國內汽機車活塞銷業者為降低製造成本，已開始採用連續冷鍛方式取

－34－九十七年三月耐滲碳粗晶冷鍛用低合金鋼之開發*DevelopmentofAnti-Grain-CoarseningLowalloySteelforcoldforgingUse*12D.H.Tsai1M.C.Huang2SCr420SCM420Si,MnAlNbTiB920關鍵詞：Continuouscoldforgingprocesshasbeengraduallyadoptedformass-productionofpistonpinswithSCr420orSCM420lowalloysteel.Theadvantagesofcontinuouscoldforgingprocessare(1)iteliminatestheneedofsoftannealingthatincreasedtheproductioncostand(2)itminimizesthegraincoarseningthatdeterioratedthebrokenloadsoftheparts.ThisresearchdevelopedanewlowalloydesignofTi,BandNb,BaddedsteelsbyadjustingSi,MncontentsandaddingAlNbTiBmicroelements.Thenewlowalloysteelsincreasethegraincoarseningtemperatureover920andoptimizethehotrollingprocessofthesteelstocutdowntheproductioncost.KeyWords:PinningEffect,Grain-coarseningCurves,Anti-Grain-Coarsening,andSoftannealing壹、前　言SCM420SCr420(1)900-9406-7*Paperpresentedat2007CIMMEAnnualConvention,October26th,2007,Kaohsiung.121AssociateScientist,SteelandAluminumR&DDept.2Superintendent,BarMill,RollingMill-Department1,ChinaSteelCorporation.－35－鑛冶52/1(2)(3):(4)AlSCr420SCM420(5)Al,Nb,Ti,B-1(wt-%)(1)CSIMNPSCRTiALNBBCr200.20.060.490.010.0080.97-0.045--Cr20B0.20.060.490.010.0080.97-0.043-Cr20NB0.20.060.490.010.0080.97-0.043Cr20TNB0.20.060.490.010.0080.980.042SCr200.20.230.740.010.0071.04-0.04--SCr20T0.20.230.740.010.0071.060.04--SCr20TB0.20.230.740.010.0071.040.04-SCr20TNB0.20.230.740.010.0071.050.04(2)SCr420NbBPistonPinCSIMNPSCRTiALNBBMoCM420Nb0.20.230.760.020.0081.1-0.052-0.230Cr420TiB0.20.010.80.020.011.10.04--Cr420NbB0.20.010.80.020.011.2-0.04-貳、試驗方法2.1試料成份()JISG4105SCr420200100mm100mm50(1)Si,Mn0.06%Si-0.49%Mn-0.97%CrSCr4201Cr20B,Nb,TiCr20BCr20NbBCr20TNB(2)Si,Mn0.23%Si-0.74%Mn-1.04%CrSCr4201SCr20Ti,B,NbSCr20TSCr20TBSCr20TNB19mm8mmx12mm－36－九十七年三月()200CM420NbCr420TiBCr420NbB42mm2.2滲碳實驗9406840101mmThemeanlinearinterceptmethod(6)2.3滲碳晶粒粗化試驗Gleeble1500840-1040584010TEMEDSGrainsizeconversiontable(7)56.6μm2.4常溫衝擊韌試驗JISG4105(8)92510min.8758min.18030min.JISZ220242mmU(9)JISZ2242Charpy(10)2.5動態CCT曲線試驗FP3mm6mmlDilatometerCCT1000585020%78060.130/sSEM&OMHvSCr420CCT2.6熱加工模擬試驗++95011008509507808500.3/sSEMOMHvSCr420－37－鑛冶52/12.7抗壓韌性（壓壞值）及滲碳硬化深度試驗920785030min.1902JISG0557(11)MTS參、結果與討論3.1冷鍛促進滲碳粗晶之冶金機制-120%40Al,Nb,BAl40(5)70%75AlNAlNPinningEffect920SCr420Nb,B108020%1040Nb(C,N)AlN+Nb(C,N)3.2微合金添加對抑制滲碳粗晶之影響20-70ppm110-170ppmAl,Nb,Ti,BAlNNb(C,N)Ti(C,N)(12)845ppm-13.2.1Al系或Al,B系：AlCr20,Cr20B0.045%Al0.0045%N880920-2SCM420975.0036%Al-.0167%NCuddy(13)(Tc)Tc3850.535{6770/(1.03log[Al][N])273}AlN920-1Nb,B－38－九十七年三月AlNOstwaldRipeningAlN(13)AlNAlTi,Nb,B3.2.2Ti系或Ti,B系：TiSCr20TAlSCr20880920Ti,BSCr20TB1040-31080-4TiCN10401080TiCNBTi,BTiCNBTiSCr20TBCr20B8803.2.3Nb系或Nb,B系：NbSCM420Nb1040Nb,BCr20NB1080-2-4NbCNAlN10401080NbCN+AlNNb,BTi,B40-2Al,B-3Ti,Nb,B-4Ti,BNb,BTEM－39－鑛冶52/13.3微合金添加對滲碳衝擊韌性之影響3.3.1Al系或Al,B系：-5AlSCr4200.043%Al7.9J/cm2BAl,B8.2J/cm2Al2.9%AlSCr420BTi,B3.3.2Ti系或Ti,B系：-6Ti,AlSCr20T0.022%Ti-0.044%Al9.1J/cm2AlSCr42015.1%Ti3.42N0.015%TiTi,BSCr20TB10.4J/cm231.1%TiB(14)3.3.3Nb系或Nb,B系：Al,NbSCM420Nb0.02%NbAlSCM4204.9%(15)Al,Nb,BCr20NBNb,BAlSCr42011.8%AlBNbTiTiBNbTi15.1%5%Nb,BTi,B11.8%31.1%Ti,B31.1%Ti,BSCr20TB(31%)TiSCr20T(15%)Nb,BCr20NB(11%)Nb(5%)Al,B(3%)Al3.4.省略軟化退火之軋延條件最適化評估3.4.1動態CCT曲線FPCCTSCr420-5Ti,Nb,B-6Ti,B－40－九十七年三月1000850780-1/sHv168-7NbSCr4200.1/sF+PHv192(16)NbSCr420FPNb3.4.2軋延條件最適化(1)Ti,B0.3/sSCr420TB10009508500.3/sHv153.5HRB80SCr420-8FPSCr420Hv140HRB750.05/s(17)(2)Nb,BCr20NB1000Hv142.1(HRB75.8)SCr420-91000Nb(C,N)Nb3.4.3現場實際軋延結果(1)(17)SCr420HRB84FPHRB75-7SCr420CCT-8TiB-9NbB－41－鑛冶52/1(2)42mm-10Nb,BSCr420NbBHRB87.1NbSCM420NbHRB96.2Hv227Ti,BSCr420TiBHRB81Hv158SCr420Hv168HRB84FPHRB803.5二次加工及客戶試製結果3.5.1二次加工42mm37.8mm(1)-10SCM420NbSCr420NbBSCr420SCM420NbNb,BSCr420NbBSCr420TiBSi,MnHRB81(Hv158)SCr420(HRB84)(2)-11Nb,BSCr420NbBTi,BSCr420TiBSCr420Nb,BSCr420NbBHRB74.8Nb,BTi,BSi,MnSCr420(3)-10NbB-11NbB－42－九十七年三月40mmTi,BSCr420-123.5.2客戶試製結果(1)-13920x7hrsNbSCM420NbTi,BSCr420TiBNb,BSCr420NbB7.76.97.2(2)-14SCM415H0.92mmNbSCM420Nb6.4%Nb,BSCr420NbB9.6%Ti,BSCr420TiB14.9%Nb,BTi,BSCr420SCM415H(3)SCr420SCM415H-15Nb,BSCr420NbBTi,BSCr420TiBSCM415H17.5%SCM415H-12-13Ti,Nb,B-14Ti,Nb,B-15－43－鑛冶52/1肆、結　論AlNbTiBPinningEffectAl1.冷鍛後滲碳粗晶機制之澄清：20%40AlNAlNPinningEffect920SCr4202.耐冷鍛後滲碳粗晶特性之提升：Ti,BNb1040Nb,BTi,Nb,B10801040NbCNAlNTi,Nb,BNb,BTi,B403.微合金添加對滲碳衝擊韌性之提升：Ti,BNb,BAlSCr2011%Nb,BTi,BSCM415H17.5%SCM415H4.省略軟化退火之軋延條件最適化：Ti,B10000.3/sHv152.5HRB79.5伍、參考文獻坽11-236646(1999),8,31夌65(1994),p.67奅48(1999),p.41妵59(1973)p.1124妺TE92015,(2004),pp.1-11姏R.K.AminandP.B.Pickering:Conf.Proceed.OnThermomechanicalProcessingofMicroalloyedAustenite,AIME,editedbyA.J.DeArdoetc.,Pittsburgh,Aug.(1981),pp.1-30.姎A.J.DeArdoetc:Conf.Proceed.OnThermomechanicalProcessingofMicroalloyedAustenite,AIME,Pittsburgh,Aug.(1981).妲JISHandbookG4105(1981),p.863.姌JISHandbookZ2202(1981),p.30.姁JISHandbookZ2242(1981),p.38-40.妶JISHandbookG0557(1981),p.194-195.妼L.J.CuddyandJ.C.Raley:Metall.Trans.A,14A(1983),pp.1989-1995姃T.Gladman:ThePhysicalMetallurgyofMicroalloyedSteels,TheInstituteofMaterials,(1997),pp.201-210姖MaterialJapan37(1998)6