1管台焊接程序Stillwatersrundeep.流静水深流静水深,人静心深人静心深Wherethereislife,thereishope。有生命必有希望。有生命必有希望ASIAConstructionEngineeringTrainingConferenceFY2007ASIA CONSTRUCTION:BUILDING AIR PRODUCTS FUTURESeptember18to22,20063Weldolet welding techniquelWeldolet焊接管台lWeldingsetup管台焊接的准备lWeldoletweldingsequence管台焊接次序lEspeciallynote注意事项lSitephotos施工照片ASIA CONSTRUCTION:BUILDING AIR PRODUCTS FUTURE4Weldolet5Welding set uplReady to weld: Every fitting is shaped to fit the pipe and self-aligning 焊接准备：每一个管台都被加工成适合管道的形状，以便对正焊接准备：每一个管台都被加工成适合管道的形状，以便对正lThe outlet is machine-beveled for quick easy butt-welding of branch pipe for shop or field fabrication管台焊接处被加工成坡口，管台焊接处被加工成坡口， 以适合车间或现场支管快速对焊以适合车间或现场支管快速对焊6Welding set uplLay out: the template is inside of the fittingCut hole: the hole in the run pipe on reducing sizes can be cut out either before or after the fitting is welded on. The hole can be cut with drill or a hole saw. Welding the fitting to run pip prior to cutting the hole helps prevent distortion of the run pipe and can be done generally on outlet size over two inches 放置模板于管台内部放置模板于管台内部 开孔：变径管台在主观上的开孔既可以在焊接前也可在焊接后再开。开孔：变径管台在主观上的开孔既可以在焊接前也可在焊接后再开。可以用钻孔，也可用孔据开孔。先在主管上焊管台后开孔可以防止可以用钻孔，也可用孔据开孔。先在主管上焊管台后开孔可以防止主管扭曲，主管扭曲， 一般适用大于一般适用大于2英寸的管台。英寸的管台。7Welding set uplSpaceforwelding:Theweldoletisraisedofftherunpipetoestablishproperweldgapbyplacingspacers,e.g.weldingrodsunderthefitting.Thisprovidesauniformweldinggapbetweenthecurvatureoftherunandbaseoffitting焊接间隙：管台焊接前要保证与主管的焊接间隙，例如放一根焊条在管台和主管之间。这样可以保证焊接根部间隙均匀。8Welding set uplTackweld:Thebasejointistackwelded,preferablyatfourpoints,eachhalfwaybetweenthecrotchandskirtsectionsoffitting.Thespacersaretheremoved点焊：根部需要点焊，建议4点，分布在管台的肩部，同时移掉间隙物。9Welding sequencelLongitudinalsection:Widebasesorfootingsatcrotchsectiondistributeinternalandexternalstresses.Gradualchangesofsectioneliminatestressconcentration.Funnelshapedopeningprovidesimprovedflowdirection纵断面：分叉处存在内外应力，截面渐变消除了应力集中。漏斗状开口有利于流体流动。10Welding sequencelTransversesection:Notetheblendingoftheskirtsectionweldolettotherunpipetoavoidabruptchangeinintersection.Throatofweldatthispointisdesignatedbytheweldingbevel.横断面：管台裙叉处和主管处的坡口过渡可以避免交叉点的急剧变化，11Welding sequencelStringerbead:Thestringerbeadisappliedcompletelyaroundthebaseofthefitting.Theestablishedweldgapassuresfullpenetration线型焊道：线型焊道紧紧环绕管台焊接，焊道间隙可以保证完全焊透。12Welding sequencelReinforcingbeads:Reinforcingweldsshouldbemadeatthecrotchbevelareasofthefittingtoprovidemaximumweldatthecrotchtaperingtominimumattheskirt.Particularareshouldbetakentoweldonlythebevelportionofthefitting.Thiseliminatestheunnecessaryuseofcontinuouspassesandpreventstheerroneouspracticeofweldinguptotheribontheskirtportionoffitting.Acontinuouscoverbeadshouldbeaddedtofillthebevelandprovideasmoothtaperedweld.加强焊道：加强焊道应该在管台分叉处坡口进行最大焊接，而在裙尖处进行最小焊接，特别是焊接坡口部分。这就是说可以减少一些连续焊接，防止裙尖处的过渡焊接。连续的焊接应填满坡口，然后渐缩到裙尖处。13Welding sequence14Especially notelWhenusingthechartsinMSSSP-97whenthepipewallscheduleactuallybeingusedisheavierthanlistedinthechartyouneedtousethenexthigherchartdimensions.ThisisbasedononTable1andnote(a)wheresinceourrunpipescheduleisSch80(wallthickness=0.938)andnotXS(wallthickness=0.500)youneedtousetheSCH160classfittingsanddimensionswhichmeansweneedtousethe105mmdimension.PurchaseandInspectionmaterialsshouldknowthisprinciple.当用MSSSP-97查支管道壁厚时，表中壁厚应该采用高一级的尺寸。例如：当我们知道主管壁厚是Sch80，我们应该采用SCH160class的管台尺寸，见表。所以采购和检查时应知道这个道理。15Especially noteslMultiple outlet headers requiring all full size openings are subject to distortion because of the large number of holes that have to be cut in close proximity to one another. To eliminate the possibility of distortion occurring when using weldolets in this type of installation we recommend that a strap be left in the center of the hole, by cutting out two half moon section (as shown in sketch). This strap acts as a support until after the weldolet has been installed and is then cut out 多管台的主管，多管台的主管， 需要开孔的话，需要开孔的话， 由于相距由于相距 太近，开孔焊接易引起变形。为减少扭曲太近，开孔焊接易引起变形。为减少扭曲 变形我们推荐在孔中心预留一块不切割，变形我们推荐在孔中心预留一块不切割， 先切割先切割2个半月状，然后焊接。个半月状，然后焊接。 而中心而中心 这一块可以防止焊接变形，这一块可以防止焊接变形， 等完全焊接等完全焊接 完成，完成， 用曲线据切除最后这一块。用曲线据切除最后这一块。16Especially notelWeldolet welding often occurred issue : non- penetrationlFor 4 and above, it could be welded at both side, even there is some difficulty with back gouging and back welding lBut for 3 and blower, it is not accessible with back gouging and back welding, the reason is 1) The torch size welding at back side is impossible access, and sometimes the torch could not access the bevel well at some angle. 2) The ID of weldolet and opening in run pipe has some deviation. 3) The bevel curve of weldolet do not fit pipe well.lOnce found non penetration, need to cutting off the weldolet, reweld it from the run pipe to achieve penetration as could as possible. 12 mm non-penetration is acceptable. If more than 2mm non-penetration, back side need be welded. 管台焊接常出现未焊透问题：管台焊接常出现未焊透问题： 大于等于大于等于4寸的管台，可以从内外两边焊，虽然有时寸的管台，可以从内外两边焊，虽然有时 内部清根焊接有点困难内部清根焊接有点困难 3寸及寸及3寸以下管台，寸以下管台， 内部无法清根和焊接的原因如下内部无法清根和焊接的原因如下 1）焊把尺寸大不易接近内部，）焊把尺寸大不易接近内部， 有时角度不好而未焊透有时角度不好而未焊透 2）管台内经合开孔又偏差）管台内经合开孔又偏差 3）管台坡口曲线）管台坡口曲线 与管道不匹配与管道不匹配3寸及寸及3寸以下管台一旦发现未焊透，寸以下管台一旦发现未焊透， 需要割掉管台重新焊接需要割掉管台重新焊接或从主管道内部焊接。或从主管道内部焊接。12 mm未焊透可接受，未焊透可接受， 大于大于2mm未焊透未焊透背面要焊接背面要焊接17Site photoWeldolet receive and inspection18Site photoAlignment and tack weld19Site photoWeldolet welding20Site photo21Site photo22Site photo23Site photo24Site photoThankyoutellmemorewww.airproducts.com