isChemicalanalysisofthefractureddifferentialmaterialwascarriedoutusingaspectrometer.ThechemicalcompositionofthematerialisgiveninTable.ChemicalcompositionshowsthatthematerialisalowalloycarburisingsteeloftheAISItype.Hardenabilityofthissteelisverylowbecauseoflowcarbonproportion.Therefore,surfaceareabecomeshardandhighlyenduring,andinnerareasbecomestoughbyincreasingcarbonproportiononthesurfaceareawithcementationoperation.Thisisthekindofsteelwhichisgenerallyusedinmechanicalpartssubjecteddotorsionandbending.Highresistanceisobtainedonthesurfaceandhighfatigueendurancevaluecanbeobtainedwithcompressiveresidualstressbymakingthesurfaceharder[–].Inwhichalloyelementsdistributethemselvesincarbonsteelsdependsprimarilyonthecompound-andcarbide-formingtendenciesofeachelement.Nickeldissolvesintheaferriteofthesteelsinceithaslesstendencytof以确定渗碳引起表面硬化带来横截面硬度值变化。
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