简介:为了对高合金异种钢焊接工艺有更多的了解,本文通过对某火力电厂锅炉后屏过热器检修换管过程中涉及到的钢种(SA213-T91马氏体高合金耐热钢与Cr25Ni13奥氏体高合金耐热钢)的现场焊接工艺进行介绍,以给类似工程的施工提供一定的借鉴。
简介:摘要:双向不锈钢022Cr25Ni7Mo4N因其具有良好的耐腐蚀性、强度和韧性而广泛应用于化工、石油等工业领域。然而,双向不锈钢的焊接性能较为复杂,焊接过程中易出现焊接变形、裂纹等问题。因此,针对022Cr25Ni7Mo4N双向不锈钢的焊接工艺进行研究和分析具有重要意义。
简介:SomenewNi-saving25Crduplexstainlesssteels(DSS)havebeendeveloped.Theresultsindicatethatthealloyhasabalancedferrite-austeniterelationafterhotforgeandsolidsolutiontreatmentat1000℃.TheelementsWandCuhaveamarkedeffectonthemicrostructureofthealloy.ThepittingpotentialofthesteeladdingWandCuelementsreachesthemaximumvalueof435mV.Thetensilestrengthandpercentageofareareductionofallsteelsinthispaperare800-900MPaand60%-70%,respectively.Thetensileelongationsofthealloysareallabove30%.Theexperimentalsteelshavegoodcorrosionandmechanicalproperty.
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:Themechanicalandcorrosivepropertiesof00Cr13Ni4Mo(S13-4N)weretestedandcomparedwiththoseof00Cr13Ni6Mo(S13-6).Theeffectsofnitrogenonthepropertiesofthesteelswereanalyzed.Theresultsofthetensileandcorrosiontestsshowthestrength,theductility,andthepittingcorrosionresistanceofS13-4Narehigher,lowerandpoorerthanthoseofS13-6respectively,whentemperedatatemperaturebelow550℃andviceversawhenthetemperingtemperatureishigherthan550℃.TheresultsoftheX-raydiffraction(XRD)andtheelectronbackscattereddiffraction(EBSD)analysesrevealthatinversedausteniteappearsat550℃andtheamountofitpeaksat600℃withthebestductility.AndthetotalamountoftheinversedausteniteinS13-6ismorethanthatinS13-4Nindifferentforms.Nitrogenperformsbetterintermsofstabilizinginversedaustenitewhilenickelismorefavorableforforminginversedaustenite,theamountandstabilityofwhichaffecttheductilityremarkably.ThereasonfortheembrittlementofS13-4Nat450℃canbetheresultofcarbideandnitrideprecipitatingatgrainboundaries.
简介:Improvingtheunitheatefficiency,reducingcoalconsumptionandtheemissionofCO2andmeetingtherequirementsofenvironmentalprotectionandenergyconservationisthegoaloftheboilerandthepowerindustry.Developmentsoflargecapacityandhighparameterultra-supercritical(USC)unitsarethetendencyofthepowerindustry.ThereisnodoubtthatthedevelopmentofUSCunitsisbasedonthedevelopmentofmaterials,especiallythematerialsusedforsuper-heaterandreheaterinhigh-temperatureUSCboiler.Duetothelongtimeexposuretotheharshenvironment,suchasbearingthe600℃steamoxidation,andwithstandingthecorrosivefluegasandflyasherosion,thematerialsrequirenotonlygoodhigh-temperaturestrength,butalsoagoodcorrosionresistance.Inconsiderationoftherequirementscitedabove,foreigncountrieshaddevelopedTP310HCbN(07Cr25Ni21CbN)austeniticheat-resistantsteel.However,thedomesticdemandsforthismaterialstilldependonimportandthecostishigh,sotheboilerandthepowerindustryexpectseagerlythatthesesteelscanbeproducedbydomesticmetallurgicalindustry,especiallyBaosteel,toreplacetheimportedproducts.Inordertosatisfytherequirementsofdomesticmanufacturingsuper-heaterandreheaterusedinultra-supercriticalpowerboiler,afterdevelopedT23、T91、T92、S30432highpressureboilertube,BaosteelbegantodevelopTP310HCbN(07Cr25Ni21CbN)austeniticstainlesssteeltubeinJanuaryof2007.Thisstudydescribesthecompositiondesign,themanufacturingprocessofproduct,andtheassessmentofperformanceofBaosteel’sTP310HCbN(07Cr25Ni21CbN).ThedataindicatesthatpropertiesofBaosteel’sTP310HCbN(07Cr25Ni21CbN)conformtotheASMESA-213standardandGB5310standard,soitcansubstitutetheimportedproductsandissuitableformanufacturingpowerstationboilerofgreatcapacityandhighsteamparameters.
简介:PrecipitationstudywascarriedoutinNi-35at.pctCralloybymeasuringelectricalresistivityatdifferentageingtemperaturesandlongageingtimes.Duringageing,itwasobservedthatelectricalresistivityinitiallyrosewithageingtimeandthenfellafterverylongageingataconstanttemperature.TheinitialincreaseinresistivityduringageingmaybeattributedtotheformationofGPzones/Cr-richprecipitatesatearlystagesbynucleationprocessanddecreaseinresistivity,andafterattainingamaximum,isduetothegrowthofprecipitateparticlesandsubsequentlybycoarseningoftheseprecipitates.TheresultsofelectricalresistivitymeasurementsduringageingwereconfirmedbyX-raydiffractionanalysisindicatingtheformationofaCr-richphaseandaCr3Ni2phaseintheNimatrix.
简介:1Cr18Ni9Ti不锈钢球头在焊接后经酸洗,表面存在粗糙的腐蚀凹坑。通过采用S-3700N扫描电子显微镜、能谱分析仪、金相显微镜等对表面粗糙的腐蚀凹坑进行成因分析。结果表明:球头在焊接过程中产生了局部敏化现象,球头的晶粒组织细于与之配合的外套螺母组织,使得球头的耐腐蚀性低于外套螺母,在酸洗去氧化皮的过程中,外套螺母与球头的焊缝区、接管嘴的焊缝区之间形成缝隙,酸洗液中的正负离子移动受到了阻滞,导致缝隙处发生严重腐蚀,最终表现为球头表面的点状腐蚀形貌。定期更换酸洗槽液,降低Cl-浓度,以及在酸洗过程中活动零件,可以减少该类腐蚀的产生。
简介:0Cr18Ni9不锈钢薄壁产品在酸洗过程中易发生过腐蚀。本研究采用0.1mm厚度0Cr18Ni9不锈钢带,对酸洗的各影响因素进行试验研究,结果表明:材料状态不同,耐腐蚀能力不同,退火态更易出现过腐蚀;酸液温度、浓度及酸洗的时间均对不锈钢带腐蚀程度和力学性能有较大影响;在含HF的腐蚀剂中酸洗容易使薄壁不锈钢带力学性能降低,造成材料脆化,且HF含量越高对薄壁不锈钢力学性能影响越大。
简介:摘要:1Cr18Ni9Ti不锈钢因其具有优良的化学稳定性,在电力及石油化工行业得到日益广泛的应用,特别是在需要耐酸及耐高温管道中应用较广。因其介质多为易燃、易爆及有毒物,且压力较高,因此,对焊接质量要求很高。以往我们对于1Cr18Ni9Ti不锈钢厚壁管均采用TIG焊或手工电弧焊焊接,前者效率低,成本高,后者质量难以保证且效率低。为即保证质量又提高效率,我们进行了大胆尝试,采用TIG内外填丝法打底,MAG焊填充及盖面。经查阅有关资料及反复试验后,效果良好,质量效率都得到了保证,值得向大家推荐。