常见焊接缺陷及检验方法汇总课件

常见焊接缺陷May.2010常见焊接缺陷May.2010一、焊接缺陷定义：在焊接过程中，在焊接接头中产生的不符合标准要求的缺陷，称为焊接缺陷。分类；依据GB6417—86<<金属熔化焊焊缝缺陷分类及说明>>,可将缺陷分为以下六类：裂纹孔穴固体夹杂未熔合和未焊透形状缺陷其他缺陷。一、焊接缺陷定义：焊接缺陷的特征及分布一、裂纹依照裂纹产生的温度范围划分：热裂纹：可分为结晶裂纹

液化裂纹

高温失塑裂纹（原因分析）冷裂纹：主要产生于焊接热影响区（氢的作用）在热裂纹：工件焊接后再次被加热到一定温度下（消应力热处理多层焊服役期）焊接缺陷的特征及分布一、裂纹母材中的夹层导致的裂纹由于板材在轧制过程中出现夹层，导致在焊接过程中出现裂纹：层状撕裂2010-1-114母材中的夹层导致的裂纹由于板材在轧制过程中出现夹层，导致在焊层状撕裂焊接工艺的调整接头形式的改善2010-1-115层状撕裂焊接工艺的调整接头形式的改善2010-1-11二、气孔定义：焊接熔池中的气泡在凝固时未能及时溢出，而留下来所形成的孔穴。分类：依形状分球形条虫形依分布分孤立均布依来源分析出型(分析原因)反应型（产生部位原因）［C］+［O］=CO［Fe］+［C］=［Fe］+CO［SiO2］+2［C］=［Si］+2CO防止措施：1限制熔池中气体的溶入或产生。（具体措施）2排除熔池中已溶入的气体。（具体措施）2010-1-116二、气孔定义：焊接熔池中的气泡在凝固时未能及时溢出，而三、固体夹杂1夹渣焊后残留在焊缝中的熔渣形状复杂一般呈线状、长条状、颗粒状及其他形式。部位主要发生在坡口边缘和每层焊道之间非圆滑过渡的部位。横焊、立焊或仰焊比平焊多。2夹钨钨极氩弧焊时，若钨极不慎与熔池接触，使钨的颗粒进入焊缝金属中。

在焊接镍铁合金时，形成钨合金，射线探伤很难发现。2010-1-117三、固体夹杂1夹渣焊后残留在焊缝中的熔渣2010四、未焊透和未熔合1未焊透焊接时母材金属之间应该熔合而未焊上的部分。部位：单面焊的坡口根部、双面焊的坡口钝边。危害：较大的应力集中，在其末端产生裂纹。2未熔合焊缝金属与母材、焊缝金属与焊道金属之间未完全熔化结合的部分。2010-1-118四、未焊透和未熔合1未焊透焊接时母材金属之间应该五、形状缺陷形状缺陷包括：1错边、角变形2咬边3焊瘤4烧穿和下塌5焊缝尺寸、形状不合要求6其他缺陷2010-1-119五、形状缺陷形状缺陷包括：2010-1-119错边定义：由于两个焊件没有对正而造成板的中心线平行偏差成因:粗心.不同厚度的母材焊接厚度过渡预防:改善工艺.改变厚度过渡的过度角度。修补:打磨.在错边不严重时可采用打磨的方法来处理（板材）.管材内部错边较难处理.错边定义：由于两个焊件没有对正而造成板的中心线平行偏差成因:咬边

定义:由于焊接参数选择或操作不当，沿焊趾的母材部位产生的沟槽或凹陷成因:电流过大、焊条角度不合适、电弧过长。预防措施:清除焊缝两侧铁锈焊接位置立焊仰焊时较易出现咬边的情况修补:选用较小的焊条、最好是打磨或挖凿后用低氢焊条来补焊.咬边

定义:由于焊接参数选择或操作不当，沿焊趾的母材部位产焊瘤定义:焊接过程中，熔化金属流淌到焊缝之外未熔化的母材上所形成的金属瘤。（图）位置:焊瘤存在于焊缝表面，在其下面往往伴随着未熔合、未焊透等缺陷。危害:由于金属的堆积使焊缝的几何形状发生变化，造成应力集中。焊瘤定义:焊接过程中，熔化金属流淌到焊缝之外未熔化的位置:烧穿和下塌定义：焊接过程中，熔化金属自坡口背面流出，形成穿孔的缺陷。烧穿易发生在第一道焊道及薄板对接焊缝或管子对接焊缝中。烧穿的周围常伴有气孔、夹渣焊瘤及未焊透等缺陷。下塌：穿过单层焊缝根部，或在多层焊接接头中穿过前道熔敷金属塌落的过量焊缝金属。（图）2010-1-1113烧穿和下塌定义：焊接过程中，熔化金属自坡口背面流出，不规则的焊缝尺寸、形状Concavity凹陷2010-1-1114不规则的焊缝尺寸、形状Concavity2010-1-111Convexity凸出2010-1-1115Convexity2010-1-1115其他缺陷1电弧擦伤2飞溅其他缺陷1电弧擦伤2010-1-11172010-1-1117二、焊接检验焊接检验的分类：

（1）破坏性检验

（2）非破坏性检验

（3）声发射检测二、焊接检验焊接检验的分类：无损检验射线检测超声检测磁粉检测渗透检测涡流检测2010-1-1119无损检验射线检测2010-1-1119射线检测射线探伤的实质根据被检工件与其内部缺陷介质对射线的衰减不同，而引起的射线透照之后到达底片上的强度不同，从而造成底片“感光”程度不同将缺陷在底片上反映出来。Someexamples(药皮、药渣、厚度方向缺陷不灵敏）2010-1-1120射线检测射线探伤的实质2010-1-1120射线的本质X射线

Γ射线

高频电磁波（光子）2010-1-1121射线的本质X射线2010-1-1121超声波检测超声波检测：是利用超声波在物体中的传播、反射和衰减等物理特性来发现缺陷的一种探伤方式。声波（人类的听觉）次声波（地震、核武器）超声波（0.5~10MHz）（图Example）探头（45平）耦合剂（探头不接触工件表面）2010-1-1122超声波检测超声波检测：是利用超声波在物体中的传播、反射和衰减渗透检测渗透检测：利用带有荧光染料或红色染料渗透剂的渗透作用，显示缺陷痕迹的无损检验方法。用途：用于各种金属材料和非金属材料构件表面开口缺陷的检验。2010-1-1123渗透检测渗透检测：利用带有荧光染料或红色染料渗透剂的渗透作用渗透检验的原理1毛细作用2两平行板间的毛细现象2010-1-1124渗透检验的原理1毛细作用2010-1-1124声发射探伤技术2010-1-1125声发射探伤技术2010-1-1125常见焊接缺陷及检验方法汇总课件常见焊接缺陷及检验方法汇总课件Removingarootpassbygrinding1.Recreatethegroovegeometryascloselyaspossible.2.Useasawordiegrinderand1.5mm/1/16”–3.0mm/1/8”cutoffwheeltorecreaterootopening.Rememberrepairsaresometimesrequiredtobemadewithasmallerelectrode.3.Openthegrooveangle.Becarefultoleavetheproperrootfacedimension.4.Featherthestartandstoptoblendsmoothlyintoandoutoftheexistingweld.Removingarootpassbygrindi常见焊接缺陷及检验方法汇总课件ExcessiveConcavityorConvexityDefinition:ConcavityorconvexityofafilletweldwhichexceedsthespecifiedallowablelimitsCause:AmperageandtravelspeedPrevention:Observeproperparametersandtechniques.Repair:Grindofforweldon.Mustblendsmoothlyintothebasemetal.ExcessiveConcavityorConvexiConcavityConcavityConvexityConvexityReinforcementExcessiveInsufficientImpropercontourFaceReinforcementRootReinforcementTheamountofagrooveweldwhichextendsbeyondthesurfaceoftheplateReinforcementExcessiveFaceReExcessiveReinforcementDefinition:Specificallydefinedbythestandard.Typically,Reinforcementshouldbeflushto1.5mm/1/16”(pipe)orflushto3.0mm/1/8”(plateorstructuralshapes).Cause:Travelspeedtooslow,amperagetoolowPrevention:Setamperageandtravelspeedonscrapplate.Repair:Removeexcessivereinforcementandfeathertheweldtoestoasmoothtransitiontothebaseplate.ExcessiveReinforcementDefinitDefinition:Specificallydefinedbythestandard.Typically,Underfillmaybeupto5%ofmetalthicknessnottoexceed0.80mm/1/32”aslongasthethicknessismadeupintheoppositereinforcement.Notappliedtofilletwelds.Cause:Onrootreinforcement-Toolittlefillermetalwillcausethinningofthefillermetal.InOHposition,toohotortoowidewillcausedroopingoftheopenrootpuddle.Prevention:Useproperweldingtechnique.Usebackingorconsumableinserts.Usebackweldorbacking.Repair:Possiblysimplyincreasethefacereinforcement.Ifbackweldingisnotpossible,mustremoveandreweld.InsufficientReinforcementDefinition:SpecificallydefinDefinition:Whentheweldexhibitslessthana1350transitionangleattheweldtoe.Cause:PoorweldingtechniquePrevention:Usepropertechniques.Aweaveorwhipmotioncanofteneliminatetheproblem.Repair:Theweldfacemustbefeatheredintothebaseplate.1350ImproperWeldContourDefinition:WhentheweldexhiOverlapDefinition:WhenthefaceoftheweldextendsbeyondthetoeoftheweldCause:Improperweldingtechnique.Typically,electrodeanglesandtravelspeed.Prevention:Overlapisacontourproblem.Properweldingtechniquewillpreventthisproblem.Repair:Overlapmustberemovedtoblendsmoothlyintothebasemetal.Becarefulofdeepgrindmarksthatruntransversetotheload.Alsobecarefuloffusiondiscontinuitieshiddenbygrinding.UseNDTtobesure.OverlapDefinition:WhenthefaOverlapOverlapismeasuredwithasquareedgesuchasa152.4mm/6”rule.Noamountofoverlapistypicallyallowed.Amountofoverlapnotdeterminedbycodes.OverlapOverlapismeasuredwitBurn-through(non-standard)Definition:Whenanundesirableopenholehasbeencompletelymeltedthroughthebasemetal.Theholemayormaynotbeleftopen.Cause:Excessiveheatinput.Prevention:Reduceheatinputbyincreasingtravelspeed,useofaheatsink,orbyreducingweldingparameters.Repair:Willbedefinedbystandards.Fillingmaysuffice.Otherwise,removalandreweldingmayberequired.Somestandardsmayrequirespecialfillermetaland/orPWHT.Burn-through(non-standard)DefIncompleteorInsufficientPenetrationDefinition:WhentheweldmetaldoesnotextendtotherequireddepthintothejointrootCause:Lowamperage,lowpreheat,tightrootopening,fasttravelspeed,shortarclength.Prevention:Correctthecontributingfactor(s).Repair:Backgougeandbackweldorremoveandreweld.IncompleteorInsufficientPenIncompleteFusionDefinition:Whereweldmetaldoesnotformacohesivebondwiththebasemetal.Cause:Lowamperage,steepelectrodeangles,fasttravelspeed,shortarcgap,lackofpreheat,electrodetoosmall,uncleanbasemetal,arcoffseam.Prevention:Eliminatethepotentialcauses.Repair:removeandreweld,beingcarefultocompletelyremovethedefectivearea.Thisissometimesextremelydifficulttofind.IncompleteFusionDefinition:WArcStrikeDefinition:Alocalizedcoalescenceoutsidetheweldzone.Inlaymenslanguage.Anareawhereanelectricarcscarredthebasemetalcausedbyelectrodearcorelectriccablebeingpulledacrossbasemetal.Cause:CarelessnessPrevention:Indifficultareas,adjacentareascanbeprotectedusingfireblankets.Repair:Whereapplicable,arcstrikesmustbegroundsmoothandtestedforcracks.Iffound,theymustberemoveandrepairedusingaqualifiedrepairprocedureandinspectedasanyotherweld.ArcStrikeDefinition:AlocaliInclusionsSlagWagontrackslinesofslagalongoneorbothsidesofbevelTungsten

InclusionsSlagDefinition:SlagentrappedwithintheweldCause:Lowamperage,impropertechnique,Tryingtoweldinanareathatistootight.SlowtravelinVerticalDownornotpositioningelectrodecorrectlyineitherupordownhandpositions.Prevention:Increaseamperageorpreheat,grindouttightareastogainaccesstobottomofjoint,positionelectrodecorrectly.Repair:Removebygrinding.Reweld.SlagInclusionDefinition:SlagentrappedwitDefinition:Slangtermforagrooveleftatthetoeofarootpasswhichbecomesfilledwithslagandistrappedintheweld.Cause:Thecontouroftherootpassistoohigh,ortheweldtoeisnotbondedtothebasemetalPrevention:Usepropertechniquetodeposittheweldroot.Repair:Bestrepairedbeforeapplyingthehotpass.Carefullygrindtherootpassfaceflat.becarefulnottogougeotherareasontheweldment.WagonTracks(non-standard)Definition:SlangtermforagDefinition:Atungstenparticleembeddedinaweld.(TypicallyGTAWonly)Cause:Tungstenelectrodetoosmall,amperagetoohigh,ACbalanceon+,Upslopetoohigh,electrodetipnotproperlyground,electrodedippedintotheweldpoolortouchedwiththefillrod,electrodesplit.Prevention:EliminatethecauseRepair:GrindoutandreweldTungstenInclusionDefinition:AtungstenparticlInclusionsFixwhenyouseeit.Otherwisegrindout&fixwhenfoundtobeunacceptablebynon-destructiveexaminations.InclusionsFixwhenyouseeit.Whiskers,Grapes,orExcessivePushThroughUnsightlyInhibitsmaterialflowinpipingAreinclusionsCanbreakoffinpipesanddamageequipmentdownlineWhiskers,Grapes,orExcessiveSpatterDefinition:Smallparticlesofweldmetalexpelledfromtheweldingoperationwhichadheretothebasemetalsurface.Cause:Longarclength,severeelectrodeangles,highamperages.Prevention:Correctthecause.Basemetalcanbeprotectedwithcoveringsorhi-temppaintsorothermeans.Repair:Removebygrindingorsanding.SpatterDefinition:SmallpartiArcCratersDefinition:Adepressionleftattheterminationoftheweldwheretheweldpoolisleftunfilled.Cause:ImproperweldterminationtechniquesPrevention:Pauseatthispointandallowtofillpriortobreakingarc.Repair:Ifnocracksexist,simplyfillinthecrater.Generallyweldingfrombeyondthecraterbackintothecrater.ArcCratersDefinition:AdepreCracksLongitudinalTransverseCraterThroatToeRootUnderbeadandHeat-affectedzoneHotColdordelayedCracksLongitudinalDefinition:Acrackrunninginthedirectionoftheweldaxis.Maybefoundintheweldorbasemetal.Cause:Preheatorfastcoolingproblem.Alsocausedbyshrinkagestressesinhighconstraintareas.Prevention:Weldtowardareasoflessconstraint.Alsopreheattoevenoutthecoolingrates.Repair:RemoveandreweldLongitudinalCrackDefinition:AcrackrunninginDefinition:Acrackrunningintoorinsideaweld,transversetotheweldaxisdirection.Cause:WeldmetalhardnessproblemPrevention:Repair:TransverseCrackDefinition:AcrackrunninginDefinition:Acrack,generallyintheshapeofan“X”whichisfoundinacrater.Cratercracksarehotcracks.Cause:Thecenteroftheweldpoolbecomessolidbeforetheoutsideoftheweldpool,pullingthecenterapartduringcoolingoftheoutside.Prevention:Usecraterfill,fillthecrateratweldterminationand/orpreheattoevenoutthecoolingofthepuddleRepair:CraterCrackDefinition:Acrack,generallyDefinition:Alongitudinalcracklocatedintheweldthroatarea.Cause:TransverseStresses,probablyfromshrinkage.Indicatesinadequatefillermetalselectionorweldingprocedure.Maybeduetocratercrackpropagation.Prevention:Correctinitialcause.Increasingpreheatmaypreventit.besurenottoleaveacrater.Useamoreductilefillermaterial.Repair:Removeandreweldusingappropriateprocedure.Besuretocorrectinitialproblemfirst.ThroatCrackDefinition:AlongitudinalcraDefinition:AcrackinthebasemetalbeginningatthetoeoftheweldCause:Transverseshrinkagestresses.IndicatesaHAZbrittlenessproblem.Prevention:Increasepreheatifpossible,oruseamoreductilefillermaterial.Repair:ToeCrackDefinition:AcrackinthebasDefinition:Acrackintheweldattheweldroot.Cause:Transverseshrinkagestresses.Sameasathroatcrack.Prevention:SameasathroatcrackRepair:RootCrackDefinition:AcrackinthewelDefinition:AcrackintheunmeltedparentmetaloftheHAZ.Cause:HydrogenembrittlementPrevention:UseLo/Hielectrodesand/orpreheatRepair:(onlyfoundusingNDT).Removeandreweld.UnderbeadCrackDefinition:AcrackintheunmDefinition:Acrackintheweldthatoccursduringsolidification.Cause:Microstressesfromweldmetalshrinkagepullingapartweldmetalasitcoolsfromliquidtosolidtemp.Prevention:Preheatorusealowtensilfillermaterial.Repair:HotCrackDefinition:AcrackinthewelDefinition:AcrackthatoccursafterthemetalhascompletelysolidifiedCause:Shrinkage,Highlyrestrainedwelds,DiscontinuitiesPrevention:Preheat,weldtowardareasoflessconstraint,useamoreductileweldmetalRepair:Removeandreweld,correctproblemfirst,preheatmaybenecessary.ColdCrackDefinition:AcrackthatoccurRepairstoCracksDeterminethecauseCorrecttheproblemTakeprecautionstopreventreoccurrenceGenerallyrequiredtorepairusingasmallerelectrodeRepairstoCracksDeterminetheBaseMetalDiscontinuitiesLamellartearingLaminationsandDelaminationsLapsandSeamsBaseMetalDiscontinuitiesLameLaminationsBaseMetalDiscontinuityMayrequirerepairpriortoweldingFormedduringthemillingprocessLaminationsBaseMetalDiscontiLaminationeffectscanbereducedbyjointdesign:LaminationeffectscanbereduDelaminationsDelaminationsLapsandSeamsAmill-induceddiscontinuityinwhichresultsfromalumpofmetalbeingsqueezedoverintothesurfaceofthematerial.Ifbeyondacceptablelimits,mustberemovedandrepairedordiscarded.LapsandSeamsAmill-induceddPorositySinglePoreUniformlyScatteredClusterLinearPipingPorositySinglePoreSinglePoreSeparatedbyatleasttheirowndiameteralongtheaxisoftheweldSinglePoreSeparatedbyatleaUniformlyScatteredPorosityTypicallyjudgedbydiameterandproximitytoastartorstopoftencausedbylowamperageorshortarcgaporanunshieldedweldstartUniformlyScatteredPorosityTyClusterPorosityTypicallyviewedasasinglelargediscontinuityClusterPorosityTypicallyviewLinearPorositybeinglineargreatlyaffectstheseverityofthisdiscontinuityLinearPorositybeinglineargrPipingPorosityGenerallyhasspecialallowablelimitsPipingPorosityGenerallyhassPorositypreheatwillhelpeliminatemayneedanelectrodewithmoredeoxidizersUserun-on/run-offtapsrestartontopofpreviousweldandgrindofflumpPorositypreheatwillhelpeliHeat-affectedzonemicrostructurealterationadddrawingofHAZofgrooveweldwithleadersto:grainrefinementgraingrowthhardenedareassoftenedareasprecipitatesuseptableareas.Heat-affectedzonemicrostructSizeordimensionIfitrendersthepartunusable,itisadefect.Ifitisoutsidetheallowablelimit,itrendersthepartunusable.Thingsdon’thavetobeperfect,justwithintheacceptabletolerance.WorkingtoperfectionistootimeconsumingandcostlySizeordimensionIfitrendersHammermarksStressrisersUnsightlyUnnecessaryHammermarksStressrisersREPAIRTECHNIQUESMayinvolve:differentprocessdifferentproceduredifferentpreheat/PWHTdifferentelectrodesmallerelectrodeREPAIRTECHNIQUESMayinvolve:Onlyrepairdefects.Discontinuitiesare,bydefinition,acceptable.Repairisthereforeunnecessaryandnotcosteffective.Onlyrepairdefects.DiscontinInspectionToolsInspectionToolsFilletWeldSize-Forequallegfilletwelds,theleglengthsofthelargestisoscelesrighttrianglethatcanbeinscribedwithinthefilletweldcrosssection.Forunequallegfilletwelds,theleglengthsofthelargestrighttrianglethatcanbeinscribedwithinthefilletweldcrosssectionMeasuringWeldSizesFilletWeldSize-ForequallFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageFibreMetalFilletGageUndercutGuageGalGageCo.UndercutGuageGalGageCo.PalmgrinGuagePalmgrinGuageMagnifyingGlassUsedtoreadsmallscalesMagnifyingGlassUsedtoreadsFlashlightUsedtocastshadowstofindporosity,undercutandoverlap.FlashlightUsedtocastshadows常见焊接缺陷及检验方法汇总课件常见焊接缺陷May.2010常见焊接缺陷May.2010一、焊接缺陷定义：在焊接过程中，在焊接接头中产生的不符合标准要求的缺陷，称为焊接缺陷。分类；依据GB6417—86<<金属熔化焊焊缝缺陷分类及说明>>,可将缺陷分为以下六类：裂纹孔穴固体夹杂未熔合和未焊透形状缺陷其他缺陷。一、焊接缺陷定义：焊接缺陷的特征及分布一、裂纹依照裂纹产生的温度范围划分：热裂纹：可分为结晶裂纹

液化裂纹

高温失塑裂纹（原因分析）冷裂纹：主要产生于焊接热影响区（氢的作用）在热裂纹：工件焊接后再次被加热到一定温度下（消应力热处理多层焊服役期）焊接缺陷的特征及分布一、裂纹母材中的夹层导致的裂纹由于板材在轧制过程中出现夹层，导致在焊接过程中出现裂纹：层状撕裂2010-1-1197母材中的夹层导致的裂纹由于板材在轧制过程中出现夹层，导致在焊层状撕裂焊接工艺的调整接头形式的改善2010-1-1198层状撕裂焊接工艺的调整接头形式的改善2010-1-11二、气孔定义：焊接熔池中的气泡在凝固时未能及时溢出，而留下来所形成的孔穴。分类：依形状分球形条虫形依分布分孤立均布依来源分析出型(分析原因)反应型（产生部位原因）［C］+［O］=CO［Fe］+［C］=［Fe］+CO［SiO2］+2［C］=［Si］+2CO防止措施：1限制熔池中气体的溶入或产生。（具体措施）2排除熔池中已溶入的气体。（具体措施）2010-1-1199二、气孔定义：焊接熔池中的气泡在凝固时未能及时溢出，而三、固体夹杂1夹渣焊后残留在焊缝中的熔渣形状复杂一般呈线状、长条状、颗粒状及其他形式。部位主要发生在坡口边缘和每层焊道之间非圆滑过渡的部位。横焊、立焊或仰焊比平焊多。2夹钨钨极氩弧焊时，若钨极不慎与熔池接触，使钨的颗粒进入焊缝金属中。

在焊接镍铁合金时，形成钨合金，射线探伤很难发现。2010-1-11100三、固体夹杂1夹渣焊后残留在焊缝中的熔渣2010四、未焊透和未熔合1未焊透焊接时母材金属之间应该熔合而未焊上的部分。部位：单面焊的坡口根部、双面焊的坡口钝边。危害：较大的应力集中，在其末端产生裂纹。2未熔合焊缝金属与母材、焊缝金属与焊道金属之间未完全熔化结合的部分。2010-1-11101四、未焊透和未熔合1未焊透焊接时母材金属之间应该五、形状缺陷形状缺陷包括：1错边、角变形2咬边3焊瘤4烧穿和下塌5焊缝尺寸、形状不合要求6其他缺陷2010-1-11102五、形状缺陷形状缺陷包括：2010-1-119错边定义：由于两个焊件没有对正而造成板的中心线平行偏差成因:粗心.不同厚度的母材焊接厚度过渡预防:改善工艺.改变厚度过渡的过度角度。修补:打磨.在错边不严重时可采用打磨的方法来处理（板材）.管材内部错边较难处理.错边定义：由于两个焊件没有对正而造成板的中心线平行偏差成因:咬边

定义:由于焊接参数选择或操作不当，沿焊趾的母材部位产生的沟槽或凹陷成因:电流过大、焊条角度不合适、电弧过长。预防措施:清除焊缝两侧铁锈焊接位置立焊仰焊时较易出现咬边的情况修补:选用较小的焊条、最好是打磨或挖凿后用低氢焊条来补焊.咬边

定义:由于焊接参数选择或操作不当，沿焊趾的母材部位产焊瘤定义:焊接过程中，熔化金属流淌到焊缝之外未熔化的母材上所形成的金属瘤。（图）位置:焊瘤存在于焊缝表面，在其下面往往伴随着未熔合、未焊透等缺陷。危害:由于金属的堆积使焊缝的几何形状发生变化，造成应力集中。焊瘤定义:焊接过程中，熔化金属流淌到焊缝之外未熔化的位置:烧穿和下塌定义：焊接过程中，熔化金属自坡口背面流出，形成穿孔的缺陷。烧穿易发生在第一道焊道及薄板对接焊缝或管子对接焊缝中。烧穿的周围常伴有气孔、夹渣焊瘤及未焊透等缺陷。下塌：穿过单层焊缝根部，或在多层焊接接头中穿过前道熔敷金属塌落的过量焊缝金属。（图）2010-1-11106烧穿和下塌定义：焊接过程中，熔化金属自坡口背面流出，不规则的焊缝尺寸、形状Concavity凹陷2010-1-11107不规则的焊缝尺寸、形状Concavity2010-1-111Convexity凸出2010-1-11108Convexity2010-1-1115其他缺陷1电弧擦伤2飞溅其他缺陷1电弧擦伤2010-1-111102010-1-1117二、焊接检验焊接检验的分类：

（1）破坏性检验

（2）非破坏性检验

（3）声发射检测二、焊接检验焊接检验的分类：无损检验射线检测超声检测磁粉检测渗透检测涡流检测2010-1-11112无损检验射线检测2010-1-1119射线检测射线探伤的实质根据被检工件与其内部缺陷介质对射线的衰减不同，而引起的射线透照之后到达底片上的强度不同，从而造成底片“感光”程度不同将缺陷在底片上反映出来。Someexamples(药皮、药渣、厚度方向缺陷不灵敏）2010-1-11113射线检测射线探伤的实质2010-1-1120射线的本质X射线

Γ射线

高频电磁波（光子）2010-1-11114射线的本质X射线2010-1-1121超声波检测超声波检测：是利用超声波在物体中的传播、反射和衰减等物理特性来发现缺陷的一种探伤方式。声波（人类的听觉）次声波（地震、核武器）超声波（0.5~10MHz）（图Example）探头（45平）耦合剂（探头不接触工件表面）2010-1-11115超声波检测超声波检测：是利用超声波在物体中的传播、反射和衰减渗透检测渗透检测：利用带有荧光染料或红色染料渗透剂的渗透作用，显示缺陷痕迹的无损检验方法。用途：用于各种金属材料和非金属材料构件表面开口缺陷的检验。2010-1-11116渗透检测渗透检测：利用带有荧光染料或红色染料渗透剂的渗透作用渗透检验的原理1毛细作用2两平行板间的毛细现象2010-1-11117渗透检验的原理1毛细作用2010-1-1124声发射探伤技术2010-1-11118声发射探伤技术2010-1-1125常见焊接缺陷及检验方法汇总课件常见焊接缺陷及检验方法汇总课件Removingarootpassbygrinding1.Recreatethegroovegeometryascloselyaspossible.2.Useasawordiegrinderand1.5mm/1/16”–3.0mm/1/8”cutoffwheeltorecreaterootopening.Rememberrepairsaresometimesrequiredtobemadewithasmallerelectrode.3.Openthegrooveangle.Becarefultoleavetheproperrootfacedimension.4.Featherthestartandstoptoblendsmoothlyintoandoutoftheexistingweld.Removingarootpassbygrindi常见焊接缺陷及检验方法汇总课件ExcessiveConcavityorConvexityDefinition:ConcavityorconvexityofafilletweldwhichexceedsthespecifiedallowablelimitsCause:AmperageandtravelspeedPrevention:Observeproperparametersandtechniques.Repair:Grindofforweldon.Mustblendsmoothlyintothebasemetal.ExcessiveConcavityorConvexiConcavityConcavityConvexityConvexityReinforcementExcessiveInsufficientImpropercontourFaceReinforcementRootReinforcementTheamountofagrooveweldwhichextendsbeyondthesurfaceoftheplateReinforcementExcessiveFaceReExcessiveReinforcementDefinition:Specificallydefinedbythestandard.Typically,Reinforcementshouldbeflushto1.5mm/1/16”(pipe)orflushto3.0mm/1/8”(plateorstructuralshapes).Cause:Travelspeedtooslow,amperagetoolowPrevention:Setamperageandtravelspeedonscrapplate.Repair:Removeexcessivereinforcementandfeathertheweldtoestoasmoothtransitiontothebaseplate.ExcessiveReinforcementDefinitDefinition:Specificallydefinedbythestandard.Typically,Underfillmaybeupto5%ofmetalthicknessnottoexceed0.80mm/1/32”aslongasthethicknessismadeupintheoppositereinforcement.Notappliedtofilletwelds.Cause:Onrootreinforcement-Toolittlefillermetalwillcausethinningofthefillermetal.InOHposition,toohotortoowidewillcausedroopingoftheopenrootpuddle.Prevention:Useproperweldingtechnique.Usebackingorconsumableinserts.Usebackweldorbacking.Repair:Possiblysimplyincreasethefacereinforcement.Ifbackweldingisnotpossible,mustremoveandreweld.InsufficientReinforcementDefinition:SpecificallydefinDefinition:Whentheweldexhibitslessthana1350transitionangleattheweldtoe.Cause:PoorweldingtechniquePrevention:Usepropertechniques.Aweaveorwhipmotioncanofteneliminatetheproblem.Repair:Theweldfacemustbefeatheredintothebaseplate.1350ImproperWeldContourDefinition:WhentheweldexhiOverlapDefinition:WhenthefaceoftheweldextendsbeyondthetoeoftheweldCause:Improperweldingtechnique.Typically,electrodeanglesandtravelspeed.Prevention:Overlapisacontourproblem.Properweldingtechniquewillpreventthisproblem.Repair:Overlapmustberemovedtoblendsmoothlyintothebasemetal.Becarefulofdeepgrindmarksthatruntransversetotheload.Alsobecarefuloffusiondiscontinuitieshiddenbygrinding.UseNDTtobesure.OverlapDefinition:WhenthefaOverlapOverlapismeasuredwithasquareedgesuchasa152.4mm/6”rule.Noamountofoverlapistypicallyallowed.Amountofoverlapnotdeterminedbycodes.OverlapOverlapismeasuredwitBurn-through(non-standard)Definition:Whenanundesirableopenholehasbeencompletelymeltedthroughthebasemetal.Theholemayormaynotbeleftopen.Cause:Excessiveheatinput.Prevention:Reduceheatinputbyincreasingtravelspeed,useofaheatsink,orbyreducingweldingparameters.Repair:Willbedefinedbystandards.Fillingmaysuffice.Otherwise,removalandreweldingmayberequired.Somestandardsmayrequirespecialfillermetaland/orPWHT.Burn-through(non-standard)DefIncompleteorInsufficientPenetrationDefinition:WhentheweldmetaldoesnotextendtotherequireddepthintothejointrootCause:Lowamperage,lowpreheat,tightrootopening,fasttravelspeed,shortarclength.Prevention:Correctthecontributingfactor(s).Repair:Backgougeandbackweldorremoveandreweld.IncompleteorInsufficientPenIncompleteFusionDefinition:Whereweldmetaldoesnotformacohesivebondwiththebasemetal.Cause:Lowamperage,steepelectrodeangles,fasttravelspeed,shortarcgap,lackofpreheat,electrodetoosmall,uncleanbasemetal,arcoffseam.Prevention:Eliminatethepotentialcauses.Repair:removeandreweld,beingcarefultocompletelyremovethedefectivearea.Thisissometimesextremelydifficulttofind.IncompleteFusionDefinition:WArcStrikeDefinition:Alocalizedcoalescenceoutsidetheweldzone.Inlaymenslanguage.Anareawhereanelectricarcscarredthebasemetalcausedbyelectrodearcorelectriccablebeingpulledacrossbasemetal.Cause:CarelessnessPrevention:Indifficultareas,adjacentareascanbeprotectedusingfireblankets.Repair:Whereapplicable,arcstrikesmustbegroundsmoothandtestedforcracks.Iffound,theymustberemoveandrepairedusingaqualifiedrepairprocedureandinspectedasanyotherweld.ArcStrikeDefinition:AlocaliInclusionsSlagWagontrackslinesofslagalongoneorbothsidesofbevelTungsten

InclusionsSlagDefinition:SlagentrappedwithintheweldCause:Lowamperage,impropertechnique,Tryingtoweldinanareathatistootight.SlowtravelinVerticalDownornotpositioningelectrodecorrectlyineitherupordownhandpositions.Prevention:Increaseamperageorpreheat,grindouttightareastogainaccesstobottomofjoint,positionelectrodecorrectly.Repair:Removebygrinding.Reweld.SlagInclusionDefinition:SlagentrappedwitDefinition:Slangtermforagrooveleftatthetoeofarootpasswhichbecomesfilledwithslagandistrappedintheweld.Cause:Thecontouroftherootpassistoohigh,ortheweldtoeisnotbondedtothebasemetalPrevention:Usepropertechniquetodeposittheweldroot.Repair:Bestrepairedbeforeapplyingthehotpass.Carefullygrindtherootpassfaceflat.becarefulnottogougeotherareasontheweldment.WagonTracks(non-standard)Definition:SlangtermforagDefinition:Atungstenparticleembeddedinaweld.(TypicallyGTAWonly)Cause:Tungstenelectrodetoosmall,amperagetoohigh,ACbalanceon+,Upslopetoohigh,electrodetipnotproperlyground,electrodedippedintotheweldpoolortouchedwiththefillrod,electrodesplit.Prevention:EliminatethecauseRepair:GrindoutandreweldTungste