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ID:32691442
大小:1.38 MB
页数:8页
时间:2019-02-14
《对于热影响区元素晶界偏聚对焊接构件低周疲劳性能的影响》由会员上传分享,免费在线阅读,更多相关内容在工程资料-天天文库。
1、学兔兔www.xuetutu.com第51卷第14期机械工程学报vo1.51N0.142015年7月JOURNALOFMECHANICALENGINEERINGJu1.2Ol5DoI:10.3901/JM[E.2015.14.078热影响区元素晶界偏聚对焊接构件低周疲劳性能的影响木汤之南2蔡志鹏,2吴健栋2(1.清华大学机械工程系北京100084;2.清华大学先进成形制造教育部重点实验室北京100084)摘要:对25Cr2Ni2MoV低压转子钢焊接模拟件进行低周疲劳性能试验,测得焊接接头应变与疲劳寿命关系式,对比分析接头不同区域低周疲劳性能,确定热影响区
2、是接头低周疲劳性能的薄弱环节。进行焊接接头硬度分布测定、疲劳裂纹扩展路径金相分析以及热影响区原奥氏体晶界元素偏聚行为俄歇分析等一系列试验。结果表明,焊接接头热影响区存在大硬度梯度的软硬界面,在疲劳载荷作用下形成应变集中,导致焊接构件低周疲劳性能弱化;在热影响区扩展过程中,疲劳裂纹遇到原奥氏体晶界往往会沿着晶界发生偏折,并在晶界上形成一定程度的割裂;俄歇分析表明热影响区原奥氏体晶界存在明显的杂质元素S和合金元素Cr的偏聚,其共同作用致使该区抗疲劳裂纹扩展性能弱化,从而降低整个焊接构件的低周疲劳性能。关键词:低周疲劳;焊接构件;热影响区;晶界偏聚;硬度分布中
3、图分类号:TG457InfluenceofElementSegregationatGrainBoundaryofHeatAffectedZoneonLow-cycleFatiguePropertyofWeldmentTANGZhinan,CAIZhipeng,WUJiandong,(1.DepartmentofMechanicalEngineering,TsinghuaUniversity,Beijing100084;2.KeyLaboratoryforAdvancedMaterialsProcessingTechnologyofMinistryofEd
4、ucation,TsinghuaUniversity,Beijing100084)Abstract:Alow-cyclefatiguepropertytestisconductedonthetestpieceofweldedrotormadeby25Cr2Ni2MoVmateria1.Therelationofstrainandfatiguelifeismeas~edandthelow-cyclefatiguepropertiesofdiferentjointzonesarecontrastinglyresearched.Theheatafectedzo
5、neistherelativelyweakpartofweldedjointonlow-cyclefatigueproperty.Researchesofmarxhardnessdistributionofweldedjoint,fatiguecrackpropagationpathandaugerelectroncomponentanalysisofelementsegregationatoriginalaustenitegrainboundaryofheatafectedzoneareconducted.Theresultsshowthatsoftz
6、oneandinterfaceofhardandsoftappearintheheatafectedzone,whichmakesitsuferbigstrainconcentrationandreducedlow—cyclefatiguepropertyunderfatigueload.Inheatafectedzone,thefatiguecrackpropagationpathislikelytodeflectalongtheoriginalaustenitegrainboundaryandseparatetheboundarytosomeexte
7、nt.ThroughAESanalysis,obviouselementsegregationofSandCrarefoundattheoriginalaustenitegrainboundaryofheatafectedzone,whichweakenstheresistanceoffatiguecrackpropagationofthiszoneanddegradesthelow-cyclefatiguepropertyofthewholeweldment.Keywords:low-cyclefatigue:weldment;heatafectedz
8、one;grainboundarysegregation;hardnessdis
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