Q345钢的CO2气体保护焊的工艺研究1

洛阳理工学院毕业设计（论文）IQ345钢的CO2气体保护焊的工艺研究摘要本文以Q345钢的CO2气体保护焊的工艺为例对其进行了分析与研究。Q345钢综合力学性能良好，低温性能亦可，塑性和焊接性良好，用做中低压力容器、油罐、车辆、起重机、矿山机械、电站、桥梁等承受动载荷的结构。热轧或正火状态使用，可用于-40℃以下寒冷地区的各种结构。二氧化碳气体保护焊目前已发展成为一种重要的熔焊方法，具有成本低、效率高、操作灵活等特点。广泛应用于汽车、工程机械、造船业、机车、电梯、锅炉压力容器等制造业，以及各种金属结构和金属加工机械的生产。本文首先分析了Q345钢的焊接性，其次对CO2气体保护焊特点和工艺的进行了分析，从而确定了Q345钢的CO2气体保护焊焊接工艺。通过工艺参数的优化选择，不仅能减少焊接过程中的常见问题，而且有效减少焊接缺陷的出现，并能提高生产效率，节约生产成本。关键词：Q345钢，CO2气体保护焊，工艺，焊接缺陷洛阳理工学院毕业设计（论文）IITECHNOLOGYOFSTUDYQ345STEELBYCO2GASWELDINGPROTECTIONABSTRACTInthispaper,Q345SteelCO2gasshieldedweldingprocessasanexampleofitsanalysisandresearch.GoodmechanicalpropertiesofQ345steel,lowtemperatureperformancecan,plasticandweldingofgood,usedinlowpressurevessels,tanks,vehicles,cranes,miningmachinery,powerplants,bridgesandotherstructurestowithstanddynamicload,mechanicalparts,buildingstructures,Generalmetalstructure,useofhot-rolledornormalizedcondition,thefollowingcanbeusedin-40℃coldregionsofthevariousstructures.Inordertoimproveefficiency,costsavings,andmoreuseofweldingtechnology.Carbondioxidegasweldingprotectionhasgrowntobecomeanimportantbywelding,withlowcost,efficientandflexibleoperatingcharacteristics.Itiswidelyusedinthecarengine,shipbuilding,constructionmachinery.Theboilerpressurevessel,suchasmanufacturing,andallsortsofmetalandmetalprocessingmachineryproduction.ThispaperanalyzestheQ345steelwelding,followedbyCO2gasshieldedweldingonthecharacteristicsandprocessesareanalyzedtodeterminetheQ345steelCO2gasshieldedweldingprocess.Optimizationofprocessingparameters,notonlycanreducetheweldingprocessoffrequentlyaskedquestions,andeffectivelyreducetheappearanceofwelddefects,andcanimproveproductionefficiency,savingproductioncost.KEYWORDS:Q345steel，CO2gasshieldedwelding，technology，defectsofwelding洛阳理工学院毕业设计（论文）III目录摘要………………………………………….………...……………………ⅠABSTRACT……………………………………………………..……………Ⅱ目录......................................................................................................Ⅲ前言……………………………..………………….…………..…................1第1章Q345钢及CO2气体保护焊简介…………………….................31.1Q345钢简介………………………....................................................31.1.1Q345钢的应用与分类……..........................................................31.1.2Q345化学成分及力学性能分析……........................................…31.1.3Q345钢的焊接特点……..........................................................…41.2CO2气体保护焊简介…………………….........................................…41.2.1CO2气体保护焊发展史……………………...............................…51.2.2CO2气体保护焊特点……......................………………..………..61.2.3CO2气体保护焊冶金原理……..................................................…61.2.4CO2气体保护焊的熔滴过渡形式…..............................................7第2章CO2气体保护焊工艺………………..............................………82.1焊前准备..…….......................................………………………………82.1.1坡口设计….........................................................................……82.1.2坡口加工方法与原理…......................................................……92.1.3定位焊缝…….........................................................................…92.2焊接参数的选择……….............................................................……..92.2.1焊丝直径的选择……………................…………………………102.2.2焊接电流的选择………..…...................………………………..102.2.3电弧电压的选择……….………...............………………………112.2.4焊接速度的选择…………..…………..................................…112.2.5焊丝伸出长度的选择….....................................................……112.2.6电流极性的选择……............................................................…122.2.7气体流量的选择…............................................................……12洛阳理工学院毕业设计（论文）IV第3章Q345钢在CO2气体保护焊时常见问题及对策…....….…133.1焊接裂纹..…………………………...................……….…..…….……133.1.1冷裂纹………………………………..................................………133.1.2其它裂纹…………………………….............................…….……143.2气孔……………………...….................................................…..……153.2.1N2气孔…...........................................................................……163.2.2H2气孔…............................................................................……163.2.3CO气孔…...........................................................................……163.3焊接飞溅…......................................................................................173.3.1飞溅产生原因…...............................................................……173.3.2减少飞溅的方法…............................................................……17第4章Q345钢的CO2气体保护焊工艺的确定…......................…204.1矩形管组焊方案的确定……................………….………………204.2焊接工艺…………………..........................................………………204.2.1坡口形式..................................................................................204.2.2定位焊缝….............................................................................214.2.3焊接工艺参数…................................................................…214.2.4焊接顺序…..................................................……....………22结论......................................................................................................23谢辞.................................................................................................24参考文献..........