简介:
简介:本文针对N4/1Cr18Ni9Ti与N4/0Cr25Ni20复合板的特殊焊接要求,根据NB/T47014—2011《承压设备焊接工艺评定》的要求,制备2块N4/1Cr18Ni9Ti试板,2块N4I/0Cr25Ni20试板,尺寸均为500mmX150mmX(4+14)mm。不锈钢基层采用GTAW打底,焊丝选用HOCr21Ni10,SMAW填充与盖面,焊条选用A302与A402。镍复层的焊接采用手工钨极氩弧焊,焊丝选用含Ti、AI等脱氧元素的ERNi-1焊丝,保护气体选择98%Ar+2%H2。试板焊接完成,外观检验合格后进行100%RT,检测结果符合JB厂r4730,2—2005I级合格,镍复层进行100%PT,检测结果符合JB/T4730.5—2005I级。两种焊接试板分别取样并做拉伸、弯曲力学性能分析,镍复层焊缝做化学成分分析。通过两块焊接试板试验对比,不锈钢基层焊接材料选择HOCr21Ni10焊丝与A302焊条。镍复层焊接采用ERNi-1焊丝,焊接保护气体为98%Ar+2%H2。通过焊接工艺评定试验研究,解决了N4/1Cr18Ni9Ti与N4I/0Cr25Ni20复合板焊接问题,提高了用户坩埚的返修质量与再次使用寿命,为使用单位节约了成本。
简介:我国是铝的第一生产大国,但是在上世纪80年代初,因铝导体生产工艺低下严重影响了铝导体的使用。主要制约铝导体推广和使用因素是达不到国际公认的61%IACS导电率水平,以及与导电率相矛盾的断裂强度与伸长率,这就严重地制约了铝导体的使用。随着科学技术的不断发展,铝导体加工工艺的不断进步,人们想出了可在铝的熔炼过程中加入一些其他元素,来弥补铝导体性能的不足,发展到今天就形成了铝合金导体。从2005年开始,铝合金导体在电缆中的使用逐步发展起来,由于铝合金导体除了在导电率上与铜存在差距,在导体压蠕变、柔韧性、抗腐蚀以及电缆敷设方面都优于铜导体电缆,同时,在导电率上也可以通过扩大导体截面来弥补载流量的缺陷,从而人们也慢慢开始使用铝合金材料作为电缆导体。
简介:TiC/Cr18Ni8steelbondedcarbidesweresynthesizedbyvacuumsinteringwithmixedpowdersofiron,ferrotitanium,ferrochromium,colloidalgraphiteandnickelasrawmaterials.Themicrostructureandmicrohardnessofthesteelbondedcarbideswereanalyzedbyscanningelectronmicroscope(SEM),X-raydiffraction(XRD)andRockwellhardometer.ResultsshowthatthephasesofsteelbondedcarbidesmainlyconsistofTiCandFe-Cr-Nisolidsolution.ThesynthesizedTiCparticlesarefine.Mostofthemarenotmorethan1μm.Withtheincreaseofsinteringtemperature,theporosityofTiC/Cr18Ni8steelbondedcarbidesdecreasesandthedensityandhardnessincrease,butthesizeofTiCparticlesslightlyincreases.Underthesamesinteringconditions,thedensityandhardnessofsteelbondedcarbideswithC/Tiatomicratio0.9arehigherthanthosewithC/Tiatomicratio1.0.TheTiCparticleswithC/Tiatomicratio0.9aremuchfinerandmorehomogeneous.
简介:Theeffectofnonmetallicinclusionsinthedropletofthestainlesssteelcoveredelectrodeontheporositywasresearched.Theresultshowsthatthenonmetallicinclusionsinthedropletarespherical,theircompositionisdifferentfromtheoneofslagandtheinclusionshavethecharacterof"innerformation".Whentheratioofrutiletoilmeniteinthecoatedmaterialisincreased,thedropletbecomescoarse,thecontentofnonmetallicinclusioninthedropletdecreases,andtheporositysensitivityintheweldmetalalsodecreases.Whentheratiooffledspartoilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusioninthedropletincreases,andtheporositysensitivityintheweldmetalincreases.WhentheratioofFe2O3toilmeniteinthecoatedmaterialisincreased,thedropletbecomesfine,thecontentofnonmetallicinclusiondecreases,whiletheporositysensitivitydoesnotreduce.
简介:SolderingofLD31aluminumalloysusingSn-PbsolderpasteafterelectricbrushplatingNiandCucoatingswasnvestigated.ThetechnologyofelectricbrushplatingNiandCuwasstudiedandplatingsolutionwasdeveloped.Themicrostructureofthecoatings,solderedjointandfracturefacewereanalyzedusingopticmicroscopy,SEMandEDX.Theshearstrengthofsolderedjointcouldreachashighas26.83MPa.Theresultsshowedthatreliablesolderedjointcouldbeobtainedat230℃,theadhesionofcoatingsandLD31aluminumalloysubstratewashighenoughtobearthethermalprocessinthesoldering.
简介:TIGweldingwasusedtodepositCo-8.8Al-9.8W-0.2Bsuperalloyon304austenitestainlesssteel.Theformfactorofweld,dilutionratio,microhardness,microstructureanddistributionofalloyingelementswereinvestigated.Themicrostructureofcladdinglayerwasmainlyhypoeutectic.Theprimaryphaseswerecobalt-richsolidsolution.Theeutecticphasewascomposedofcobalt-richsolidsolution,Co6W6CandCoCx.Whentheboroncontentincreasedfrom0.2%to0.5%,thedilutionratiodecreased,theprimaryphasebecamecoarseandthemicrohardnessdecreased.Whentheboroncontentwasfrom0.5%to2%,thedilutionratioandmicrohardnessincreasedobviously,buttheprimaryphasewasrefined.ThehardphaseofCo-8.8Al-9.8Wbecamerefinedandtheamountwasraised,andtheperformanceofcladdinglayerwasimprovedwithappropriateboronincrease.