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1、Chapter2DefectAnalysis本章提要：缺陷分析是無損檢測的技術(shù)基礎(chǔ)。主要解決兩方面的問題：一是弄清defects’classification、propertyandharmfulness；二是分析thecausesofdefects，以便有效地Identifydefectsandeliminatedefects，提高工藝質(zhì)量。本章重點(diǎn)講授defects’classificationandharmfulness。缺陷的產(chǎn)生原因應(yīng)結(jié)合《材料成型原理》課程內(nèi)容深入理解與總結(jié)。最后，對Commonlyuseddetectionmetho
2、ds作簡要介紹。2.1Conceptandclassificationofprocessdefects2.1.1Conceptofprocessdefects（1）Whataretheprocessdefects？在材料加工成型過程中，經(jīng)常會出現(xiàn)某種或某些不合乎質(zhì)量要求的appearancedefect,propertydefectandorganizationdefect和更為嚴(yán)重的internalgeometricdefect（如cracks、pores、inclusions等）。我們把這些“metallurgicalfactors、stru
3、cturalfactorsandtechnologicalfactors”導(dǎo)致的產(chǎn)品質(zhì)量不符合相關(guān)參考標(biāo)準(zhǔn)的各類缺陷統(tǒng)稱為工藝缺陷。（2）Dialecticalanalysisofprocessdefects①Theabsolutenessofdefectgeneration——Inactualproduction,theacquirementoftheproductswithoutanydefectsisquitedifficult；Itisnoteconomicalorevenimpossibletomaketheproductsproduc
4、edinbatcheswithoutanydefects.②Therelativityofdefectevaluationstandards——Therelativityofwastestandards.Asforthesameofvariousparts,thequalityrequirementsaredifferentduetothedifferentworkingconditions.Therefore,thewastestandardsarealsodifferent.③Formulationprincipleofwastestanda
5、rds：Generallyspeaking,thehighertheproductqualitylevelis,thegreatertheriskafterfailurewillbe,andthecontrolofdefectsshouldbemorestrict.Therefore,Itisnecessarytopayattentiontotheimplementationandreferencetotherelevantstandards,whichisalsocalledtheprincipleoffitnessforpurpose.④Re
6、pairofprocessdefects：Minordefectthatdonotaffecttheapplicationcanbetolerated.Seriousdefectthatdonotmeettherequirementsmustbetreated.Somedefectscanberepairedintime,andsomedefectsmaynotberepairedwhichmustbesentencedtowaste.Examples比如：Excessivereinforcement，屬于焊縫形狀不良，嚴(yán)重時(shí)可以Grinding
7、；必要時(shí)grindedthereinforcementsmooth。再如：sandinclusiononthesurfaceofcasting，可以通過repairwelding來修復(fù)。特別指出，考慮到焊接接頭組織和性能的惡化，某些產(chǎn)品的weldingrepair不允許超過2次！所以，應(yīng)該注意formulatearigorousrepairprocess，否則就會造成Economicloss！2.1.2Classificationofprocessdefects工藝缺陷種類繁多，產(chǎn)生原因也相當(dāng)復(fù)雜。為了便于分析和處理工藝缺陷、制定檢驗(yàn)工藝、方便技
8、術(shù)交流，有必要對其進(jìn)行分類。(1)按technicalconnotation大體分為：①M(fèi)anufacturingandassembly
