金属的热处理 毕业论文外文文献翻译

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1、英文及翻译HeatTreatingofmetalsHeatingForthisdiscussion,IwilltakeyouthroughthehardeningprocessthatIuseonahighcarbonsteelblade,butfirstafewasides.Whenyouplacethesteelinthefireitbeginstogainheat.Thesteelwillbegintogiveoffvisiblecolorjustabove900Fitwillcontinuetopickupcoloruntilitreachesap

2、ointwhereitseemstohang.Itisstillgainingheat,butitisundergoinganinternaltransformationfromitscoldstructureintoametastableconditioncalledaustenite.Thispointatwhichitseemstohangiscalled decalescenceanditrepresentsthebottomofthecriticaltemperature.Itusuallybeginsaround1335FIncarbonste

3、eldependingonthecarboncontent.Onceitpassesthroughthispoint,thecrystalstructureofthesteelchangesastheferritereactswithsomeofthecarbideandbeginstopoolintoaustenite.Asthetemperatureincreasesmoreoftheaustenitewillbegintoforminotherplacesandcontinueuntilitreachesapoint10or15degreesabov

4、ethecriticaltemperaturewherealloftheferriteshouldbeconsumed.Atthispointthesteelshouldconsistofausteniteandundissolvedcarbides.Theaustenitegrainsstartfromasmallnucleusandcontinuetogrowuntiltheyimpingeonothergrowinggrains.Theinitialgrainsizeisestablishedatthispointandiftheexcesscarb

5、ideisinlargequantitiesitwillmaintainthissizewithlittleincrease,pinnedbythecarbide.Youcanseethistransformationifyouwatchthesteelcarefullyandbringthesteelupslowly.TheJapanesetalkedaboutwatchingtheshadowsonthebladeandquenchingwhentheshadowsturnedtoliquid.Ifyoutakethebladeoutofthefire

6、atthispointandwatchthecolorsdrop,youwillnoticeapointwherethesteelwillbrightenevenasitiscooling.Onataperedcrosssectionlikeaknifebladeitwillappeartotravelupfromtheedgetothespineoftheblade.Thisiscallrecalescenceandrepresentsthetransformationfromaustenitebacktopearlite.AfterIamdonefor

7、gingablade,Icyclethebladejustabovecriticalanddowntodarkheatatleastthreetimes.Iwatchforthesetwopointstoestablishcriticalinmymindandtosetupaveryfinegrainpearlitestructureinthesteel.Afterreachingcriticaltemperature,thesteelshouldbefullyaustenized,butthecarbideswillcontinuetodissolve.

8、Itmaybenecessarytosoakattemperatu