4 / SimulationandOptimizationofHeatTreatment ProcessforLargePressDieHolder,, (, ) FAN Meng-ting,SUN Ming-yue,LIDian-zhong (InstituteofMet

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1 4 / SimulationandOptimizationofHeatTreatment ProcessforLargePressDieHolder ( ) FAN Meng-tingSUN Ming-yueLIDian-zhong (InstituteofMetalResearchChineseAcademyof SciencesShenyang110016China) : 55NiCrMoV7 CCT ABAQUS CCT : ; 30min : ; ; :TG151.2 :A : (2011) Abstract:Databaseofthermal-physicalparametersandCCTcurvesof55NiCrMoV7steelwerefirstly obtainedbyexperimentalstudy.basedonthecommercialfemsoftwareabaqusthemodelsofoil- quenchingandwater-quenchingforalargepressdieholderwereestablishedseparatelythetempera- tureandstressevolution werecalculatedforeachprocess.combined withthecoolingratesofeach nodeandcctcurvesof55nicrmov7thefinalmicrostructureandstressdistributiononthediehold- erwerepredicted.accordingtothefemresultsupperbainitecanbeobtainedinthesurfacelayerby oilquenchingwhilelowerbainitecanbeobtainedunderwatercoolingcondition.howevercracks areeasilygeneratedintheinnerchamferbywaterquenchingbecauseoftheseverestressconcentra- tion.onbasisoftheanalysisdoublequenchingprocesswasproposedtoavoidcrackandobtainlower bainitethesimulationresultsshowthat30min water-coolingbeforeoil-coolingisfavorabletoward safeproductionandoptimizingthemicrostructureofthedieholder. Keywords:pressdieholder;quenching;finiteelementmethod (FEM) 5CrMnMo [12] 3680mm 85t55NiCrMoV7 5CrNiMo Cr (1.0%~ 1.2% ) 5CrNiMo V 5CrNiMo 55NiCrMoV7 5CrNiMo 5CrMnMo 5CrNiMo Ni ( 400mm) Mn [34]

$45 - - 1 CCT 55NiCrMoV7 [56] 1 55NiCrMoV7 CCT 1 55NiCrMoV7 ( /%) Table1 Compositionof55NiCrMoV7steel(massfraction/%) C Si Mn V P S Cr Mo Ni Fe 0.56 0.22 0.80 0.0840.0060.004 1.12 0.45 1.$

2 CCT 55NiCrMoV7 [56] 1 55NiCrMoV7 CCT 1 55NiCrMoV7 ( /%) Table1 Compositionof55NiCrMoV7steel(massfraction/%) C Si Mn V P S Cr Mo Ni Fe Bal CCT NiCrMoV7 (a) ;(b) ;(c) Fig.1 Thermo-physicalparametersof55NiCrMoV7steel (a)elasticmodulusandpossion sratio;(b)linearthermalexpansionratioandthethermalexpansioncoeficient; (c)specificheatcapacityandthermalconductivity 55NiCrMoV7 Formaster-F CCT ; 0.08 /s 2 Fig NiCrMoV7 CCT MeasuredCCTcurvesof55NiCrMoV7steel ABAQUS C3D8RT 3680mm 864mm 4 C3D4T

46 /2011 11 3 55NiCrMoV7 (a) + ;(b) ;(c) ;(d) Fig.

(a)ferrite+carbide;(b)upperbainite;(c)lowerbainite;(d)martensite 41476 h rad =εσ(t +T )(T 2 +T 2 ) h ; [8] h conv

3 46 / NiCrMoV7 (a) + ;(b) ;(c) ;(d) Fig.3 Typicaltransformationmicrostructureof55NiCrMoV7steelunderdiferentcoolingrateranges (a)ferrite+carbide;(b)upperbainite;(c)lowerbainite;(d)martensite h rad =εσ(t +T )(T 2 +T 2 ) h ; [8] h conv 5 ;h rad [7] ;T T T c ;σ - ;ε [9] 4 Fig.4 Thedimensionandmeshofthedieholder 5 Fig.5 T c=25 : : k GradT +h (T -T c )=0 h =h conv +h rad Heattransfercoeficientsundervarious heattreatmentconditions 6

47 X 6 6 0.05 [10] (a)(c) 1h 6(b)(d) 5h : 50 /h : 20 850 ( 6(a) 1h 830~860 [2] ); 825 15h 6(b) 5h 3 270 200 6(c) 6(d) 3.1 1h 5h ; 6 (a) 1h;(b) 5h;(c) 1h;(d) 5h Fig.

4 47 X [10] (a)(c) 1h 6(b)(d) 5h : 50 /h : ( 6(a) 1h 830~860 [2] ); h 6(b) 5h (c) 6(d) 3.1 1h 5h ; 6 (a) 1h;(b) 5h;(c) 1h;(d) 5h Fig.6 Comparisonoftemperaturefieldonthedieholderunderdiferentcoolingperiods (a)1hoil-cooling;(b)5hoil-cooling;(c)1hwater-cooling;(d)5hwater-cooling 135mm CCT 3h 80 ; 7(a)

48 /2011 11 0.08 /s [11] 7(b) CCT ( ) ( ) 0.1 /s 0.1 /s 0.07 /s CCT 7 135mm (a) ;(b) CCT Fig.

(a)positionoftheselectednodeanditscorrespondingcoolingcurveswithoilandwatercooling;

5 48 / /s [11] 7(b) CCT ( ) ( ) 0.1 /s 0.1 /s 0.07 /s CCT 7 135mm (a) ;(b) CCT Fig.7 Coolingcurvesoftheselectedcentralnodewith135mmbelowtheinnersurfaceofthedieholder (a)positionoftheselectednodeanditscorrespondingcoolingcurveswithoilandwatercooling; (b)coolingcurvesbyoilandwatercoolingandtheircorrespondingpositionsinthecctgraph 200~300MPa 600MPa; 8(b) 3.2 1GPa 5h 8(b) ; 8(a) 8(b) 5h 8(a) ; CCT 5h 5h 8 5h (a) ;(b) Fig.8 Comparisonofstressfieldondieholderafter5hcooling (a)stressfieldbyoil-quenching;(b)stressfieldbywater-quenching

6 49 70mm ABAQUS min R150 R (a) ( ) ( ) 135mm CCT 30min 0.08 /s 9(b) 30min 135mm ( ) ( ) 550 ; 70mm 350 [12] 0.1 /s 30min 9 (a) 135mm CCT ;(b) Fig.9 Comparisonofsimulationresultsondoublequenchingprocessandpreviousprocess (a)correspondingpositionsinthecctcurvesofdoublequenchingandoilquenchingcoolingcurvesofthecentralnode with135mmbelowinnersurface;(b)stressevolutionoftheinnerchamferbydoublequenchingandwaterquenchingprocess 4 (1) (135mm ) 0.1 /s (2) [1]. [M]. : [2]. [M]. : 300MPa (3) 30min 0.08 /s [3] ZHANGZDELAGNESDBERNHART G.Microstructureevo- lutionofhot-worktoolsduringtemperinganddefinitionofaki-

7 50 / neticlawbasedonhardnessmeasurements[j].materialsscience andengineeringa (1-2): national200714(6): [4] ZHANGZPQIY HDELAGNESDetal.Microstructurevari- ation and hardness diminution during low cycle fatigue of 55NiCrMoV7steel[J].JournalofIronandSteelResearchInter- [5] SIMSIRCGURC H.3DFEMsimulationofsteelquenchingand investigationoftheefectofasymmetricgeometry onresidual stressdistribution[j].journalofmaterialsprocessingtechnolo- gy (1-3): [6] LIH PZHAO G QHELF.Finiteelementmethodbasedsimu- lationofstress-strainfieldinthequenchingprocess[j].materials ScienceandEngineeringA (1-2): [7] HIBBITT.ABAQUS/Standards User s ManualVersion6.9 [M].New York:Karlsson & SorensenInc2009. [8] ESIGROUP.SYSWELD User s ManualVersion2008[M] [9] P P L. [M]. : [10]. [J] (12): DP)steel[J].MaterialsScienceandEngineeringA (1-2): [11] BAKHTIARIREKRAMIA.Theefectofbainitemorphology onthemechanicalpropertiesofahighbainitedualphase (HB- [12] LEESJPARKJSLEE Y K.Efectofaustenitegrainsizeon thetransformationkineticsofupperandlowbainiteinalow-al- loysteel[j].scriptamaterialia200859(1): : ; : : (1985-) : 72 (110016) mtfan@imr.ac.cn : (1980 ) : (110016) mysun@imr.ac.cn 櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜櫜 SLIPS SLIPS SLIPS SLIPS ( )

2007年普通高等学校招生全国统一考试

2007年普通高等学校招生全国统一考试高考语文陕西卷试题以及答案解析本试卷分第 Ⅰ 卷 ( 选择题 ) 和第 Ⅱ 卷 1 至 4 页, 第 Ⅱ 卷 5 至 8 页考试结束后, 将本试卷和答题卡一并交回第 Ⅰ 卷注意事项 : 1. 答题前, 考生在答题卡上务必用直径 0.5 毫米黑色墨水签字笔将自己的姓