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46 7 Vol.46No.72010 7 844—849 ACTAMETALLURGICASINICAJul.2010pp.844–849HR3C ∗ 1) 1) 1,2)1) , 1160852) , 116085 HR3C 750 500h . , HR3C M23C6 NbCrN, M23C6 ,NbCrN ; M23C6 NbCrN HR3C . M23C6 3 , , M23C6 Cr σ . HR3C , , , TG132.33 !#A $% 0412−1961(2010)07−0844−06PRECIPITATESINHR3CSTEELAGEDATHIGHTEMPERATUREFANGYuanyuan1),ZHAOJie1),LIXiaona2)1)SchoolofMaterialScienceandEngineering,DalianUniversityofTechnology,Dalian1160852)KeyLaboratoryofMaterialsModificationbyLaser,IonandElectronBeamsofMinistryofEducationDalianUniversityofTechnology,Dalian116085Correspondent:ZHAOJie,professor,Tel:(0411)84709076,E-mail:jiezhao@dlut.edu.cnSupportedbyHighTechnologyResearchandDevelopmentProgramofChina(No.2006AA04Z421)Manuscriptreceived2010–01–19,inrevisedform2010–04–19ABSTRACTHR3Csteel(Fe–25Cr–20Ni–Nb–N)isanewtypeofausteniticheat–resistantsteelwhichhasbeenwidelyusedforsuper–heaterandre–heatertubesintheultrasupercriticalpressure(USC)boiler.ThemechanicalpropertiesofHR3Csteelweredependentonthestabilityofthemi-crostructure,particularlythelargeamountofprecipitatesformedduringservice.ThisworkwasfocusedonthechangeofmicrostructureandtheprecipitationsofHR3Csteelafterthermalagingfor500hat750 .TheresultsindicatedthatthemajorprecipitateswerevariformM23C6carbidesandNbCrNnitrides.M23C6carbidesprecipitatedongrainboundariesandinintragranular.FineanddispersedNbCrNnitrideswerefoundtoprecipitateinintragranular.ThehardnessofHR3CsteelhadbeenimprovedthroughdispersedM23C6andfineNbCrNprecipitatesafterthermalagingfor500hat750 .AlltheM23C6carbides,withlatticeparameterofthreetimesoftheaustenitematrix,growninacubetocubeorientationrelationshipwiththematrix.SomeoftheM23C6carbideswhichprecipitatedongrainboundariesweretransformedintoσphase.KEYWORDSHR3Csteel,thermalaging,precipitation,microstructure (SC) (USC) & ! , # , $ . & % & #’$! .! &$ ##( ) $$!#.*$% &% ’()!&2006AA04Z421’*+*#$:2010–01–19,’*(+*#$:2010–04–19’#,-:.$$,%,1984&),*+)DOI:10.3724/SP.J.1037.2010.00037/’,,%! &$ ,&0 ’,TP347HFG,Super304H,NF709(20Cr–25Ni–1.5Mo–Ti–N)1HR3C(25Cr–20Ni–Nb–N)-$-()[1].2(3 Cr1Ni$$-.. ()HR3C*()+$,-//.1,40. , &0 * ! 6200/31.5MPa$USC &$5)/1+)/1,0 ,1620—6800[1,2].-$-$.. ().,HR3C2,/2(326703$( .1*670332,0 53.454$5,62383,6709:1/.873&48,5HR3C$ 7 ;669:HR3C=9:; 7:;=8454545,6=?8.Park-[3]?57HR3C9?@@Nb1N$25Cr–20Ni1SUS310S$-/6A1 N-HR3C.$:;( .Iseda-[4]2 HR3C-7000B$@C-/A&=/.$/B, -500—7500B@3C 53.$&=DA/.Komai-[5]BC D?-Eddystone#@1C &5)/1 @E75075h$HR3C$ED9: A/..1*HR3CC A$5,4E083,FF27σ42Æ-!.5,G(A1,5G,7HR3C5,4$B4FHGI ,H2.1*@JC 53.,4545C$5,ID9( 53.$KH5,536-!,ILE MN#COEIP7HR3C C A5,$454$/ 5,$QF- 6DJ1J5.1*! ?R?K$L7KÆ -6000—8000[4,6,7],IL -7500B8’KÆ.1)*+,KÆ $HR3CMKG13mm$L(,BA%J(D9J ,%):Cr24.00—26.00,Ni17.00—23.00,Nb0.20—0.60,Mn2.00,C0.04—0.10,N0.15—0.35,FeH9.!L(-G10930 65M:N;.6G 5$L1=SI,N0-7500BC 500h.NGC $M:TSI1C T$SI 6O?O,P 100g/L$QU:J 6#P40,-MEF–3-OAOE@(OM)B 674&=DJ. QJ 10%$HCl:J7C 500h$SI-=A,P XRD–6000-XNVKNL(XRD)7-=,$454 6J5.P .AJ5(EDS)J5454B5$%J. 6RWERDJ1J5454,JF6M:T1C 500h$SI1=KG0.5mm$ÆC,M50—70μm,P MTP–1A-XD ÆL ÆA, TecnaiG220S–Twin-MN#COE@(TEM)B 6 JSDJ1 E#CKN(SAED)J5.2)*./0122.1HR3C34567Æ89:;=7M:T1C A$HR3C 6ED&=DJ,0YFGZ1[H.6Z16S,M:T$HR3CT .T-&9$B5N\D;9M:TSI43,C AHR3C$H UKIO.C A$HR3CH (454T-.3H5JU ],C A$SI.HJ2(454B5T-,0O VW3W^KJX3L_.2.2?@HR3C3ABCDEFÆG:;HIZ2H, M:THR3C$TEM‘ HJ454$EDSJ59V1(SAED)A.1Z6S,M:THR3C$HJT-B5N\D,-TEMB*(?!$VW1YN,0Y-YFGZ2a[H;96EDSJ5(Z2c)1SAEDA(Z2a.ZZ),M:TSI.$BJ1 HR3C OMaFig.1Metallographofinitial(a)andaged(b)HR3Csteel(ageingat750[for500h)5N\DW\bX9:$NbCrN,0VW0.2—0.5μm,-TEMB0P;YFXY1QY;M:THR3C$H NM(454T-,T-&9Q],GZ2b[H.96Z16R,M:THR3CT .2(4545CNbCrN,KYN1VW?!,H NM(IO$4545CT-.2.3457HR3C3ABCDEFZ3#, C AHR3C-=YN$XRDA.1Z6R,-7500C 500hAHR3C.T-M23C6,NbCrN σ4-.7 SI 6 TEMDJ, ,H7HR3C-C 53.5$4545C$/ 5,QF 64A.2.3.1KLMHR3CNOPQRSTUVWZ4TEMBDJ$C AHR3C$H YF #CKNZA.6S,C 53.HR3C-H 5,$4545CP;M23C6.6Z4a.6O,,M23C6cB\-HR3C.S%H 5,.EDS9V(Z4d)OHC AHR3C.$M23C6$P;%JCr1Fe.M23C6-H $YF17@Xd(^T.UJM23C6S%H 5,17@,/e_B5PZ%$QN9:;($M23C6S%H 5,7@A,UV[-W($H M23C61,f%HJ7@_\NM23C6.Z4a.2/?!YF$M23C69T $#CKNAJFGZ4b1c[H.Z.&$R‘aT KN‘,^$b‘aM23C6$KN‘,Z4c.T $KN‘ ^QScH.M23C6fcc9:,T γ4,?5J56846]gXd 46 J2^ThHR3C iY TEMa EDS SAEDUFig.2TEMimagesofagrain(a)andgrainboundary(b)ofinitialHR3CsteelandEDSresultofsecondphaseparticle(c)(insertinFig.2aistheSAEDpatternofsecondphaseparticle)J3 HR3C XV WZ XRDUFig.3XRDpatternoftheextractedsecondphaseparticleinagedHR3CsteelR,X[eL%j _$?k,KM23C6$H_K T $3f.M23C69T $=f?k:(020)γ//(020)M23C6,[100]γ//[100]M23C6.-Z4a$YBXDJgS%H 5,$M23C6&0JFS%H fXH5JU7@,%2lhY$‘m9:,.a,],Z3[m$E\.Z5M23C6JJ4 HR3C M23C6n Fig.4M23C6precipitatedatgrainboundariesinagedHR3Csteel(a)TEMimageofM23C6(b)diffractionpatternfromangularityM23C6(c)diffractionpatternfromrodlikeM23C6(d)EDSresultofM23C6J5 HR3C \M23C6b o p TEMaFig.5TEMimageofanewphasebetwe