Casting_defect.pdf

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1、Castingdefect-Wikipedia,thefreeencyclopediaPage1of6CastingdefectFromWikipedia,thefreeencyclopediaAcastingdefectisanirregularityinthemetalcastingprocessthatisundesired.Somedefectscanbetoleratedwhileotherscanberepairedotherwisetheymustbeeliminated.Theyarebrokendownintofivemaincategories:gasporosity,sh

2、rinkagedefects,moldmaterialdefects,pouringmetaldefects,and[1]metallurgicaldefects.Contents■1Terminology■2Types■2.1Shrinkagedefects■2.2Gasporosity■2.3Pouringmetaldefects■2.4Metallurgicaldefects■3Processspecificdefects■3.1Diecasting■3.2Longitudinalfacialcrack■3.3Sandcasting■4Seealso■5References■5.1Bib

3、liographyTerminologyTheterms"defect"and"discontinuity"refertotwospecificandseparatethingsincastings.Defectsaredefinedasconditionsinacastingthatmustbecorrectedorremoved,orthecastingmustberejected.Discontinuities,alsoknownas"imperfections",aredefinedas"interruptionsinthephysicalcontinuityofthecasting"

4、.Therefore,ifthecastingisless-than-perfect,butstillusefulandintolerance,the[2]imperfectionsshouldbedeemed"discontinuities".TypesTherearemanytypesofdefectswhichresultfrommanydifferentcauses.Someofthesolutionsto[3]certaindefectscanbethecauseforanothertypeofdefect.Thefollowingdefectscanoccurinsandcasti

5、ngs.Mostofthesealsooccurinothercasingprocesses.ShrinkagedefectsShrinkagedefectsoccurwhenfeedmetalisnotavailabletocompensateforshrinkageasthemetalsolidifies.Shrinkagedefectscanbesplitintotwodifferenttypes:openshrinkagedefectsandclosedshrinkagedefects.Openshrinkagedefectsareopentotheatmosphere,therefo

6、reastheshrinkagecavityhttp://en.wikipedia.org/wiki/Casting_defect2011-5-18PDF文件使用"pdfFactoryPro"试用版本创建www.fineprint.cnCastingdefect-Wikipedia,thefreeencyclopediaPage2of6formsaircompensates.Therearetwotypesofopenairdefects:pipesandcavedsurfaces.Pipesformatthesurfaceofthecastingandburrowintothecasting

7、,whilecavedsurfacesareshallowcavitiesthat[4]formacrossthesurfaceofthecasting.Closedshrinkagedefects,alsoknownasshrinkageporosity,aredefectsthatformwithinthecasting.Isolatedpoolsofliquidforminsidesolid