简介：ProblemsaboutsurfacemountingprocessforfinepitchdevicesandreasonsonsolderbridgingofLtypeleaddevicesweldedaredepicted.Bridgingmechanismandinfluencefactorsareanalyzedwithtwo-dimensionalgeometricmodel.Basedonthis,high-densitysurfacemounttechnology(SMT)forfinepitchLtypeleaddevicesheatedbyscan-ninglaserisraised.SurfacemountprocessforQFP208onprintedcircuitboard(PCB)isstudied.Theresultsoftestsarethatitisquitepossibletosolvethesolderbridgingofsurfacemountingforpitchdeviceswithscanninglaser-heat-ingmethod.

简介：904L是一种全奥氏体不锈钢,在焊接时易出现热裂纹,且晶间腐蚀和应力腐蚀开裂倾向较大。本文经可焊性分析后,从焊接材料和焊接工艺参数的选择入手,进行了焊接工艺性试验,找出了合适的焊接规范,并在实际产品的焊接中进行了严格的质量控制,生产出合格的产品。

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简介：Intheacceleratordrivensub-criticalsystem(ADS)cooledbyliquidPbBialloy,theausteniticstainlesssteel316Lisoneofthecandidatesofstructuralmaterials.However,thecorrosionandwearbehaviorof316Lsteelinthehigh-velocitystreamofliquidPbBiisthemostessentialissue,whichisurgenttobepaidcloseattention.Inordertoacquirethemorphologyandmechanicalpropertiesof316Lsteelintheconditionsofdifferentrelativeflowingvelocity(RFV),respectively2.62m/s,3.69m/s,4.77m/s,theexperimentwascarriedoutindynamicliquidPbBiat550℃,uptoabout1500h.Accordingtotheresults,thesurfaceof316LhasbeencorrodedbadlyandtheelementsofNi,Cr,etc.werefoundtodissolvealot.WiththeincreaseoftheRFV,thefeatureof316Lsurfacechangedfromthesurfacewithmuchdeeperpitsandlooserstructurestotherelativeplanarone,andthethicknessoftheouteroxidelayerdecreasedgraduallywhilethatoftheinneroxidelayerdiminishedalittle,andthemicrohardnessoftheoutermostsubstratealsodeclinedincreasingly,inaddition,thedomainofthepartialsubstratewithitsmicrohardnessbeingaltereddeepenedfurther.Theseexperimentaldatawouldoffertheoreticalbasisandpracticalvaluestostudycorrosionconditionof316LsteelinliquidPbBiwithhigh-velocity.

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简介：第五章展会期间著作权保护第二十二条展会投诉机构需要地方著作权行政管理部门协助的,地方著作权行政管理部门应当积极配合,参与展会知识产权保护工作。地方著作权行政管理部门在展会期间的工作可以包括:

简介：BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope（SEM）,electron.probemicroanalysis（EPMA）andX-raydiffraction（XRD）.theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.

简介：本文结合生产实践,简要分析提出了CO2气体保护焊目前所存在的缺陷与问题,并提出了相应的解决方法与CO2气体保护焊的发展趋势。

简介：ＡｖｉｓｉｏｎｔｒａｃｋｉｎｇｓｙｓｔｅｍｏｆｒｏｂｏｔＣＯ２ｓｈｏｒｔｔｒａｎｓｆｅｒｗｅｌｄｉｎｇＷｕＲｅｎｙｕ；ＷａｎｇＧｕｏｄｏｎｇａｎｄＬｉＸｉａｏｑｉ（ＴｉａｎｊｉｎＵｎｉｖｅｒｓｉｔｙ）ＺｈａｎｇＬｉａｎｃｈａｎｇ(ＭｏｔｏｒｏｌａＣ?..

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简介：多位权威专家表示,当前我国经济步入新常态,改革也步入深水区,亟待推动“二次开放”,以加快推进自贸区建设为路径,以服务贸易及服务业开放为重点,创造“二次开放红利”,带动我国经济发展进入新阶段。

简介：本文以图文并茂的形式阐述了埋弧焊机控制系统的进展,并对窄间隙埋弧焊和带极埋弧堆焊的设备类型、工艺特点、工艺参数等进行了系统的论述。

简介：本文介绍了CO2气体保护电弧焊的冶金特点，CO2气体保护电弧焊焊接过程中的熔滴过渡形式；从焊丝的冶金过程，焊接时的工艺参数的选择及调整等方面探讨了汽车白车身CO2焊接质量的控制。

简介：IntheautomaticCO2arcwelding,thealterationoftheverticaldistancebetweentheweldingtorchandtheworkpiecehasastrongeffectontheweldingparameterssuchasweldingcurrentandvoltage,withtheresultthattheappearanceandqualityofweldarenotsteady.Toweakentheinfluenceofthedistancealteration,amethodisputforwardinthepaper.Themethodisthatthealternatewire-feedcontrolisusedforcompensatingtheweldingcurrent.Onthebasisoftheoreticalanalysis,astaticnumericalmodelforalternatewire-feedcontrolisestablished.Theexperimentsshowthatthemodel-basedregulationofthewirefeedratecancompensatetheweldingcurrentandensuretheappearanceofweld.Whenthealterationofverticaldistancebetweenthetorchandtheworkpieceisgreater,notonlyisthewirefeedrateregulated,buttheoutputvoltageofthepowersourceisadjustedtoensuretheappearanceandqualityofweld.

简介：本文介绍了CO2焊工艺方法及其高效、优质、低成本的综合优越性以及在石油、化工、天然气工程建设中的应用与发展,不同种类的气体与焊丝相组合的工艺特点及控制焊缝成形的操作技术。

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简介：<正>(续上期)ASM全自动、宽温应力、应变监测仪★全自动、连续、长时间监测、记录★宽温下,温漂≤0.5ppm★可同时测不同材料的应力、应变、载荷★5.7″TFTLCD★下拉菜单,界面友好,参数设置极方便★量程大:0～±400000μ,分辨率高达0.1μ★可检测不同材料的残余应力★测试结果可海量纪录、列表、查询极方便

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简介：ThispaperintroducesabrazingprocessbetweenAl_2O_3ceramicandInvaralloy.Al_2O_3canbebrazedwithInvareffectively.TheinterfacialstructureofAl_2O_3/Invarjointcanbeexpressedas:Invar/Ag(s,s)+Cu(s,s)+Fe_2Ti(zoneⅠ)/Ag(s,s)+Cu(s,s)+Fe_2Ti+NiTi+Cu_3Ti(zoneⅡ)/Ag(s,s)+Cu(s,s)+Cu_2Ti+Al(s,s)+TiC+TiO(zoneⅢ)/Al_2O_3.Themaximumshearstrengthof139MPawasmeasuredforas-brazedAl_2O_3/Invarjointbrazedat850℃for25minor900℃for15min.

简介：针对某企业支架制造过程中采用二氧化碳气体保护焊，焊接接头出现大量未熔合缺陷，分析了未熔合产生的原因，并阐述了防止未熔合的措施。实践证明该措施有效地控制了未熔合缺陷，提高了焊缝合格率，获得了满意的焊缝质量，具有推广应用价值。同时，是否将“未熔合”焊接缺陷与“气孔和飞溅”相提并论，都是CO2焊时容易出现的缺陷，以引起同仁的重视。