简介:利用扫描电镜观察和能谱分析,研究了A709-50T-2结构用钢探伤不合格的原因。结果表明:中心偏析和大块Nb和Ti的碳或氮化物的形成共同作用,使钢板中心产生裂纹,最终导致了探伤的不合格。
简介:Throughsummaryandextractionofcurrentsteelmakingdesign,processandequipmenttechnologiesandproductiontechnologiesfor300tgradeconvertersinBaosteel,thearticleanalyzesandelaboratesthesignificanceofindependentintegrationof300tgradeconvertersinZhanjiang,majortargetsoftheindependentintegrationinconverterprocesstechnologies,equipmentpackagesandcontrols,theinnovatedcriticaltechnologiesandcomparisonwithoverseasadvancedtechnologies,majortechnicaldifficultiesintheintegrationinBaosteelandtheirsolutions,aswellasgeneralmindsetandfinalobjectivesoftheproject.ThetotalintegrationoftechnologyforShanghaiNo.1SteelMakingPlantofBaosteelwasundertakenbyNipponSteel.AndKawasakiSteelwasresponsibleforthetotalintegrationoftechnologyfor4#and5#convertersofShanghaiNo.2SteelmakingPlantofBaosteel.Basedondigestion,absorptionandinnovationoftheintroducedtechnologies,Baosteelhasfirstlyachievedtheindependentintegrationof6#converter,5#RHand3#LFprojectsintheShanghaiNo.2SteelmakingPlantofBaosteel.Therefore,BaosteelshalltakeadvantagesofthefavorableconditionsandexperiencesandadvancedsteelmakingtechnologiesofBaosteeeltomastertheimportednewsteelmakingtechnologiesintheworldandthenformtheadvancedcompletesetsteelmakingtechnologiesandequipmentathomeandabroad.TheachievementofindependentintegrationofZhanjiangSteelMakingProjectwillmakethebreakthroughfortheconstructionoflarge-sizedsteelmakingplantinBaosteel.300tconvertertechnologyintegrationisundertakenbyBaosteelindependentlyininsteadofbytheforeignsideinthepast.
简介:The18Ni300gradecobalt-freemaragingsteelT300wassuccessfullymanufacturedonanindustrialscalebyapplicationofvacuuminductionmelting(VIM)andvacuumarcremelting(VAR)processatBaosteel.WiththecontentofOandNlessthan15ppmand10ppmrespectively(1ppm=10-6),theT300steelproducedbyBaosteelobtainedahighdegreeofpurityandagoodcombinationofultra-highstrengthandfracturetoughness.Theeffectsofsolutiontemperatureandageingtemperatureontensilepropertyofsolution-treatedandagedT300steelwereinvestigated.Theresultsshowthatthesolutiontemperatureslightlyinfluencesthestrengthofthesolution-treatedsteel,indicatingthatthesolutionstrengtheningratherthanthegrainboundarystrengtheningismoreimportanttothesolution-treatedsteel.Forthesolution-treatedT300,theelongationandreductionofareadon'tchangemuchwitharisingsolutiontemperature,andremainabove17%and70%respectivelyatthesolutiontemperaturerangingfrom800℃to1200℃.FortheagedT300steel,thestrengthandelongationarereducedwithanincreasingsolutiontemperature,andthesolutiontemperaturehasagreatereffectonthereductionofareathanthatontheelongation.Thereductionofareaoftheagedsteelreachesahighpeakwhenthesolutiontemperaturereaches920℃.Theexperimentaldataindicatesthatprecipitationstrengtheningmakesacontributionof1100MPatothetensilestrengthoftheagedsteel.Theageingtemperatureexertsagreatereffectonthestrengththanontheelongationandreductionofarea.Thesteelachievesabettercombinationofstrengthandtoughnessatthepeakageingtemperatureof500℃.