《TOFD检测（双语）》课件-25.压力管道TOFD检测

压力管道TOFD检测案例

CaseStudy:TOFDInspectionofPressurePipingTOFD检测技术

TOFDTestingTechnology案例背景

CaseBackground1压力管道检测工艺选择

SelectionoftheTOFDInspectionProcedureforPressurePiping2工艺参数计算与设置

CalculationandSettingofInspectionParameters3压力管道TOFD检测流程

TOFDInspectionProcessforPressurePiping4关键控制要点

KeyControlPoints5知识目标

Knowledgeobjectives教学目标

Teachingobjectives某项目压力管道外径914mm，壁厚21.4mm，焊接方法为半自动+氩弧焊打底的天然气管道焊缝，按照设计要求采用PAUT+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。

Anatural-gaspipelineinaconstructionprojecthasanoutsidediameterof914mmandawallthicknessof21.4mm.Theweldsareproducedbysemi-automaticweldingwithagastungstenarcwelding(GTAW)rootpass.Asrequiredbythedesigndocuments,theweldsareinspectedusingacombinationofPAUTandTOFD.TOFDinspectionisperformedinaccordancewithNB/T47013atInspectionLevelBandAcceptanceLevelII.表1压力管道技术参数

Table1TechnicalParametersofthePressurePiping项目

Item参数

Parameters项目

Item参数

Parameters管道

材质

PipeMaterialX65钢

X65Steel介质

ServiceMedium天然气

NaturalGas直径/mm

Diameter(mm)914设计单位

DesignOrganizationXXX设计温度/℃

DesignTemperature(°C)‌-20℃~60℃制造单位

ManufacturerXXX设计壁厚/mm

DesignWallThickness(mm)21.4安装单位

InstallationContractorXXX设计压力/MPa

DesignPressure(MPa)12MPa检测比例

ExtentofInspection100%TOFD+100%PAUT案例背景CaseBackground根据设计文件要求的检测标准，压力管道按照NB/T47013标准进行TOFD检测，按NB/T47013标准要求，厚度不超过50mm，单分区声场覆盖即可，采用非平行扫查检测工艺。按照标准要求，对扫查面盲区及底面盲区进行补充检测，本项目采用PAUT检测方法对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。

Inaccordancewiththeinspectionstandardspecifiedinthedesigndocuments,thepressurepipingisinspectedusingTOFDinaccordancewithNB/T47013.Becausethewallthicknessdoesnotexceed50mm,adequatesound-fieldcoveragecanbeachievedusingasingleinspectionzone.Anonparallelscanningprocedureisthereforeused.Asrequiredbythestandard,supplementaryinspectionsareperformedforthescanning-surfaceandback-walldeadzones.Inthisproject,PAUTisusedtosupplementTOFDcoverageofthenear-surfaceandnear-back-wallregions.Magneticparticletestingisperformedonthescanningsurface,andultrasonictestingisusedtodetecttransversewelddefects.TOFD检测工艺选择SelectionoftheTOFDInspectionProcedure单分区厚度：0~21.4mm

Singleinspectionzone:0–21.4mm分区设置，依据NB/T47013标准推荐，采用单分区设置

Inspection-ZoneConfiguration.BasedontherecommendationsofNB/T47013,asingle-zoneconfigurationisused工艺参数计算与设置CalculationandSettingofInspectionParameters01单分区：采用10MHz3mm直径探头，70度楔块；

Singleinspectionzone:10MHzprobeswithanelementdiameterof3mmandwedgesproducingarefractedangleof70°;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,thefollowingprobeandwedgeconfigurationisselected:工艺参数计算与设置CalculationandSettingofInspectionParameters02单分区：0~21.4mm（0~T），采用10MHz3mm直径探头，70度楔块；

Singleinspectionzone:0–21.4mm,correspondingto0–T;10MHzprobeswithanelementdiameterof3mmandwedgesproducingarefractedangleof70°areused;聚焦深度为分区厚度的2/3深度位置，即

Thebeamintersectiondepthissetattwo-thirdsofthezonethickness,namelyT=21.4*2/3=14.2mm;PCS=2*T*tan70°=78mm单分区聚焦深度及PCS计算如下：

CalculationoftheBeamIntersectionDepthandPCSfortheSingleInspectionZone:工艺参数计算与设置CalculationandSettingofInspectionParameters03单分区：0~21.4mm（0~T），采用10MHz3mm直径探头，70度楔块。

Singleinspectionzone:0–21.4mm,correspondingto0–T;10MHzprobeswithanelementdiameterof3mmandwedgesproducingarefractedangleof70°areused.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.探头-12dB扩散角测定采用扩散角测定试块进行测量。

Measurethe−12dBbeamspreadangleoftheprobesusingabeam-spreadcalibrationblock.探头校准及灵敏度设置，编码器校准，-12dB扩散角测定：

4ProbeCalibrationandSensitivitySetting,EncoderCalibration,andMeasurementofthe−12dBBeamSpreadAngle:工艺参数计算与设置CalculationandSettingofInspectionParameters04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：采用计算法确定；

Back-walldeadzone:Determinethedead-zonedepthbycalculation;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压力管道焊缝内焊缝表面宽度均为约4mm，热影响区10mm。

Theweldisapproximately4mmwideontheinnersurfaceofthepressurepiping,andtheheat-affectedzoneextends10mmfromtheweld.Δh=21.4(1-(1-（112/(392+21.42))1/2)=0.79mm底面盲区小于1mm，底面盲区可不予考虑，本项目采用PAUT覆盖TOFD上表面盲区。

Becausetheback-walldead-zonedepthislessthan1mm,nosupplementaryinspectionofthisregionisrequired.Inthisproject,PAUTisusedtoprovidesupplementarycoverageoftheTOFDscanning-surfacedeadzone.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：压力管道外表面作为TOFD扫查面，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。

DataAcquisition:UsetheoutersurfaceofthepressurepipingastheTOFDscanningsurface.Watersuppliedbyapumpisusedasthecouplanttomaintainstablecoupling.Thelengthofeachdatafileshallnotexceed2,000mm.Dataqualityshallbemonitoredcontinuouslytopreventdatalossorabruptchangesinsensitivityandtoensurereliabledataacquisition.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.压力管道TOFD检测流程TOFDInspectionProcessforPressurePiping典型单分区数据显示

TypicalDataDisplayforSingle-ZoneInspection压力管道TOFD检测流程TOFDInspectionProcessforPressurePiping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，本项目由于直径较大，整圈长度大于2米，因此分成两段进行扫查，每段长度约1.5米。

Thelengthofeachscanshallnotexceed2,000mm.Ifaweldisscannedinsectionsalongitslength,adjacentscannedsectionsshalloverlapbyatleast20mm.Foracircumferentialweld,thescanshallendatleast20mmbeyondthestartingposition,withanoverlapofapproximately100mmrecommended.Becausethepipediameterinthisprojectisrelativelylargeandthecircumferenceexceeds2m,theweldisdividedintotwoscanningsections,eachapproximately1.5mlong.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.关键控制要点KeyControlPoints01以直径914mm，厚度21.4mm压力管道为例，学习了压力管道TOFD检测单分区检测案例，明确方案原则、参数计算、扫查流程与覆盖验证要点。

Usingpressurepipingwithanoutsidediameterof914mmandawall