《TOFD检测（双语）》课件-26.不等厚工件TOFD检测

不等厚工件TOFD检测案例

CaseStudy:TOFDInspectionofUnequal-ThicknessComponentsTOFD检测技术

TOFDTestingTechnology案例背景

CaseBackground1不等厚工件检测工艺选择

SelectionoftheTOFDInspectionProcedureforUnequal-ThicknessComponents2工艺参数计算与设置

CalculationandSettingofInspectionParameters3不等厚工件TOFD检测流程TOFDInspectionProcessforUnequal-ThicknessComponents4关键控制要点

KeyControlPoints5知识目标

Knowledgeobjectives教学目标

Teachingobjectives某高压化工设备封头与筒体连接厚度差较大，筒体厚度30mm，封头厚度50mm，封头外表面采用削边过渡，过渡削边比例1∶4，材质Q345R，按照设计要求采用UT+TOFD检测工艺进行检测，TOFD检测标准为NB/T47013，检测等级B级，验收等级Ⅱ级。

Ahigh-pressurechemicalvesselhasasubstantialthicknessdifferenceatthejointbetweenitsheadandshell.Theshellis30mmthick,whiletheheadis50mmthick.Ataperedtransitionwithasloperatioof1:4ismachinedontheoutersurfaceofthehead.ThematerialisQ345R.Asrequiredbythedesigndocuments,thejointisinspectedusingacombinationofconventionalultrasonictestingandTOFD.TOFDinspectionisperformedinaccordancewithNB/T47013atInspectionLevelBandAcceptanceLevelII.案例背景CaseBackground根据设计文件要求的检测标准，不等厚工件按照NB/T47013标准进行TOFD检测，按NB/T47013标准要求，至少进行两次非平行扫查，和一次偏置非平行扫查，同时按照标准要求，对扫查面盲区及底面盲区进行补充检测。

Inaccordancewiththeinspectionstandardspecifiedinthedesigndocuments,theunequal-thicknessjointisinspectedusingTOFDinaccordancewithNB/T47013.Atleasttwononparallelscansandoneoffsetnonparallelscanarerequired.Supplementaryinspectionsshallalsobeperformedforthescanning-surfaceandback-walldeadzonesasrequiredbythestandard.非平行扫查1

NonparallelScan1非平行扫查2

NonparallelScan2TOFD检测工艺选择SelectionoftheTOFDInspectionProcedure方法：采用UT检测，对TOFD上下盲区进行补偿检测，对扫查面进行表面磁粉检测，对焊缝横向缺陷进行超声波检测。

SupplementaryInspectionMethods:ConventionalultrasonictestingisusedtosupplementTOFDcoverageofthenear-surfaceandnear-back-wallregions.Magneticparticletestingisperformedonthescanningsurface,andultrasonictestingisusedtodetecttransversewelddefects.非平行扫查1

NonparallelScan1非平行扫查2

NonparallelScan2TOFD检测工艺选择SelectionoftheTOFDInspectionProcedure偏置非平行扫查将聚焦位置放在焊缝融合线边缘，探头分别放置在两侧母材平齐的位置上进行扫查。

Foroffsetnonparallelscanning,thebeamintersectionpointispositionedattheedgeoftheweldfusionline.Theprobesarepositionedonthelevelportionsoftheparentmaterialonbothsidesoftheweldduringscanning.非平行扫查3

OffsetNonparallelScan3TOFD检测工艺选择SelectionoftheTOFDInspectionProcedure单分区厚度：0~30mm；

Singleinspectionzone:0–30mm;分区设置，依据NB/T47013标准推荐，三次扫查均采用单分区设置

Inspection-ZoneConfiguration.BasedontherecommendationsofNB/T47013,asingle-zoneconfigurationisusedforallthreescans工艺参数计算与设置CalculationandSettingofInspectionParameters01非平行扫查1选择：采用5MHz6mm直径探头，60度楔块；

NonparallelScan1:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof60°;非平行扫查2选择：采用5MHz6mm直径探头，70度楔块；

NonparallelScan2:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof70°;偏置非平行扫查3选择：采用5MHz6mm直径探头，70度楔块；

OffsetNonparallelScan3:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof70°;探头楔块参数选择，依据NB/T47013标准推荐探头楔块选择如下：

SelectionofProbeandWedgeParameters.BasedontherecommendationsofNB/T47013,thefollowingprobeandwedgeconfigurationsareselected:工艺参数计算与设置CalculationandSettingofInspectionParameters02探头中心间距为S′+S，h为聚焦深度（20mm），θ（60°）和γ（46°）分别为平面和非平面侧楔块的角度，a为焊缝宽度的一半（10mm）。

TheprobecenterspacingisS′+S.Here,histhebeamintersectiondepthof20mm;θ,equalto60°,andγ,equalto46°,aretherefractedanglesontheflatandtaperedsides,respectively;andaishalftheweldwidth,equalto10mm.聚焦深度及PCS计算

CalculationoftheBeamIntersectionDepthandPCSS’=24mmS=20*tan60°=35mm其中S’及S的宽度需要保证探头楔块完全在削边上，不得压住焊缝，影响检测效果。

ThevaluesofS′andSshallbeselectedsothateachprobewedgerestsentirelyonthetaperedorflatparent-metalsurfacewithoutoverlappingtheweld,ascontactwiththeweldmayadverselyaffecttheinspection.探头中心间距计算原理示意图

SchematicDiagramoftheProbeCenterSpacingCalculation工艺参数计算与设置CalculationandSettingofInspectionParameters03平行扫查1聚焦深度及PCS计算如下：

ThebeamintersectiondepthandPCSforNonparallelScan1arecalculatedasfollows:探头中心间距为S′+S，h为聚焦深度（20mm），楔块的角度为70°。

TheprobecenterspacingisS′+S.Here,histhebeamintersectiondepthof20mm,andtherefractedangleis70°.S‘=（20+20）*tan70°=110S=20*tan70°=55探头中心间距计算原理示意图

SchematicDiagramoftheProbeCenterSpacingCalculation工艺参数计算与设置CalculationandSettingofInspectionParameters非平行扫查2聚焦深度及PCS计算如下：

ThebeamintersectiondepthandPCSforNonparallelScan2arecalculatedasfollows:聚焦深度及PCS计算

CalculationoftheBeamIntersectionDepthandPCS03探头中心间距为S′+S，h为聚焦深度（20mm），楔块的角度为70°。

TheprobecenterspacingisS′+S.Here,histhebeamintersectiondepthof20mm,andtherefractedangleis70°.S‘=（20+20）*tan70°=110S=20*tan70°=55偏置距离为10mm

Theoffsetdistanceis10mm探头中心间距计算原理示意图

SchematicDiagramoftheProbeCenterSpacingCalculation工艺参数计算与设置CalculationandSettingofInspectionParameters聚焦深度及PCS计算

CalculationoftheBeamIntersectionDepthandPCS03偏置非平行扫查3聚焦深度及PCS计算如下：

ThebeamintersectiondepthandPCSforOffsetNonparallelScan3arecalculatedasfollows:非平行扫查1：采用5MHz6mm直径探头，60度楔块。

NonparallelScan1:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof60°areused.非平行扫查2：采用5MHz6mm直径探头，70度楔块。

NonparallelScan2:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof70°areused.偏置非平行扫查3：采用5MHz6mm直径探头，70度楔块。

OffsetNonparallelScan3:5MHzprobeswithanelementdiameterof6mmandwedgesproducingarefractedangleof70°areused.探头校准及灵敏度设置，编码器校准，-12dB扩散角测定：

ProbeCalibrationandSensitivitySetting,EncoderCalibration,andMeasurementofthe−12dBBeamSpreadAngle:工艺参数计算与设置CalculationandSettingofInspectionParameters04用TOFD校准试块、对比试块校准声速、楔块延迟、深度校准与灵敏度设置，确保直通波，底波，一次变形波正常显示，且直通波前端和一次变形波后端保留0.5μs宽度以上数据。

UseTOFDcalibrationblocksandreferenceblockstoperformwave-velocitycalibration,wedge-delaycalibration,depthcalibration,andsensitivitysetting.Ensurethatthelateralwave,back-wallecho,andfirstmode-convertedsignalaredisplayedcorrectly.Theacquireddatashallextendatleast0.5μsbeforetheleadingedgeofthelateralwaveandatleast0.5μsbeyondthetrailingedgeofthefirstmode-convertedsignal.工艺参数计算与设置CalculationandSettingofInspectionParameters探头校准及灵敏度设置，编码器校准，-12dB扩散角测定：

ProbeCalibrationandSensitivitySetting,EncoderCalibration,andMeasurementofthe−12dBBeamSpreadAngle:04编码器单独进行校准，要求误差不超过1%，步进设置不大于1mm。

Calibratetheencoderseparately.Theencodererrorshallnotexceed1%,andthescanincrementshallnotexceed1mm.探头-12dB扩散角测定采用扩散角测定试块进行测量。

Measurethe−12dBbeamspreadangleoftheprobesusingabeam-spreadcalibrationblock.由于本工艺为非标准检测工艺，需要根据坡口样式进行试块加工验证，验证工艺合格后方可使用。

Becausethisisanonstandardinspectionprocedure,arepresentativereferenceblockshallbefabricatedaccordingtothegrooveconfigurationtoverifytheprocedure.Theprocedureshallnotbeuseduntilitssuitabilityhasbeenconfirmed.工艺参数计算与设置CalculationandSettingofInspectionParameters探头校准及灵敏度设置，编码器校准，-12dB扩散角测定：

ProbeCalibrationandSensitivitySetting,EncoderCalibration,andMeasurementofthe−12dBBeamSpreadAngle:04扫查面盲区：采用扫查面盲区试块进行测定；盲区采用超声波检测补偿。

Scanning-surfacedeadzone:Determinethedead-zonedepthusingascanning-surfacedead-zonereferenceblock,andinspectthedeadzoneusingsupplementaryultrasonictesting.底面盲区：由于非标准设置，底面盲区无法进行计算，因此采用直接补偿检测，采用常规超声波检测进行底面盲区补偿检测；

Back-WallDeadZone:Becausethenonstandardprobearrangementpreventstheback-walldead-zonedepthfrombeingcalculatedreliably,supplementaryconventionalultrasonictestingshallbeperformedtoinspectthisregion;扫查面盲区及底面盲区确定

DeterminationoftheScanning-SurfaceandBack-WallDeadZones工艺参数计算与设置CalculationandSettingofInspectionParameters05表面准备：清除焊缝两侧油污、铁锈，保证耦合稳定。

SurfacePreparation:Removeoil,rust,andothercontaminantsfrombothsidesoftheweldtoensurestablecoupling.数据扫查：分三次分别对不等厚工件进行TOFD扫查，采用水作为耦合剂，水泵供水，保证耦合稳定。单个数据长度不能大于2000mm，数据质量需连续观察，保证无数据丢失或灵敏度突变，保证数据采集质量。TOFD探头在削边检测时，确保行进偏移不能太大。

DataAcquisition:PerformthreeseparateTOFDscansoftheunequal-thicknessjoint.Usewatersuppliedbyapumpasthecouplanttomaintainstablecoupling.Thelengthofeachdatafileshallnotexceed2,000mm.Dataqualityshallbemonitoredcontinuouslytopreventdatalossorabruptchangesinsensitivityandtoensurereliabledataacquisition.WhentheTOFDprobestraveloverthetaperedtransition,thedeviationfromtheintendedscanpathshallbekepttoaminimum.缺陷识别与评定：采用TOFD评判软件对数据进行评判，对缺陷信号进行测定，包括深度、高度，长度等信息，对照标准判定等级，出具报告。

DefectIdentificationandEvaluation:UseTOFDevaluationsoftwaretoanalyzetheacquireddataandmeasuredefectparameters,includingdepth,height,andlength.Classifythedefectsinaccordancewiththeapplicablestandardandissuetheinspectionreport.不等厚工件TOFD检测流程TOFDInspectionProcessforUnequal-ThicknessComponents典型单分区数据显示

TypicalDataDisplayforSingle-ZoneInspection不等厚工件TOFD检测流程TOFDInspectionProcessforUnequal-ThicknessComponents扫查时应保证实际扫查路径与拟扫查路径的偏差不超过探头中心间距的10%。

Duringscanning,thedeviationoftheactualscanpathfromtheplannedscanpathshallnotexceed10%oftheprobecenterspacing.每次扫查长度不应超过2000mm；若需对焊缝在长度方向进行分段扫查，则各段扫查区的重叠范围至少为20mm；对于环焊缝，扫查停止位置应越过起始位置至少20mm，建议控制在100mm。

Thelengthofeachscanshallnotexceed2,000mm.Ifaweldisscannedinsectionsalongitslength,adjacentscannedsectionsshalloverlapbyatleast20mm.Foracircumferentialweld,thescanshallendatleast20mmbeyondthestartingposition,withanoverlapofapproximately100mmrecommended.关键控制要点KeyControlPoints扫查过程中应密切注意波幅状况，若发现直通波、底面反射波、材料晶粒噪声或波型转换波的波幅降低12dB以上或怀疑耦合不好时，应重新扫查整段区域；若发现直通波满屏或晶粒噪声波幅超过满屏高20%时，则应降低增益并重新扫查。

Signalamplitudesshallbecloselymonitoredthroughoutscanning.Iftheamplitudeofthelateralwave,back-wallecho,grainnoise,ormode-convertedwavedecreasesby12dBormore,orifpoorcouplingissuspected,theentireaffectedsectionshallberescanned.Ifthelateralwavereachesfull-screenheightorthegrain-noiseamplitudeexceeds20%offull-screenheight,reducethegainandrescanthesection.横向缺陷检测采用常规超声波按照NB/T47013.3中B级或C级的要求进行检测。

TransversewelddefectsshallbeinspectedusingconventionalultrasonictestinginaccordancewiththerequirementsforInspectionLevelBorCspecifiedinNB/T47013.3.由于属于非标准TOFD检测，随着PCS的增大，缺陷深度以及工件厚度的测量偏差随之增大，检测数据分析完缺陷定位定量建议采用常规超声波再次进行深度核实。

BecausethisisanonstandardTOFDinspection,measurementerrorsindefectdepthandworkpiecethicknessincreaseasthePCSincreases.AfterTOFDdataanalysisanddefectlocationandsizing,thedefectdepthshouldbeverifiedusingconventionalultrasonictesting.关键控制要点KeyContr