liquidmetalembrittlementhotshtness)althou

15、ghatroomtemperatureithasnoeffectonmechanicalproperties.Sulfurcanseverelyreducethehotwkabilityofsteelsbecauseofthefmationofironsulfideunlesssufficientmanganeseispresenttopreventsuchfmation.Atroomtemperaturethemechanicalpr