《华中科技大学文华学院毕业设计文献综述及外文文献翻译》

PAGEPAGE10华中科技大学文华学院毕业设计（论文）外文文献翻译（本科学生用）题目：C02激光焊焊接工艺参数的影响学生姓名：程时学号：070304021102学部（系）:机械与电气工程专业年级:2007材料成型及控制工程指导教师：魏华胜职称或学位：教授20年月日外文文献翻译（译成中文1000字左右）：我国压力容器和管道焊接工艺的新发展在我国锅炉、压力容器和管道制造行业中，各大中型企业的焊接机械化和自动化程度相对较高，像哈锅，上锅这样的企业已达到80%以上。不过，在国际上对焊接机械化和自动化作了重新定义。焊接机械化是指焊接机头的运动和焊丝的给送由机械完成，焊接过程中焊头相对于接缝中心位置和焊丝离焊缝表面的距离仍须由焊接操作工监视和手工调整。焊接自动化是指焊接过程自启动至结束全部由焊机的执行自动完成。无需操作工作任何调整，即焊接过程中焊头的位置的修正和各焊接参数的调整是通过焊机的自适应控制系统实现的。而自适应控制系统通常由高灵敏传感器，人工智能软件、信息处理器和快速反应的精密执行机构等组成。按照上述标准来衡量，我国锅炉，压力容器和管道焊接的自动化率是相当低的。极大多数仅实现了焊接生产的机械化。因此，为加速本行业焊接生产现代化的进程，增强企业的核心竞争力，应尽快提高焊接自动化的程度。按照当前中央提出的“以人为本”的理念。焊接自动化具有更深刻的意义。它不仅仅是提高了焊接生产率和稳定了焊接质量，而更重要的是使焊工远离了有害的工作环境，减轻或消除了职业病的危害。以下列举几个在压力容器和管道制造中已得到实际应用现代化自动焊接装备实例。以说明其基本结构和功能以及在焊接生产中所发挥的作用。1厚壁压力容器对接接头的全自动焊接装备德国Babcock-Borsig公司与瑞典ESAB公司合作于1997年开发了一台大型龙门式全自动自适应控制埋弧装备。专用于、厚壁容器筒体纵缝和环缝的焊接。自1998年正式投运至今使用状况良好，为了型厚壁容器对接缝的自动埋弧焊开创了成功的先例。该装备配置了串列电弧双丝埋弧焊焊头，由计算机软件控制的ABW系统（AdaptiveBattWelding）和激光图像传感器。在焊接过程中激光图像传感器连续测定接头的外形尺寸，测量数据通过计算机由智能软件快速处理，并确定所要求的焊接参数和焊头位置。也就是说每焊道的尺寸和焊道的排列是由系统的软件以自适应的方式控制的。系统软件可调整每一填充焊道的4个焊接参数：焊接速度，焊接电流，焊道的排列和各填充层和盖面层的焊道数。因此，该系统可使实时焊接参数自动适应接头整个长度上横截面和几何尺寸的偏差。焊接速度是控制不同区域内的熔敷金属量，而焊接电流是控制焊道的高度和熔敷金属量。焊道的排列是决定每层焊道间的搭接量。每层的焊道数则取决于每层的坡口宽度。该设备的主控制器和监视器以PC机为基础。多年的使用经验表明，该装备不仅大大提高厚壁容器的焊接生产率，而且确保形成无缺陷的厚壁焊缝，同时显著降低了焊工劳动强度，改善了工作环境。2厚壁管件全自动多站焊接装置火力和核电站的主蒸汽管道，其壁厚已超过100mm，焊接工作量相当大，迫切需要实现焊接生产的全自动化，以提高生产率。每个焊接工作站由焊接操作机，翻转机构，滚轮架，夹紧装置和焊接机头及焊接电源等组成。所有的焊接工作站由中央控制器集成控制。适用的管径范围为139~558mm，壁厚18~100mm.管件长度大于1800mm.可全自动焊接直管对接，直管与弯管接头，直管与法兰以及直管与端盖对接接头。焊接方法采用窄坡口热丝TIG焊。在该自适应控制系统中，采用黑白摄像机检测坡口边缘的位置。采用彩色摄像机监控电弧和填充丝的位置。通过检则焊丝加热电流控制填充丝的垂直方向的位置。这种控制方法是利用黑白摄像机的图像，经过计算机图像处理，确定内外边缘的照度差。当焊接条件变化时，系统将自动调整摄相机快门的曝光时间。以达到给定的照度，使焊枪始终保持在焊接开始时调整好的位置。壁厚管件全自动多焊接装置基本上实现了焊接作业无人操作。只需要一名操作人员在主控制室内设置管件的原始条件并在焊接过程中进行监控。这种全自动焊接装置已在日本三菱重工公司投入生产试用。3大直径管对接全位置自TIG焊机大直径管对接的全位置TIG焊是一项难度很大的焊接作业，培养一名技能高度熟练的焊工需要耗费大量的人力和物力，而且产品的焊接质量还取决于焊工自身多年积累的生产经验。为了克服对焊工技能的依赖性，消除人为因素对产品焊接质量的不利影响，产生了开发模拟高级熟练焊工的智能和操作要领的全自动焊管机的想法。该自动焊管机可用于直径165—1000mm，壁厚7.0—35.0mm的不锈钢管环缝的全位置焊，并采用窄间隙填丝TIG焊（单层单道焊工艺）。焊机的自动控制系统采用了视觉和听觉传感器，由计算机程序控制执行机构，模仿熟练焊工的反应和动作。自适应控制和质量监控系统的作用原理为，自适应控制主要是通过视觉传感器实时检测的信息和计算机图像处理，按模糊逻辑规则，实时控制钨极相对于坡口边缘的位置，填充焊丝相对于钨极的位置以及决定焊接熔池尺寸的焊接参数。而焊缝质量的监控系统则按照激光视频传感器，听觉传感器和电流传感器的信息实时修正焊接熔池尺寸，焊道形状，钨极尖端的形状，电弧燃烧的稳定性和焊接电流，以保证焊缝质量的一致性。在自适应控制系统中，安装在焊枪前侧的视觉传感器（摄像机）起主要作用，将所摄取的对接区图像输入到计算机，根据计算机软件图像处理结果，可以定量检测钨极相对于坡口边缘的位置，填充焊丝相对于钨极的横向位移，以及焊接熔池的尺寸及钨极的损耗。激光视频传感器是由摄像机和激光聚光灯组成，安装在焊枪的后侧。所形成的图像可用来测定焊道边缘的润温角，即焊道表面与坡口侧壁之间的角度。控制系统根据这些信息，对焊接参数进行自适应控制。自适应计算方法的工原理如下。焊接过程中，为调整钨极的位置，引用了模糊逻辑理论，即所谓奇数理论。当前节距内钨极位置的修正速度是按所测定的钨极位移量和前一节距内的修正速度计算的，以此来保证修正精度。上述大直径管全自动全位置焊管机已在电站锅炉安装工程中得到实际的应用，取得了令人满意的效果。附注NewdevelopmentsofPressurevesselsandpipinginweldingtechnology

InChina'sboilers,pressurevesselsandpipemanufacturingindustry,themajormediumofweldingrelativelyhighdegreeofmechanizationandautomation,suchasKazakhstanpot,thepotsothattheenterprisehasreached80%.However,intheinternationalweldingmechanizationandautomationwereredefined.Mechanizedweldingistheweldingheadofthemovementandthewire'stogetdonebythemachinery,weldingprocess,weldingheadrelativetothejointcenteroftheweldsurfaceandthedistancefromthewirestillbytheweldingoperatormonitoringandmanualadjustment.Weldingprocess,weldingautomationisallfromthestarttotheendoftheimplementationbythewelderautomatically.Workwithoutanyadjustmentoperation,theweldingprocess,weldingpositionofthefirstamendmentandtheadjustmentofweldingparametersbyadaptivecontrolweldingsystemimplementation.Theadaptivecontrolsystemisusuallyhighlysensitivesensors,artificialintelligencesoftware,informationprocessorsandrapidresponseprecisionactuatorsandothercomponents.Accordancewiththeabovestandards,ourboilers,pressurevesselsandpipeweldingautomationrateisverylow.Onlytorealizethevastmajorityofthemechanizationofweldingproduction.Therefore,toacceleratethemodernizationoftheindustryweldingproductionprocess,enhancetheircorecompetitiveness,assoonaspossibletoimprovethedegreeofweldingautomation.InaccordancewiththecurrentCentralCommitteeofthe"peoplefirst"concept.WeldingAutomationhasamoreprofoundsignificance.Itnotonlyincreasesproductivityandstabilityoftheweldingqualityofweldingand,moreimportantly,thewelderfromharmfulworkenvironment,reduceoreliminateoccupationalhazards.

Thefollowingareafewinthemanufactureofpressurevesselsandpipinghasbeenthepracticalapplicationofmoderninstancesofautomaticweldingequipment.Toillustrateitsbasicstructureandfunctionaswellasinweldingproductionrole.

Athick-walledpressurevesselsfullyautomaticweldingequipment,buttjoints

Babcock-BorsigcompanyinGermanyandSwedencompaniesin1997,ESABhasdevelopedafullyautomaticadaptivecontroloflargegantrysubmergedarcequipment.Dedicated,thick-walledVessellongitudinalseamandgirthweld.Officiallyputintooperationsince1998,hasusesingoodconditionandtypeofthick-walledcontainerfortheautomaticsubmergedarcweldingontheseamstocreateasuccessfulprecedent.

Theequipmentconfigurationoftheserialtwo-wiresubmergedarcweldingarcweldinghead,controlledbythecomputersoftwareABWsystem(AdaptiveBattWelding)andlaserimagesensor.

Laserweldingprocessinacontinuousdeterminationoftheimagesensorconnectordimensions,measurementdatathroughcomputerprocessingbyintelligentsoftwaretoquicklyanddeterminetherequiredweldingparametersandweldingheadposition.Thatisthesizeofeachbeadandbeadarraysystemsoftwareisthewaytoadaptivecontrol.

Systemsoftwaretoadjusteachofthe4fillweldweldingparameters:weldingspeed,weldingcurrent,weldthearrangementandthefillinglevelandcapthenumberofthesurfacelayeroftheweldbead.Therefore,thesystemcanautomaticallyadapttheweldingparametersinrealtimetheentirelengthofthejointcross-sectionandgeometryofthedeviation.Weldingspeedistocontrolthedifferentregionswithinthevolumeofdepositedmetal,andweldingcurrentistocontrolthebeadheightandtheamountofdepositedmetal.Thearrangementistodeterminetheweldbeadbetweeneachofthelapvolume.Thenumberofeachdependsoneachweldgroovewidth.Thedevice'smaincontrollerandthemonitortoPC-based.

Yearsofexperienceshowthattheequipmentnotonlygreatlyincreasedtheproductivityofweldingthick-walledvessels,butalsotoensuretheformationofthickdefect-freeweld,welderwhilesignificantlyreducingthelaborintensityandimprovetheworkingenvironment.

2thick-walledpipeweldingequipmentautomaticmulti-station

Fireandnuclearpowerstationsthemainsteampipe,thewallthicknessmorethan100mm,alargeweldingwork,theurgentneedtoimplementfullyautomatedweldingproduction,toincreaseproductivity.Eachweldingstationbytheweldingoperationmachine,flipinstitutions,rollerframe,clampingdeviceandtheweldingheadandweldingpowersuppliesandothercomponents.Alltheweldingstationbythecentralcontrollerintegratedcontrol.Applicablediameterrange139~558mm,thickness18~100mm.Tubeislongerthan1800mm.Canbefullyautomaticbuttweldstraightpipe,straightpipeandpipefittings,straightpipewiththeflangeandthestraightpipeandcoverbuttjoint.NarrowgrooveweldingusinghotwireTIGwelding.

Intheadaptivecontrolsystem,theuseofblackandwhitecamerasdetectthepositionoftheedgegroove.Colorcameramonitoringbywirearcandfillingtheposition.Checkthewireheatingcurrentthroughthecontrolwirefilledverticalposition.Thiscontrolmethodistheuseofblackandwhitecameraimage,afterimageprocessingtodeterminethedifferencebetweeninsideandoutsidetheedgeoftheillumination.Whentheweldingconditionschange,thesystemwillautomaticallyadjustthecamerashutterexposuretime.Inordertoachieveagivenillumination,sothattheweldingtorchandalwaysmaintainagoodpositiontoadjustthestart.

Automaticmulti-walltubeBasicallyrealizedweldingequipmentweldingoperationunattendedoperation.Onlyoneinthemaincontrolroomoperatortosettheoriginalconditionsandtubeintheweldingprocesstobemonitored.TheautomaticweldingequipmentcompanyinJapan,MitsubishiHeavyIndustriesproductiontrial.

3large-diameterpipefromtheTIGbuttweldinginallposition

Large-diameterpipebuttweldall-positionTIGweldingisaverydifficultjob,trainingahighlyskilledwelderskilltakesalotofmanpowerandmaterialresources,butalsoonthequalityofweldingproductsweldersownproductionexperienceaccumulatedovertheyears.Toovercomethedependenceontheskillsoftheweldertoeliminatethehumanfactorontheadverseeffectsofweldingqualityproducts,resultinginthedevelopmentofintelligentsimulationofhighskilledweldersandoperatingessentialsautomatictubeweldingmachineidea.

Theautomatictubeweldingmachinecanbeusedfordiameter165-1000mm,wallthicknessof7.0-35.0mmstainlesssteelpipegirthoftheall-positionwelding,andusingnarrowgapTIGweldingfillerwire(single-layersingle-passweldingprocess).Weldingmachineautomaticcontrolsystemusesvisualandauditorysensors,actuatorscontrolledbyacomputerprogramtomimicthereactionofskilledweldersandaction.

Adaptivecontrolandtheroleofqualitycontrolsystemstheoryis,adaptivecontrolmainlythroughthevisualsensorinformationinreal-timedetectionandcomputerimageprocessing,accordingtofuzzylogicrules,real-timecontroloftungstenrelativetothebeveledgeofthelocation,relativetothefillerwiretungstenandtodeterminethelocationoftheweldingparametersofweldpoolsize.Theweldqualitymonitoringsysteminaccordancewiththelaservideosensors,audiosensorsandcurrentsensorinformationinrealtimecorrectionoftheweldpoolsize,beadshape,theshapeofthetungstentip,thearcweldingcurrentcombustionstabilityandtoensurethattheweldconsistentquality.

Intheadaptivecontrolsystem,installedinfrontofthevisionsensortorch(camera)toplayamajorroleinthedockingareatotheintakeofimageinputtothecomputer