焊缝RT底片的评判规律及典型缺陷图谱.doc
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焊缝RT底片的评判规律及典型缺陷图谱.doc

焊缝RT底片的评判规律及典型缺陷图谱.doc

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焊缝射线照相底片得评判规律一、探伤人员要评片,四项指标放在先*,底片标记齐又正,铅字压缝为废片。ﻫ二、评片开始第一件,先找四条熔合线,小口径管照椭圆,根部都在圈里面。ﻫ三、气孔形象最明显,中心浓黑边缘浅,夹渣属于非金属,杂乱无章有棱边。四、咬边成线亦成点,似断似续常相见,这个缺陷最好定,位置就在熔合线。ﻫ五、未焊透就是大缺陷,典型图象成直线,间隙太小钝边厚,投影部位靠中间。六、内凹只在仰焊面,间隙太大就是关键,内凹未透要分清,内凹透度成弧线。ﻫ七、未熔合它斜又扁,常规透照难发现,它得位置有规律,都在坡口与层间。ﻫ八、横裂纵裂都危险,横裂多数在表面,纵裂分布范围广,中间稍宽两端尖。ﻫ九、还有一种冷裂纹,热影响区常发现,冷裂具有延迟性,焊完两天再拍片。十、有了裂纹很危险,斩草除根保安全,裂纹不论长与短,全部都就是Ⅳ级片。十一、未熔与也很危险,黑度有深亦有浅,一旦判定就就是它,亦就是全部Ⅳ级片。十二、危害缺陷未焊透,Ⅱ级焊缝不能有,管线根据深与长,容器跟着条渣走**。ﻫ十三、夹渣评定莫着忙,分清圆形与条状,长宽相比3为界,大于3倍就是条状。十四、气孔危害并不大,标准对它很宽大,长径折点套厚度,中间厚度插入法。十五、多种缺陷大会合,分门别类先评级,2类相加减去Ⅰ,3类相加减Ⅱ级。十六、评片要想快又准,下拜焊工当先生,要问诀窍有哪些,焊接工艺与投影。ﻫ注:*四项指标系底片得黑度、灵敏度、清晰度、灰雾度必须符合标准得要求。**指单面焊得管线焊缝与双面焊得容器焊缝内未焊透得判定标准。RadiographInterpretation-WeldsInadditiontoproducinghighqualityradiographs,theradiographermustalsobeskilledinradiographicinterpretation、Interpretationofradiographstakesplaceinthreebasicstepswhichare(1)detection,(2)interpretation,and(3)evaluation、Allofthesestepsmakeuseoftheradiographer'svisualacuity、Visualacuityistheabilitytoresolveaspatialpatterninanimage、Theabilityofanindividualtodetectdiscontinuitiesinradiographyisalsoaffectedbythelightingconditionintheplaceofviewing,andtheexperiencelevelforrecognizingvariousfeaturesintheimage、Thefollowingmaterialwasdevelopedtohelpstudentsdevelopanunderstandingofthetypesofdefectsfoundinweldmentsandhowtheyappearinaradiograph、DiscontinuitiesDiscontinuitiesareinterruptionsinthetypicalstructureofamaterial、Theseinterruptionsmayoccurinthebasemetal,weldmaterialor"heataffected"zones、Discontinuities,whichdonotmeettherequirementsofthecodesorspecificationusedtoinvokeandcontrolaninspection,arereferredtoasdefects、GeneralWeldingDiscontinuitiesThefollowingdiscontinuitiesaretypicalofalltypesofwelding、Coldlapisaconditionwheretheweldfillermetaldoesnotproperlyfusewiththebasemetalorthepreviousweldpassmaterial(interpasscoldlap)、Thearcdoesnotmeltthebasemetalsufficientlyandcausestheslightlymoltenpuddletoflowintobasematerialwithoutbonding、Porosity气孔istheresultofgasentrapmentinthesolidifyingmetal、Porositycantakema