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1112222(1.,100083;2.,411101),。,;,,。TF777.2ATWOIMPORTANTFACTORSINFLUENCINGQUALITYOFCOLDHEADINGSTEELATXIANGTANSTEELHEQianjin1,PANJinhuan1,JIANGJunpu1,YINZhiqiang2,WANGMingbin2,TIANShusheng2,LINGuoqing2(1.SchoolofMetallurgicalandEcologicalEngineering,UniversityofScienceandTechnologyBeijing,Beijing100083;2.TechnologyDevelopmentCenter,XiangtanIronandSteelGroupCo.,Xiangtan411101)ABSTRACTBasedonlaboratorystudyandthecoldheadingsteelproductionpracticeatXiangtanSteel,twodetrimentalfactorsonthequalityofcoldheadingsteelwereinvestigated.Moldfluxentrapmentduringthebilletcastinggivessomemacro-andlargemicro-inclusionstoruinthecontinuityofthesteel.Theinhomogeneouscoolingduringwirerodrollingmakesabigdifferenceingrainsizedistributionintherodtocauseun-uniformmechanicalproperties.Thesearethetwoimportantfactorstocausecrackingduringthecoldheadingtest.KEYWORDScoldheadingsteel,moldfluxentrapment,inhomogeneouscooling,crackingduringcoldheading1,。1997,:-80t--LF---。。。23,:2003-04-08:,,jjp1504@yahoo.com.cn1φ14mm(1(a))、(1(b))45º(1(c))。。45º。,、;。32,。1SWRCH35KFig.1CracksinwirerodofSWRCH35KgradesteelduringcoldheadingNa2O,。1。,2001SWRCH35K,3(a)(1500µm),3(b)。。,。,。,2Fig.2SEMphotoofrootpointofthecrackparallelwithrollingdirection(%):Na2O4.50,MgO3.32,Al2O313.90,SiO240.0,CaO31.82,MnO1.89,FeO4.55,1Table1CompositionofthemoldfluxatXiangtanSteel%SiO2Al2O3Fe2O3CaOMgOK2O+Na2OFCH2OLiO2336.011.9130.003.927.234.915.020.121.20312(a)(b)Fig.3SEMphotoofsampleNo.12showingslagentrapedincrosssection(a)andtheopticalphotoofsurfacecrackingofthesamesample(b)·22·39。,,,,,。,,,。、,、、,[1]。、,、,。、。,。,。,。,。4,,()。SWRCH10K,4。3～4µm;50～60µm。、HV2。2SWRCH10K、HVTable2Micro-hardness(HV)offineandcoarsegrainsofSWRCH10Kgradewirerod12345218.9153.5127.4145.0156.7160.331.02104.898.292.1114.0110.3103.887.944SWRCH10KFig.4MicrostructureofSWRCH10Kgradewirerod10µm2,50%。[2],。。,。,,。2,、。,、,,,。45º,1(c)45º。。,,,。,。5(31)·32·2:3Fig.3Displacementofthecenterlineofrailheadinrelationtothecenterlineofrailbody,。,。。,。,,,。,,。,。,,,。。,,。5(1),,。,,。(2),,。。,,±0.02mm。。,。(3),。,。。,,,1～2。1LIWei.TechnologyofCloseToleranceRollingofHeavyRailSteel.IronSteelVanadiumTitanium,1995,16(3):73～76.(..,1995,16(3):73～76.)2..,1993,34(384):69～74.3,.CAMP-ISIJ,2000,(13):276～280.4.··.:\]^,1991.104～108.5_HA‘Sheping.ApplicationandDevelopmentofonlineDimensionalMeasurementandControlTechnology.WorldIronaSteel,2002,2(1):14.(..,2002,2(1):14.)6_H‘bcTingdhen.TheoryandPracticeofShortStressPathRollingMill.eeifing:MetallurgicalIndustryPress,1998.12.(..2.:gggggggggggggggggggggggggggggggggggggggggggggggggg,1998.12.)(23)(1)。(2)。1LhIHong,_HiMiaoyong,HhJicheng.MathematicalModelofMoldFlujhntrapment.ActaMetallurgicaSinica,2000,(10):1113～1117.2WiRuijiang.StudyonChiefFactorshffectingthekualityofColdForgingSteelandItskualityControl.HunanMetallurgy,2002,(2):22～24.·lm·1: