t91钢焊接热影响区粗晶区韧性研究

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1、摘要T91钢焊接热影响区粗晶区韧性研究摘要T91钢具有良好的高温强度高温抗氧化性和抗腐蚀性是超临界发电机组完成主蒸汽温度由538向566过渡的首选材料T91钢的开发和研制对提高我国火力发电行业锅炉机组的容量和发电效率降低发电成本解决我国电力紧张的现状和我国国民经济与社会的发展具有重要的意义本文所研究的控制和预测T91钢的焊接CGHAZ的组织和性能及合适的焊接焊后热处理规范成果为国产T91钢材制造超临界发电机组提供技术支撑本文以T91钢焊接CGHAZ为主要研究对象采用焊接热模拟技术冲击试验硬度试验研究了T91钢CGHAZ的性能通过金相

2、分析扫描电镜透射电镜等研究了焊接热输入焊接层数焊后热处理等对T91钢CGHAZ的显微组织精细结构及性能的影响规律研究结果表明T91钢CGHAZ形成的粗大马氏体组织是引起韧性显著下降硬度增加的主要原因采用热处理使马氏体转变为组织细小的回火索氏体组织改善了CGHAZ的性能控制焊接热输入获得利于韧性的CGHAZ组织晶粒并采用770+4小时的热处理可以使T91钢在CGHAZ中获得高韧性关键词T91钢焊接热模拟热影响区粗晶区CGHAZ组织和性能热处理IABSTRACTSTUDYTHECGHAZTOUGHNESSOFT91STEELBYWELD

3、INGTHERMALSIMULATIONABSTRACTT91steelhaswellstrength,oxidationresistanceandcorrosionresistanceinhightemperature.Itisthepreferredmaterialfortheboilersteamtransferringfrom538to566inthesupercriticalgeneratingset.Itisbeneficialtoimprovetheboilerunitcapacitanceandimprovetheg

4、eneratingefficiencyofthethermalpowergenerationbyresearchanddevelopmentoftheT91steels,whichcansettletheshortsupplyoftheelectricpowerandcanservicebettertothedevelopmentofournationaleconomicandsocialdevelopment.Researchinthispaperprovideausefulreferenceforcontrollingandpr

5、edictionofthesupercriticalgeneratingsetT91steelweldingCGHAZandobtainaproperweldingconditions.TheCGHAZwasselectedastheresearchobjecttostudybymeansofweldingthermalsimulationinthispaper.MechanicalpropertiesofCGHAZweremeasuredbytensiletestsandhardnesstests.Theopticalmicros

6、copy(OM),scanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM)wereemployedtoanalysistheeffectsoftheweldingheatinput,numberofweldbeadandheattreatmentontheCGHAZtoughnessandmicrostructureoftheT91steel.Theresearchresultsshowedthatthecoarsemartensiteisthemai

7、nreasonoftheincreasinghardnessandimpairingtotheCGHAZtoughness,whichwasimprovedwithheattreatmentthroughpromotingthetransformationofthecoarsemartensitetothesmallgrainofthetemperedsobitic.Thefinalthermalcycleofmultiplayerweldshavenoinfluenceonthemicrostructureandmechanica

8、loftheCGHAZoftheT91steel.TheweldingheatinputiscontrolledandthemicrostructurewhichisgoodforthetensileisgottenTheheattr