简介：ThispaperdealswithastudyonSnPbandlead-freesolderedjointreliabilityofPLCCdeviceswithdifferentleadcountsunderthreekindsoftemperaturecycleprofiles,whichisbasedonnon-linearfiniteelementmethod.Byanalyzingthestressofsolderedjoints,itisfoundthatthelargeststressisattheareabetweenthesolderedjointsandtheleads,andanalysisresultsindicatethatthevonMisesstressatthelocationslightlyincreaseswiththeincreaseofleadcounts.ForPLCCwith84leadsthesolderedjointswasmodeledforthreetypicalloading(273-398K,218-398Kand198-398K)inordertostudytheinfluenceofaccelerationfactorsonthereliabilityofsolderedjoints.Andtheestimationofequivalentplasticstrainofthreedifferentlead-freesolderalloys(Sn3.8Ag0.7Cu,Sn3.5AgandSn37Pb)wasalsocarriedout.

简介：Thedigitalizationofarcweldingpowersourcemainlydependsonthedigitalizationofarcweldinginverter,sothatmaincircuitandcontrollingsystemcangivefullplaytoadvantages.DigitalswitchingcontrolmakesmaincircuitdigitalandDSPand/orMCUmakescontrollingsystem,digital.SoIGBTdrivingcircuit,asatieofmaincircuitandcontrollingsystem,shouldalsobegotdigitalized.Thus,adigitaldrivingcircuitbasedonoptocouplerdeviceHCPL-316Jisprovided.Sometestingexperimentsweredone.Afterdrivingtesting,thedrivingcircuitcertificatesthatdrivingwaveformssatisfytherequirementsofarcweldingpowersourceandthedrivingcircuitisreasonablyandsimplydesigned.Andthedrivingcircuithashighcontrollingprecisionandreliability.No-load-voltagetestingandweldingexternalcharacteristictestingprovethatthedrivingcircuitcanbeappliedinarcweldingpowersource.

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简介：Inthispaper,themicrostructureandhardnessofHG980Dheat-affectedzone(HAZ)atdifferentcoolingratet8/3werestudied,theimplantcriticalfracturestressunderthreediffusiblehydrogenconditionsweremeasured,andthehydrogen-inducedcracking(HIC)fractographofsteelHG980Dwereanalyzed.TheexperimentalresultsshowthatmartensiteexistsinHAZofHG980Dtillt8/3≥150s,thehardenquenchingtendencyofHG980Disgreater;Theimplantcriticalfracturestressisrelatedtodiffusiblehydrogencontentsignificantly,atlowhydrogenlevel,highrestraintstressisneededtonucleateHIC,thefractographismainlymicrovoidcoalescence,butathighhydrogenlevel,onlysmallrestraintstresscancauseHICoccurrence,thefractographismainlyquasicleavage.Itisveryimportanttochooseultra-lowhydrogenweldingconsumabletoweldsteelHG980Dtopreventhydrogen-inducedcracking.

简介：Microstructuresandmechanicalpropertiesoftransientliquidphase(TLP)bondedmagnesiummetalmatrixcomposite(MMC)jointsusingcopperinterlayerhavebeeninvestigated.Withanincreaseofbondingtimesfrom5minto50minatbondingtemperatureof510℃,theaverageconcentrationofcopperinthebondedzonedecreased,themicrostructureinthezonechangedfromCu,α-MgandCuMg2toα-Mg,CuMg2andTiC,andmechanicalpropertiesofthejointincreased.Theshearstrengthofthejointbondedat510℃for50minreached64MPaduetothemetallurgicalbondingofthejointandimprovingitshomogeneityofcompositionandmicrostructure.ItisfavorabletoincreasethebondingtimeforimprovingmechanicalpropertiesofTLPbondedmagnesiumMMCjoint.

简介：本文介绍了超快恢复二极管(FRED)模块的工艺结构和内部接线图,略述了其特性参数和应用领域,以及高频应用领域内节电、节材、提高产品质量和劳动生产率的重要作用。

简介：本文对活性剂在管板全位置焊接中的应用进行了研究。在不开坡口的情况下,将活性剂刷涂到角焊缝待焊区域,对壁厚为3mm的低碳钢管板角伸出焊缝施焊,通过试验确定了最佳的焊接工艺参数,所得的焊接接头性能满足相关标准。这扩大了活性剂的使用范围,突破了管板全位置焊接厚壁管时需开坡口的局限性,减少了角焊缝的焊丝填充量,节约了焊接成本,大幅度提高了焊接效率。

简介：本文所阐述的一种直缝埋弧焊管的焊接导向机构，由支架、可拆卸的导向滚轮和调节手柄组成，既可支撑平衡钢管施焊时的稳定，又可配合各种规格钢管的焊接坡口调换不同的导向滚轮，调节焊道的直线度进行灵活施焊。

简介：本文通过对φ419×70,10CrMo910厚壁管焊接、热处理工艺与焊接接头性能进行分析,确定在焊接、热处理过程中合理的焊接工艺、热处理工艺对焊接接头质量及高温抗蠕变性能的影响,对提高此种管子的运行寿命有一定的意义,并有针对性地提出合理的焊接、热处理工艺及在焊接过程中易产生缺陷的防范性措施。

简介：通过大唐三门峡二期工程2×600MW超临界机组4~#机的施工,从组合方案、焊接工艺、热处理工艺的角度对哈尔滨锅炉厂生产的HG-1900/25.4-YM4锅炉的高温再热器安装工艺进行总结,介绍如何在保证施工质量的前提下减短工期,加快生产进度。