高温后Q235钢材力学性能试验研究-丁发兴

9220064　　　　　JOURNALOFBUILDINGMATERIALS　Vol.9,No.2Apr.,2006:2005-01-14;:2005-06-18:(50578162);(03JJY3089):(1979-),,,.　　:1007-9629(2006)02-0245-05Q235丁发兴,　余志武,　温海林(,410075):通过对高温后Q235钢材力学性能的试验研究,描述了高温后钢材的表面特征,探讨了钢材受热温度和恒温时间对高温后钢材力学性能的影响,并建立了高温后钢材屈服强度-受热温度、极限强度-受热温度、泊松比-应力比和拉伸应力-应变关系曲线拟合方程.试验表明:随着受热温度的升高,高温后钢材的屈服强度、极限强度整体上呈降低趋势,而弹性模量和泊松比则基本不变;恒温时间对力学性能的影响不太明显;所拟合的高温后钢材屈服强度—受热温度、极限强度—受热温度、泊松比—应力比和拉伸应力—应变关系曲线方程均与实测结果吻合较好.:高温;钢材;拉伸应力-应变全曲线;力学性能:TU511.3+7　　　:AExperimentalResearchonMechanicalPropertiesofQ235SteelafterHighTemperatureTreatmentDINGFa-xing,　YUZhi-wu,　WENHai-lin(SchoolofCivilArchitecturalEngineering,CentralSouthUniversity,Changsha410075,China)Abstract:InexperimentalinvestigationonmechanicalpropertiesofQ235steelafterhightempera-turetreatment,surfacecharacteristicandinfluencesoftheimportantparametersincludingheat-ingtemperatureandtemperatureexposuretimeonthemechanicalpropertiesofsteelafterhightemperaturetreatmentwerestudied.FormulasforPossion’sratio-stressratio,tensilestress-strain,yieldstrength-heatingtemperature,tensilestrength-heatingtemperatureofsteelafterhightemperaturetreatmentareproposed.Theresultshowthat:withtheheatingtemperaturerising,yieldstrengthandtensilestrengthtendtodecreaseasawhole,whileelasticmodulusofthesteelandPossion’sratioalmostremainunchanged;withincreasingtemperatureexposuretime,themechanicalpropertiesofthesteelafterhightemperaturetreatmentarehardlyinflu-enced;thecalculatedresultsbyabove-mentionedformulasagreewellwithtestones.Keywords:hightemperature;steel;tensilestress-strainrelationship;mechanicalproperty　　,().[1～6],、,-;,[3～6],,-.,[7～9],,、,-、—.,Q235,[7～9],—、—、——.1　　　Ф165mm×3mmQ235,500mm×20mm×3mm.,1,1200℃.20(),200,400,500,700,1000,1100℃.200℃700℃1,2,3h,2h.(Q235),.(2).《》(GB/T228—2002),:,,,7d,.2　2.1　　　,:200℃,;400～500℃,,,;700℃,;1000～1100℃,,,,1100℃().[7],[7].2.2　　　(1)　1fs(t)、fu(t)、Esνs().1,,、,.,.(2)　1.1,700℃,.2.3　2.3.1　(1):400℃,;400～700℃,;,,1000℃40%.Q235()Q235[9](),fs(t)fs=1-6.4×10-6t-201005　　t≤1000℃(1)246　　　　　9　1　Table1　MechanicalpropertiesofsteelafterhightemperaturetreatmentCodet/°CTime/hEs×10-5/MPafs(t)/MPafu(t)/MPaνs20-22022.14334.0423.00.270200-120012.08343.0436.70.267200-220022.05346.1445.90.254200-320032.14333.7420.40.265400-240022.06358.3398.30.266500-250022.12316.4383.90.264700-170012.17323.0370.40.260700-270022.13296.4366.60.269700-370032.06308.1380.60.2671000-2100022.13138.1226.30.250fs.,0.2%.　　600℃,[7]fs(t)fs=1　　t≤400℃1+2.23×10-4(t-20)-5.88×10-7(t-20)2　　t400℃(2)　　800℃Q235,[8]fs(t)fs=1　　t≤330℃1.1-3.0×10-4t　　t330℃(3)　　(1)～(3)2.2,780℃,(1).1　Fig.1　Temperature-timecurve2　Fig.2　Yieldstrengthofsteelafterhightemperaturetreatment2.3.2　(1),200～1000℃,2.05×105～2.17×105MPa,(2.14×105MPa).,.[9].2.3.3　(1):400℃,;400～700℃,;,,1000℃50%;200℃,.Q235()Q235247　2:Q235　　　[9](),fu(t)fu=1-5×10-5t-201004　　t≤1000℃(4)fu.800℃Q235,[8]fu(t)fu=1　t≤347℃1.08-2.3×10-4t　t347℃(5)　　(4)、(5)3.3,620℃,(4).2.3.4　(1),200～1000℃,0.250～0.269,0.265,(0.270).,..,,0.8fs,fsνs=0.5,0.8fs～fs.,,νs=0.45,,.,νs=ν0　y≤yaνf-(νf-ν0)1-y-ya1-ya2　yay≤1νf　y1(6):ν0;νf;y,y=σ/fs(t),σ;ya.,ν0=0.265,νf=0.45,ya=0.8.420℃200,1000℃,(6).4:((6)).3　Fig.3　Tensilestrengthofsteelafterhightemperaturetreatment4　Fig.4　RelationbetweenPossion’sratioandstressofsteelafterhightemperaturetreatment3　-　　(20℃)200,500,700,1000℃-5.5,-,-.,(7)[1,2].248　　　　　9　σ=(Es-Etst)ε(1+(Es-Etst)εfs(t)nt)1/nt+Etstε　ε≤εtufu(t)　εεtu(7):Etst;nt-;ε;εtu,(7)、.,(7):Es=2.06×105MPa;Estt=0.01Es;nt=10.(7)5.5,-((7)).5　-Fig.5　Tensilesturess-strainrelationshipsofsteelafterhightemperaturetreatment4　　　1,.2.-、-、——,Q235.:[1]　OKABETakeshi,ABETakeo.Buckingstrengthofsteelcolumnsusingfireresistantsteel(NSFR490A)athightemperature[J].JStructConstrEng(AIJ),2000,535(5):171-178.[2]　OKABETakeshi.Buckingstrengthofsteelcolumnmodelsusingnewmetallicstructuralmaterial(SA44OB)athightempera-ture[J].JStructConstrEng(AIJ),1999,521(7):169-176.[3]　　.()[J].,2000,30(10):61-63,67.[4]　.[J].,2000,30(4):26-28.[5]　,　.Q345[J].,2001,31(1):.53-55.[6]　　,.Q235—[J].,2004,38(6):967-971.[7]　.[D].:,1998.[8]　,,,.[M].:,1994.[9]　　.[D].:,2000.249　2:Q235