摘要
本课题作为X80钢焊接性课题研究的初始工作，主要目的是研究X80钢的焊接性及在焊接过程中产生的冷裂纹的问题，为现场焊接时提供工艺参数的依据。通过选择合适的焊接方法以及改进焊接工艺以提高热影响区的韧性，实现焊缝金属的纯净化与晶粒细化进行深入分析。
本论文采用三种焊接工艺方案：分别使用焊条电弧焊、焊条电弧焊+自保护药芯焊丝半自动焊和全自保护药芯焊丝半自动焊三种方法。工艺一根焊采用BOHLERE9010焊条的焊条电弧焊，采用E9018(BOHLER)-G焊条进行填充焊和盖面焊；工艺二根焊采用E9010(BOHLER)焊条的自保护药芯焊丝半自动焊，采用81N2(HOBART)焊丝进行填充焊和盖面焊均；工艺三采用Metalloy71焊丝打底，JC-29Nil焊丝填充、盖面。
试验结果和分析研究表明：工艺方案三线能量平均11.02KJ/cm，虽然线能量比较小，但焊缝是采用多道薄层的焊接方法，可以得到较好的冲击韧性为165.67J。
利用金相分析方法判断材料的微观形貌，可知三种焊接工艺金相试样的焊缝组织都是由细小针状铁素体和粒状贝氏体构成的复合组织。工艺三的焊缝针状铁素体含量高这样使得接头有很好的力学性能，热影响区晶粒最细小，细小的晶粒可以有效提高强度同时，通过晶界的增多，有效阻止裂纹扩展，提高韧性，还有当X80管线钢中针状铁素体的比例增多时，材料将获得高的夏比冲击韧性。
通过试验观察焊接工艺对焊缝的金相组织及及焊口力学性能的影响，是用焊接工艺三参数，更有利于X80钢焊接在实践中的推广。
关键词：X80管线钢；线能量；工艺参数；组织分析；力学性能
Abstract
InitialworkforthisprojectasX80steelweldingresearch,themainpurposeistoissueweldabilityandproducecoldcrackingduringweldingofX80steelresearch,provideweldingprocessparametersbasedonthescene.Byselectingasuitableweldingmethodandweldingprocessimprovementstoincreasethe
toughnessoftheheataffectedzone,toachievepureofweldmetalandgrainrefinementforfurtheranalysis.
Thispaperusesthreeweldingtechnologyprogram:theweldingarcwelding,SMAW+self-shieldedfluxcoredwiresemi-automaticweldingandfullself-shieldedfluxcoredwiresemi-automaticwelding.
SMAWprocessusingamaterialusedBOHLERE9010electrodes,fillerpassesandcappingareusedE9018(BOHLER)aGelectrode;crafttwosemiautomaticweldingwithself-shieldedfluxcoredweldingrootusingE9010(BOHLER)welding,solderingandfillingcappingareused81N2(HOBART)wire;threeadoptedMetalloy71wirebottomingprocess,JCa29Nilwirefilling,capping.
Testresultsandanalysisshowedthat:three-wireenergytechnologyprogramaverage11.02KJ/cm,althoughthelineenergyisrelativelysmall,butisamulti-channelthinseamweldingmethod,youcangetabetterimpacttoughness165.67J.
Usingopticalanalysismethodtodeterminemicrostructureofmaterials,wecanseethreetypesofcompositetissueweldweldingprocessmetallurgicalsamplesarecomprisedoffineacicularferriteandgranularbainite.Acicularferritecontentofweldprocessthreehighsuchthatthejointhasgoodmechanicalproperties,heat-affectedzonegrainfinest,finegrainscanimprovethestrengthatthesametime,theincreaseingrainboundary,effectivelypreventcrackpropagationimprovethetoughness,aswellaswhentheincreaseintheproportionofX80pipelinesteelacicularferritematerialwillobtainhighCharpyimpacttoughness.
Observetheeffectoftheweldingprocessbytestweldandweldmicrostructureandmechanical
properties,weldingprocesswiththreeparameters,ismoreconducivetothepromotionofX80steelweldedinpractice.
Keywords:X80pipelinesteel;linearenergy;processparameters;organizationalanalysis;mechanicalproperties
目录
摘要................................................................................................................................................IABSTRACT......................................................................................................................................II
第1章绪论...................................................................................................................................1
1.1油气输送管线钢的应用..........................................................................................................1
1.1.1国内自主研发X70管线用钢..........................................................................................1
1.1.2X80及更高钢级的管线钢的自主研发.............................................................................2
1.2油气输送管线钢的焊接..........................................................................................................2
1.2.1管线钢的焊接方法...........................................................................................................2
1.2.2管线钢焊接所遇到的问题...............................................................................................2
1.2.3管线钢的裂纹敏感性研究方法.......................................................................................4
1.3油气输送管道焊接工艺..........................................................................................................5
1.3.1国外长输管道焊接现状...................................................................................................5
1.3.2我国长输管道焊接现状...................................................................................................6
1.4本文研究的主要内容..............................................................................................................7
第2章试验材料及焊接工艺........................................................................................................8
2.1试验选用的材料.....................................................................................................................8
2.1.1钢管..................................................................................................................................8
2.1.2焊材..................................................................................................................................9
2.2X80碳当量分析....................................................................................................................10
2.3X80焊接冷裂纹....................................................................................................................11
2.3.1控制氢源........................................................................................................................11
2.3.2控制应力........................................................................................................................11
2.4焊接工艺设计.......................................................................................................................11
2.4.1工艺方案一....................................................................................................................12
2.4.2工艺方案二....................................................................................................................13
2.4.3工艺方案三....................................................................................................................13
2.5焊后检测...............................................................................................................................14
2.6焊接操作工艺性能分析........................................................................................................14
2.7环焊缝焊接头力学性能........................................................................................................15
2.7.1拉伸性能测试方法.........................................................................................................15
2.7.2弯曲性能试验方法及要求.............................................................................................15
2.8冲击性能检测.......................................................................................................................16
第3章不同焊接工艺对环焊缝焊接头力学性能影响................................................................17
3.1拉伸性能测试结果分析........................................................................................................17
3.2弯曲性能试验结果分析........................................................................................................18
3.3冲击性能检测分析................................................................................................................19
第4章不同焊接工艺对X80管线钢焊接接头金相组织影响....................................................22
4.1X80管线钢金相观察及分析.................................................................................................22
4.1.1试验目的........................................................................................................................22
4.1.2金相观察........................................................................................................................22
4.2冲击试验断口扫描分析........................................................................................................26
4.2.1断口微观形貌................................................................................................................26
4.2.2断口形貌分析................................................................................................................28
第5章结论.................................................................................................................................29