1、INTRODUCTION.3Joint details .4Joint types .5Electrode positioning angles .6Pipe classification .7Consumption of electrodes .11ASME / EN positions .13THE MANUAL METAL ARCPROCESS.15General information .16Filler materials .17Pipeweld cellulosic electrodes .17Basic electrodes .19Basic electrodes - Techn
2、ical data .20Cellulosic electrodes - Technical dfata.22WELDING TECHNIQUESAND OPERATIVE PRACTICES.25General information .26Pipe welding in vertical down (downhill)with cellulosic electrodes1 - Preparation and tacking .272 - Joint in 5G/PG position .293 - Joint in 6G/H-L045 position .35Welding of pipe
3、s in vertical up (uphill)with mixed cellolosic/basic technique1 - Preparation and tacking .382 - Joint in 5G/PF position .403 - Joint in 2G/PC position .444 - Jioint in 6G/H-L045 position .47DEFECTS: CAUSES AND REMEDIES.49AUTOMATIC PIPE WELDING.53General information .54Filler materials .55Welding te
4、chniques and operational practices .57Examples of WPS .58Comparison between three welding methods.62Defects and remedies .63List of contents12PresentationEvery day countless kilometres of steel pipelines are installedworldwide for the most varied civil and industrial uses.They form real networks com
5、parable to a system of road networks,which, although not so obvious, are definitely much more intricate andcarry fluids that have become essential for us.To comply with technical specifications and fulfil the necessary safetyrequisites, special materials and welding processes which haveevolved with
6、the sector have been developed in recent years.The main welding process used to install the pipelines is manualwelding with coated electrode, which, thanks to its ease andversatility, is still the one most used.However, to limit costs and increase welding productivity, particularlyon long routes, va
7、rious constructors have adopted the semi-automaticor completely automatic welding process with solid wire or wireflux coated with gaseous protection.This handbook describes both methods. Ample space has beendedicated, in particular, to manual welding, with particular reference tothe operative practi
8、ce and quality assessment, due to its considerableuse still today, but not neglecting more modern and productivemethods which will be increasingly used in future.The presumption of this work is to be able to satisfy the mostdemanding technician and welder, but, in particular, to supply eachuser with
9、 useful information and a solid operative basis, as regardsthe processes and filler materials and the welding equipment.标准分享网 w w w .b z f x w .c o m 免费下载INTRODUCTIONButt Joint1. Root gap: separation between the edges to be weldedat the root of the joint2. Root face: surface of the joint preparation
10、perpendicular to the surface of the plate3. Bevel surface: oblique surface of the joint preparation4. Bevel angle: angle between the bevelled surface anda plane perpendicular to the plate5. Included angle: total angle between the two bevelsurfaces6. Seam width: effective width of the joint (distance
11、between the bevels plus depth of penetration).Thewidth of the calking iron seam and groove iron are thesame thing7. Thickness of the plateFillet Joint1. Throat thickness: distance between seam root andsurface measured on the bisector of the angle2. Leg lenght: distance between seam root and edge3. J
12、oint root: point in which the bottom of the seamintersects the surface of the base metal4. Joint edge: junction point between seam surface andbase metal surface5. Joint surface: external surface of the seam6. Fusion depth: depth reached by the fusion bath fromthe surface of the base metal7. Seam wid
13、th: distance between the joint edgesJoint details4标准分享网 w w w .b z f x w .c o m 免费下载Many other variations are possible.51. Butt jointwithout bevel2. Butt jointwith V bevel3. Butt jointwith X bevel4. Butt jointwith unilateralbevel5. Butt jointwith doubleunilateral bevel6. Butt jointwith U bevel7. But
14、t jointwith doubleU bevel8. Butt jointwith J bevel9. Butt jointwith doubleJ bevel10. Fillet joint11. Double fillet jointJoint typesIn this handbook the official AWS method is used todefine the positioning angles of the electrodes (EN added).Two angles are indicated: the feed angle and the workangle.
15、The feed angle is called “TO BE PUSHED” when theelectrode points in the feed direction.The feed angle is called “TO BE PULLED” when theelectrode points in opposite direction to the feed.The work angle is given in relation to a reference planeor work plane.The figures illustrate the definition method
16、 of the angles.Taking the clock face as reference, 1 minute correspondsto 6.WORK PLANEFEEDWELDING AXISFEED PLANEANGLE TO BE PULLEDANGLE TO BE PUSHEDWORK PLANEFEED PLANEANGLE TO BE PUSHEDANGLE TO BE PULLEDFEEDWELDING AXISWORK PLANESYMMETRY AXISSYMMETRY AXISFEED PLANEFEEDANGLE TO BE PUSHEDANGLE TO BE
17、PULLEDElectrode positioning angles6VerticalHorizonal标准分享网 w w w .b z f x w .c o m 免费下载Pipe classificationNon-welded and welded pipes sized in accordance with ANSI B 36.10 and API standards7Prescriptions concerning the results of the traction and bending test for thicknesses 25mm1, and for the hydros
18、tatic test8Designation of the steelsPipe bodyWelding seamPipe(unwelded and welded pipes)HFW, SAW,SAW, COWCOWAlphanumericNumericUnitary yieldingTensileElongation3TensileDiameter ofHydrostaticpointstrength(L0= 5,65S0strengththe spindletestfor bendingR10,5RmR10,5/Rm2ARmtest4(see 8.2.3.5)(see 8.2.3.8)MP
19、aMPa%MPamin.max.min.min.L245NB1.0457from 245 to 4404150,80223 TL245MB1.04180,85L290NB1.0484from 290 to 4404150,80213 TL290MB1.04290,85L360NB1.05820,85L360QB1.8948from 360 to 5104150,88204 TL360MB1.05780,85L415NB1.89720,85L415QB1.8947from 415 to 5654200,88185 TL415MB1.89730,85L450QB1.8952from 450 to
20、5705350,90186 TL450MB1.89750,87L485QB1.8955from 485 to 6055700,90186 TL485MB1.89770,90L555QB1.8957from 555 to 6756250,90186 TL555MB1.89780,901The mechanical features of pipes with greater thickness values of up to 40mm must be agreed.2The values of the ratio between the unitary yield point and the t
21、ensile strength are applied for the “pipe”product.They cannot be requested for thestarting material.3These values are applied for transversal samples withdrawn from the body of the pipe.If longitudinal samples are tested, the elongation valuesmust be increased by 2 units.4T = prescribed pipe thickne
22、ss.The same va-lues as the pipebody are ap-plied.Each pipe musttake the testwithout showinglosses or visibledeformations标准分享网 w w w .b z f x w .c o m 免费下载Outside diameters and preferential thicknesses (indicated in the framed zone of the table,including the frame itself)OutsideThicknessdiametermmmm2
23、,32,62,93,23,644,3555,66,37,188,8101112,5 14,21617,52022,225283032364033,742,448,360,388,9114,3168,3219,1273323,9355,6406,44575085596106607117628138649141 0161 0671 1181 1681 2191 3211 4221 5241 626910Mechanical features / Chemical compositions (A.P.I. steels)A.P.I.Mechanical propr. N/mm2Chemical co
24、mposition %CarboniumspecificationQualityYieldingTensileCarbonManganese(max)pointstrength(max)(max)equivalent标准分享网 w w w .b z f x w .c o m 免费下载11Consumption of electrodesPipeweld electrodes consumption (kg) in downhill vertical12Pipeweld electrodes consumption (kg) in uphill verticalNote: for pipes o
25、f less than 152mm (6”) diameter, with wall thickness up to 6.4mm, Pipeweld 6010, diameter 2.5mm, may be used for the first bead.Approximate weight of Pipeweld electrodes 3.25 approx. 28 grams 4.25 approx. 40 grams 5.25 approx. 62 grams标准分享网 w w w .b z f x w .c o m 免费下载131G/1F (PA)2G (PC)3G/3F1F (PA)
26、2F (PB)3G/3F4G(PE)5G6GPG - DOWNHILLPF - UPHILLPG - DOWNHILLPF - UPHILLPG - DOWNHILLPF - UPHILL(H-LO45)ASME/EN positions标准分享网 w w w .b z f x w .c o m 免费下载THE MANUAL METAL ARCPROCESS16General informationThe main welding process used to weld pipelines is theMMA method, manual welding with coated electr
27、odes.There are many reasons for this choice.The first is themost obvious: the manual electrode is the first productinvented that is suitable for arc welding.However, still today, when more sophisticated materialsand more productive and less expensive techniques areat the users disposal, MMA welding
28、remains a favouredprocess to weld pipes. Its easy use, capacity to reachpositions of difficult accessibility, the simplicity of thenecessary generators (or the fact of being able to usemotor generators; network power is not always availableon installation sites), the fact that protective gases(diffi
29、cult to find in certain countries, in particular thirdworld countries), necessary in welding with solid or coredwires, are not required, all these and others are thereasons for this choice.Some classes of cellulosic and basic electrodes havebeen specially designed to meet the requirements of thegrad
30、e of steel used to manufacture the pipeline and thesafety specifications laid down by standards, but also toequip the user i.e. welders with versatile products createdfor this specific purpose.标准分享网 w w w .b z f x w .c o m 免费下载Care and storage of cellulosic electrodesCellulosic electrodes need a def
31、inite amount of moisture,normally between 3% and 9%, to give satisfactoryoperation. Over drying this type of electrode will lead tocharring of the organic material within the coating.Thiscan give un-satisfactory welding performance, loss of arcvoltage and weld metal porosity.These types ofelectrodes
32、 should NOT be re-dried.Tin-Pac for transport and stockage in heavyenvironmentsThe ESAB range of consumables for pipeline weldinghas been developed to match the steel qualities and thedemands from the pipeline industry for reliable, easy to17OK PIPEWELD CELLULOSICELECTRODESOK Pipeweld electrodes hav
33、e always been a safe andproductive solution in the welding of pipelines.Features High Cellulose content in the electrode provides anintense arc good penetration in all positions. High Cellulose content gives small slag covering of theweld bead, although it is easily re-melted it is advisableto remov
34、e before welding the next bead. The thin coating combined with the penetrating arcenables a smaller root gap to be utilised and thecomplete joint requires less weld metal to bedeposited. The rapid solidification of the weld metal allows truly allpositional weldingRecommended current ranges for the d
35、ifferentwelding positions.Welding equipmentThe welding generators that can be used with OKPipeweld need to have a relatively high open circuitvoltage (OCV 65V) and good dynamic characteristics.This prevents the arc snapping out during the weldingoperation.Filler materialsuse highly productive consum
36、ables. Our resources inresearch and development around the world have madeit possible not only to meet the demands of today butalso to foresee the needs for tomorrow. Cellulosicelectrodes from ESAB are used for root pass, filling andcapping on a wide range of steels used in the pipelineindustry and
37、pipework production.ESAB Electrode Choice for each Bead Position18Pipe steelRoot orHot passHot fillFillerCappingand gradestringerpasses5L, A255L, 5LS, A5L, 5LS, B5LS, 5LX425LS, 5LX465LS, 5LX52 5LX56 5LX60 5LX65 5LX70 = Pipeweld 6010 Plus = Pipeweld 7010 = Pipeweld 8010DOWNHILL VERTICALPOSITIONUPHILL
38、 VERTICALPOSITIONFINAL BEADROOT PASSFILLING BEAD1,2 1,62,5 3,2标准分享网 w w w .b z f x w .c o m 免费下载19BASIC ELECTRODESWhen the pipeline steel has a strength higher than X70the need of preheat and post weld heat treatmentbecomes more stringent and the choice of using basicelectrodes offers advantages.The
39、 reason is, of coursethe high amount of hydrogen in the weld metal fromcellulosic electrodes.The hydrogen is a greater risk forcracks in high strength material, because of theincreased sensitivity to hardening in these steels.The properties of the basic electrodes also mean muchbetter impact propert
40、ies at low temperatures.The disadvantage with basic electrodes welded verticallyup is the low current that has to be used resulting in lowproductivity.This can be avoided by using basic electrodes developedspecially for welding of pipelines in the vertical-downposition.These electrodes contain iron
41、powder in thecoating and therefore have higher productivity thancellulose electrodes since they also can be welded athigher currents than cellulose electrodes.Productivity is 25-30% higher than for celluloseelectrodes and 40-50% higher than for basic electrodesin vertically up welding.In the root, t
42、he penetration and force from a celluloseelectrode is however the most productive process sincethey can manage a small root-opening with high currentresulting in fast progression. A basic electrode can beused also for the root but requirements on alignment willbe higher because of the less forceful
43、arc.The best procedure for welding high strength pipelines istherefore to use cellulose electrodes for the root pass andbasic vertical down electrodes for filling and capping passes.The higher quality of the basic weld metal isadvantageous when a pipeline is exposed to stress.When, during its route,
44、 an underground pipe (mediumand large diameters) crosses roads and railways, whengreater static and dynamic stress exists for externalreasons or when the pipes of medium and smalldiameter are submitted to high temperatures, strongpressure and vibration (heating plants, refineries etc.), itis normall
45、y preferred to carry out the first bead withPipeweld and the filling with a basic electrode.With this, the complete penetration that only Pipeweldcan guarantee and the maximum tenacity of the joint dueto the electrode with basic coating are obtained.Some mechanical characteristics, in particular the
46、 valuesof toughness and strength, were improved.OK 48.00 is classified E 7018-1; this means that itsupplies resiliency values of over 27j at 46C, thanks tothe purity of its components, in an even better developedformula.It can be used to weld steels with high values ofequivalent carbon and/or high e
47、lastic limit thanks to thelaying which guarantees values of diffusible hydrogen of 5 ml/100 gr. and consequently makes the risk of coldcracks practically non-existent, also permitting areduction of the pre-heating temperature required for thebasic electrodes. In addition to these metallurgical andpr
48、oductive aspects that are important for the constructor,there is improved welding capacity.The excellent startingand restarting, the constant and regular fusion and thefine aspect of the weld seam in all positions arecharacteristics of fundamental importance for the welderand guarantee a high produc
49、tivity.The VacPac boxing (plastic inner box with Vac Packedaluminium foil hermetically sealed) ensures thesecharacteristics, over a long time and allows the productto be used without redrying.A.P.I.QualitySuggested ElectrodeSpecificationFirst rootFilling5LA 25Pipeweld 6010OK 48.005L 5LSAPipeweld 601
50、0OK 48.005L 5LSBPipeweld 6010 OK 48.005LXX42Pipeweld 6010OK 48.005LXX46Pipeweld 6010 OK 48.005LXX52Pipeweld 6010 OK 48.005LXX56Pipeweld 6010 OK 48.005LXX60Pipeweld 6010 OK 48.005LXX65Pipeweld 6010 OK 74.705LXX70Pipeweld 6010 OK 74.7020Basic electrodes for steels with mediumand high yield strengthEle
