Al对稀土处理C-Mn钢连续冷却组织转变的影响
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摘要
研究Al预脱氧对Ce处理钢夹杂物和显微组织的影响,利用热力学计算、带能谱的扫描电镜和DIL805A热膨胀仪检测进行了对比研究。得到如下结论:Ce处理后钢中的主要夹杂物从MnS转变为Ce2O2S+MnS,Al脱氧能使Ce处理钢中夹杂物转变为CeAlO3+Ce2S3+MnS。Ce处理C-Mn钢连续冷却过程有利于获得晶内铁素体的冷速为2~8℃/s。Al脱氧能改变诱导晶内铁素体形核的核心夹杂物种类,诱导铁素体形核的能力降低,且Al能够使Ce处理钢连续冷却组织转变(CCT)曲线向左上方移动,促进铁素体在晶界形核,不利于Ce处理后晶内铁素体的形成。Al脱氧Ce处理C-Mn钢在冷速为2~5℃/s时,由于夹杂物核心成分的改变与Al合金化作用导致晶内铁素体含量较未用Al脱氧Ce处理钢少。
To make clear the effect of aluminum pre-deoxidization on inclusion formation and microstructure variation in the rare earth Ce treated C-Mn steel,the thermodynamic calculation,scanning electron microscope(SEM)with energy dispersive spectrometer(EDS),and thermal expansion instrument DIL805 A were used.The results show that the main inclusions in steel changed from MnS to Ce2O2S+MnS after rare earth treatment,aluminum deoxidation technology can make the inclusions in rare earth treated steel into CeAlO3+Ce2S3+MnS.It is helpful to obtain the intragranular ferrite at the cold speed of 2-8℃/s in rare earth treated C-Mn steel during continuous cooling process.The aluminum deoxidation technology changes the composition of the nucleus which can induced intragranular ferrite nucleation,as the ability to induce intragranular ferrite decreased.In addition,aluminum can make the continuous cooling transformation curve(CCT curve)of C-Mn steel treated by rare earth move to the left upper side,which enhanced ferrite nucleation at the grain boundary,not conducive to the formation of intragranular ferrite.The content of intragranular ferrite formed in aluminum deoxidizing rare earth treated C-Mn steel is less than that of not Al-deoxidized one as the result of composition changed of nucleus and adverse effect of Al alloying when the cooling speed is 2-5℃/s.
To make clear the effect of aluminum pre-deoxidization on inclusion formation and microstructure variation in the rare earth Ce treated C-Mn steel,the thermodynamic calculation,scanning electron microscope(SEM)with energy dispersive spectrometer(EDS),and thermal expansion instrument DIL805 A were used.The results show that the main inclusions in steel changed from MnS to Ce2O2S+MnS after rare earth treatment,aluminum deoxidation technology can make the inclusions in rare earth treated steel into CeAlO3+Ce2S3+MnS.It is helpful to obtain the intragranular ferrite at the cold speed of 2-8℃/s in rare earth treated C-Mn steel during continuous cooling process.The aluminum deoxidation technology changes the composition of the nucleus which can induced intragranular ferrite nucleation,as the ability to induce intragranular ferrite decreased.In addition,aluminum can make the continuous cooling transformation curve(CCT curve)of C-Mn steel treated by rare earth move to the left upper side,which enhanced ferrite nucleation at the grain boundary,not conducive to the formation of intragranular ferrite.The content of intragranular ferrite formed in aluminum deoxidizing rare earth treated C-Mn steel is less than that of not Al-deoxidized one as the result of composition changed of nucleus and adverse effect of Al alloying when the cooling speed is 2-5℃/s.
引文
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[12]宋明明,宋波,胡春林,等.Ti-Mg复合脱氧对钢热影响区组织和冲击性能的影响[J].工程科学学报,2015,37(7):883.(Song M M,Song B,Hu C L,et al.Effect of Ti-Mg complex deoxidation on the microstructure and impact properties of HAZ in steel[J].Chinese Journal of Engineering,2015,37(7):883.)
[13]Song M M,Song B,Xin W B,et al.Effects of rare earth addition on microstructure of C-Mn steel[J].Ironmaking and Steelmaking,2015,42(8):594.
[14]Thewlis G.Effect of cerium sulphide particle dispersions on acicular ferrite microstructure development in steels[J].Materials Science and Technology,2006,22(2):153.
[15]Wen B,Song B.In situ observation of the evolution of intragranular acicular ferrite at Ce-containing inclusions in 16Mn steel[J].Steel Research International,2012,83(5):487.
[16]Wen B,Song B,Pan N,et al.Effect of austenitizing temperature on microstructure in 16Mn steel treated by cerium[J].International Journal of Minerals,Metallurgy,and Materials,2011,18(6):652.
[17]Wen B,Song B,Pan N,et al.Influence of Ce on characteristics of inclusions and microstructure of pure iron[J].Journal of Iron and Steel Research International,2011,18(2):38.
[2]熊玲琪,李红卫.高强度低合金钢焊缝金属的组织及其影响因素[J].钢铁研究学报,2010,22(6):53.(Xiong L Q,Li H W.Microstructure and influence factor of weld metal for high strength low alloy steel[J].Journal of Iron and Steel Research,2010,22(6):53.)
[3]Suzuki S,Ichimiya K,Akita T.High tensile strength steel plates with excellent HAZ toughness for shipbuilding:JFE EWEL technology for excellent quality in HAZ of high heat input welded joints[J].JFE Technical Report,2005(5):24.
[4]李小宝,张宇,潘鑫.大线能量焊接船板EH40电渣焊接头组织和性能[J].钢铁研究学报,2013,25(9):52.(Li X B,Zhang Y,Pan X.Microstructure and mechanical properties of electro-slag welds of shipbuilding steel plate EH40[J].Journal of Iron and Steel Research,2013,25(9):52.)
[5]Nako H,Okazaki Y,Speer J G.Acicular ferrite formation on Ti-rare earth metal-Zr complex oxides[J].ISIJ International,2015,55(1):250.
[6]Ma W,Bao Y,Wang M,et al.Effect of Mg and Ca treatment on behavior and particle size of inclusions in bearing steels[J].ISIJ International,2014,54(3):536.
[7]Zheng W,Wu Z,Li G,et al.Effect of Al content on the characteristics of inclusions in Al-Ti complex deoxidized steel with calcium treatment[J].ISIJ International,2014,54(8):1755.
[8]Kang Y,Jang J,Park J H,et al.Influence of Ti on non-metallic inclusion formation and acicular ferrite nucleation in highstrength low-alloy steel weld metals[J].Metals and Materials International,2014,20(1):119.
[9]Shim J H,Cho Y W,Shim J D,et al.Effects of Si and Al on acicular ferrite formation in C-Mn steel[J].Metallurgical and Materials Transactions,2001,32A(1):75.
[10]Lee J L.Evaluation of the nucleation potential of intragranular acicular ferrite in steel weldments[J].Acta Metallurgica et Materialia,1994,42(10):3291.
[11]Barbaro F J,Krauklis P,Easterling K E.Formation of acicular ferrite at oxide particles in steels[J].Materials Science and Technology,1989,5(11):1057.
[12]宋明明,宋波,胡春林,等.Ti-Mg复合脱氧对钢热影响区组织和冲击性能的影响[J].工程科学学报,2015,37(7):883.(Song M M,Song B,Hu C L,et al.Effect of Ti-Mg complex deoxidation on the microstructure and impact properties of HAZ in steel[J].Chinese Journal of Engineering,2015,37(7):883.)
[13]Song M M,Song B,Xin W B,et al.Effects of rare earth addition on microstructure of C-Mn steel[J].Ironmaking and Steelmaking,2015,42(8):594.
[14]Thewlis G.Effect of cerium sulphide particle dispersions on acicular ferrite microstructure development in steels[J].Materials Science and Technology,2006,22(2):153.
[15]Wen B,Song B.In situ observation of the evolution of intragranular acicular ferrite at Ce-containing inclusions in 16Mn steel[J].Steel Research International,2012,83(5):487.
[16]Wen B,Song B,Pan N,et al.Effect of austenitizing temperature on microstructure in 16Mn steel treated by cerium[J].International Journal of Minerals,Metallurgy,and Materials,2011,18(6):652.
[17]Wen B,Song B,Pan N,et al.Influence of Ce on characteristics of inclusions and microstructure of pure iron[J].Journal of Iron and Steel Research International,2011,18(2):38.