管臺(tái)焊接程序課件

管臺(tái)焊接程序管臺(tái)焊接程序管臺(tái)焊接程序ASIAConstructionEngineeringTrainingConferenceFY2007

ASIACONSTRUCTION:

BUILDINGAIRPRODUCTSFUTURESeptember18to22,2006管臺(tái)焊接程序管臺(tái)焊接程序管臺(tái)焊接程序ASIAConstru1管臺(tái)焊接程序課件管臺(tái)焊接程序課件管臺(tái)焊接程序課件管臺(tái)焊接程序課件WeldingsetupReadytoweld:Everyfittingisshapedtofitthepipeandself-aligning

焊接準(zhǔn)備：每一個(gè)管臺(tái)都被加工成適合管道的形狀，以便對(duì)正Theoutletismachine-beveledforquickeasybutt-weldingofbranchpipe

forshoporfieldfabrication

管臺(tái)焊接處被加工成坡口，以適合車間或現(xiàn)場(chǎng)支管快速對(duì)焊WeldingsetupReadytoweld:EWeldingsetupLayout:thetemplateisinsideofthefitting

Cuthole:theholeintherunpipeonreducingsizescanbecutouteitherbeforeorafterthefittingisweldedon.Theholecanbecutwithdrilloraholesaw.Weldingthefittingtorunpippriortocuttingtheholehelpspreventdistortionoftherunpipe

andcanbedonegenerallyonoutletsizeovertwoinches放置模板于管臺(tái)內(nèi)部開孔：變徑管臺(tái)在主觀上的開孔既可以在焊接前也可在焊接后再開。可以用鉆孔，也可用孔據(jù)開孔。先在主管上焊管臺(tái)后開孔可以防止主管扭曲，一般適用大于2英寸的管臺(tái)。WeldingsetupLayout:thetemWeldingsetupSpaceforwelding:Theweldoletisraisedofftherunpipetoestablishproperweldgapbyplacingspacers,e.g.weldingrodsunderthefitting.Thisprovidesauniformweldinggapbetweenthecurvatureoftherunandbaseoffitting

焊接間隙：管臺(tái)焊接前要保證與主管的焊接間隙，例如放一根焊條在管臺(tái)和主管之間。這樣可以保證焊接根部間隙均勻。WeldingsetupSpaceforweldinWeldingsetupTackweld:Thebasejointistackwelded,preferablyatfourpoints,eachhalfwaybetweenthecrotchandskirtsectionsoffitting.Thespacersaretheremoved點(diǎn)焊：根部需要點(diǎn)焊，建議4點(diǎn)，分布在管臺(tái)的肩部，同時(shí)移掉間隙物。WeldingsetupTackweld:ThebWeldingsequenceLongitudinalsection:Widebasesorfootingsatcrotchsectiondistributeinternalandexternalstresses.Gradualchangesofsectioneliminatestressconcentration.Funnelshapedopeningprovidesimprovedflowdirection縱斷面：分叉處存在內(nèi)外應(yīng)力，截面漸變消除了應(yīng)力集中。漏斗狀開口有利于流體流動(dòng)。WeldingsequenceLongitudinalsWeldingsequenceTransversesection:Notetheblendingoftheskirtsectionweldolettotherunpipetoavoidabruptchangeinintersection.Throatofweldatthispointisdesignatedbytheweldingbevel.

橫斷面：管臺(tái)裙叉處和主管處的坡口過渡可以避免交叉點(diǎn)的急劇變化，

WeldingsequenceTransversesecWeldingsequenceStringerbead:Thestringerbeadisappliedcompletelyaroundthebaseofthefitting.Theestablishedweldgapassuresfullpenetration

線型焊道：線型焊道緊緊環(huán)繞管臺(tái)焊接，焊道間隙可以保證完全焊透。

WeldingsequenceStringerbead:WeldingsequenceReinforcingbeads:Reinforcingweldsshouldbemadeatthecrotchbevelareasofthefittingtoprovidemaximumweldatthecrotchtaperingtominimumattheskirt.Particularareshouldbetakentoweldonlythebevelportionofthefitting.Thiseliminatestheunnecessaryuseofcontinuouspassesandpreventstheerroneouspracticeofweldinguptotheribontheskirtportionoffitting.Acontinuouscoverbeadshouldbeaddedtofillthebevelandprovideasmoothtaperedweld.加強(qiáng)焊道：加強(qiáng)焊道應(yīng)該在管臺(tái)分叉處坡口進(jìn)行最大焊接，而在裙尖處進(jìn)行最小焊接，特別是焊接坡口部分。這就是說可以減少一些連續(xù)焊接，防止裙尖處的過渡焊接。連續(xù)的焊接應(yīng)填滿坡口，然后漸縮到裙尖處。WeldingsequenceReinforcingbeWeldingsequenceWeldingsequenceEspeciallynoteWhenusingthechartsinMSSSP-97whenthepipewallscheduleactuallybeingusedisheavierthanlistedinthechartyouneedtousethenexthigherchartdimensions.ThisisbasedononTable1andnote(a)wheresinceourrunpipescheduleisSch80(wallthickness=0.938")andnotXS(wallthickness=0.500")youneedtousetheSCH160classfittingsanddimensionswhichmeansweneedtouse

the

105mmdimension.PurchaseandInspectionmaterialsshouldknowthisprinciple.當(dāng)用MSSSP-97查支管道壁厚時(shí)，表中壁厚應(yīng)該采用高一級(jí)的尺寸。例如：當(dāng)我們知道主管壁厚是Sch80，我們應(yīng)該采用SCH160class的管臺(tái)尺寸，見表。所以采購和檢查時(shí)應(yīng)知道這個(gè)道理。EspeciallynoteEspeciallynotesMultipleoutletheadersrequiringallfullsizeopeningsaresubjecttodistortionbecauseofthelargenumberofholesthathavetobecutincloseproximitytooneanother.Toeliminatethepossibilityofdistortionoccurringwhenusingweldoletsinthistypeofinstallationwerecommendthatastrapbeleftinthecenterofthehole,bycuttingouttwohalfmoonsection(asshowninsketch).Thisstrapactsasasupportuntilaftertheweldolethasbeeninstalledandisthencutout多管臺(tái)的主管，需要開孔的話，由于相距太近，開孔焊接易引起變形。為減少扭曲變形我們推薦在孔中心預(yù)留一塊不切割，

先切割2個(gè)半月狀，然后焊接。而中心這一塊可以防止焊接變形，等完全焊接完成，用曲線據(jù)切除最后這一塊。EspeciallynotesMultipleoutleEspeciallynoteWeldoletweldingoftenoccurredissue:non-penetrationFor4"andabove,itcouldbeweldedatbothside,eventhereissomedifficultywithbackgougingandbackweldingButfor3"andblower,itisnotaccessiblewithbackgougingandbackwelding,thereasonis1)Thetorchsizeweldingatbacksideisimpossibleaccess,andsometimesthetorchcouldnotaccessthebevelwellatsomeangle.2)TheIDofweldoletandopeninginrunpipehassomedeviation.3)Thebevelcurveofweldoletdonotfitpipewell.Oncefoundnonpenetration,needtocuttingofftheweldolet,rewelditfromtherunpipetoachievepenetrationascouldaspossible.1~2mmnon-penetrationisacceptable.Ifmorethan2mmnon-penetration,backsideneedbewelded.

管臺(tái)焊接常出現(xiàn)未焊透問題：大于等于4寸的管臺(tái)，可以從內(nèi)外兩邊焊，雖然有時(shí)內(nèi)部清根焊接有點(diǎn)困難

3寸及3寸以下管臺(tái)，內(nèi)部無法清根和焊接的原因如下

1）焊把尺寸大不易接近內(nèi)部，有時(shí)角度不好而未焊透

2）管臺(tái)內(nèi)經(jīng)合開孔又偏差

3）管臺(tái)坡口曲線與管道不匹配3寸及3寸以下管臺(tái)一旦發(fā)現(xiàn)未焊透，需要割掉管臺(tái)重新焊接或從主管道內(nèi)部焊接。1~2mm未焊透可接受，大于2mm未焊透背面要焊接EspeciallynoteWeldoletweldinSitephoto

WeldoletreceiveandinspectionSitephoto

WeldoletreceiveaSite