简介:Inthelastthreedecadesnewstrongermodified9%Crsteelshavebeenintroducedinnewpowerplantswithsteamparametersupto300bar(1bar=10~5Pa)and600℃.Inordertofurtherincreasethesteamparametersofsteelbasedpowerplantsuptoatargetvalueof650℃/325baritisnecessarytodoublethecreepstrengthcomparedwithtodaysstrongest9%Crsteels,andatthesametimetheresistanceagainststeamoxidationmustbeimprovedbyadding12%Crtothesteel.However,sofarallattemptstomakestronger12%Crsteelshavebeenunsuccessfulbecausethehighchromiumcontentintroducedseveremicrostructureinstabilitiesinthetestedsteels.Recently,itwasfoundthatthemicrostructureinstabilitiesin11%-12%CrsteelscanbeexplainedbytheprecipitationofcoarseCr(V,Nb)NZ-phases,whichdissolvefine(V,Nb)Nnitrides.AnewpossibilitytousetheZ-phaseforstrengtheningof12%Crsteelshasbeenidentified,andthedevelopmentofstablestrongmartensitic12%Crsteelsbasedonthisconceptisexpectedtoallowtheconstructionof325bar/650℃steampowerplantsallbasedonsteel.
简介:本文从酒钢3×6000Nm~3/h制氧生产工艺及其控制设备的现状出发,介绍了改造后DCS控制系统软、硬件的构成和实现的主要功能,取得了良好的应用效果。
简介:Coarsening,embrittlementandcorrosionsensitizationinahightemperatureheat-affectedzone(HTHAZ)arethemajorproblemswhen12%chromiumlowcarbonstainlesssteelisbeingwelded,whichinducethedeteriorationoftheimpacttoughnessatalowtemperatureandintergranularcorrosionresistanceproperty.ThisstudyinvestigatesthecorrespondingmicrostructuresinHTHAZwithdifferentchemicalcompositionsandheatinputsthroughthermalsimulationtests.Theresultsshowthatthemartensitecontentincreaseswiththedescendingofferritefactor(FF)whenFFisbelow9.0andheatinputinfluencesthemicrostructureofhighFFsteelinHTHAZ.Martensiteof12%CrstainlesssteelinHTHAZwithonlyNbstabilizationreticularlydistributesatferritegrainboundaries.