焊趾TIG重熔层激冷处理工艺研究

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1、大连交通大学硕士学位论文焊趾TIG重熔层激冷处理工艺研究姓名：郭常红申请学位级别：硕士专业：材料工程指导教师：史春元;孟立春20081214大连交通大学。l：群硕十学位论文AbstractWiththeprogressofscienceandtechnology．China'srailwayhasenteredtheeraofhigh。speedrailway．Duringthehigh—speedtraveling，theweldedframeworkofbogieisbeatingstrongvibrationandimpactloading．Theanti-fatigueprope

2、rtiesanditsreliabilitiesofthemmleworkwinafrectthesafetyoftraintravel．Therefore，itisverynecessarytostudyin．depththepostweldtreatmenttechnologytotheframework．improvethefatiguestrengthofweldedjointsofUndernomalcircumstances，theweldrootiSnolongertheweakparteasytotormfatiguecrack．buttheweldtoebecomest

3、hefatiguecrackinitiationsourcefortheweldediointsinfullpenetration．Tothatend，thefeasibilityandeffectivenessoftheintensecoolingtechnologyafterTIGdressingintheweldtoewasinvestigatedtoimprovethefatiguestrengthoftheioints．Comparedexperimentsweremadeonthemechanicalproperties，especiallythefatiguestren础o

4、ftheweldedjointsfortheweldtoeinastateofaswelded，TIGdressedandintensecooledtreatmentafterTIGdressingSOaStostudytheinfluencetheintensecoolingtreatmentontheweldingresidualstressstate，fatiguestrength，aswellasthemicrostmcturesandconventionalmechanicalpropertiesofthejoints．Theresearchresultsindicatethr

5、oughtheintensecoolingtreatmentfortheTIGdressedweldtoethattheresidualstressreduceswiththeillcreaseoftemperatureofTIGdressedzone．WhenthetemperatureofTIGdressedregionwasover450℃。theresiduetensilestressesintheweldtoeweretransformedintocompressivestresses，ThemicrostructureswerefineintheTIG—dressedzone

6、anditsHAZobviouslv。thestrength，plasticityandcompacttoughnessoftheweldedjointsfulfilledtechnologicalrequirements．Atthesametime，thesmoothtransitionformedintheTIG￡Iressedzonesoftheweldtoeusingthisnewpostweldtreatmenttechnology，andthestressconcentrationfactorwasreduced，SOthatthefatiguestrength．oftheJ

7、ointWasincreasedgreatly．Keywords：weldtoeTIGdressing；intensecoolingtechnology；residuestress；fatiguestrength．大连交通大学学位论文独创性声明本人声明所呈交的学位论文是本人在导师指导下进行的研究工作及取得的研究成果。尽我所知，除了文中特别加以标注和致谢及参考文献的地方外，论文中不包含他人或集体已经发表或撰写过的研究成果，也不包含为获