Effect of slag on oxide inclusions in carburized bearing steel during industrial electroslag remelting
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摘要
Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage~(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.
Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage~(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.
Industrial experiments with three types of slags were performed to investigate the effect of slag on oxide inclusions during electroslag remelting(ESR) process. G20CrNi2Mo bearing steel was used as the consumable electrode and remelted using a 2400-kg industrial furnace. The results showed that most inclusions in the electrode were low-melting-point CaO-MgO-Al_2O_3. After ESR, all the inclusions in ingots were located outside the liquid region. When the slag consisted of 65.70 wt% CaF_2, 28.58 wt% Al_2O_3, and 4.42 wt% CaO was used, pure Al_2O_3 were the dominant inclusions in ingot, some of which presented a clear trend of agglomeration. When the ingot was remelted by a multi-component slag with 16.83 wt% CaO, a certain amount of sphere CaAl_4O_7 inclusions larger than 5 μm were generated in ingot. The slag with 8.18 wt% CaO exhibited greater capacity to control the inclusion characteristics. Thermodynamic calculations indicated that the total Ca and Mg in ingots were attributed from the relics in electrode and strongly influenced by the slag composition. The formation of ingot inclusions was calculated by FactSage~(TM) 7.0, and the results were basically in accordance with the observed inclusions, indicating that a quasi-thermodynamic equilibrium could be obtained in the metal pool.
引文
[1]K.Namiki and K.Isokawa,Effects of alloying elements on the rotating bending fatigue properties of carburized steels,Trans.Iron Steel Inst.Jpn.,26(1986),No.7,p.642.
[2]H.Suito and R.Inoue,Thermodynamics on control of inclusions composition in ultra-clean steels,ISIJ Int.,36(1996),No.5,p.528.
[3]M.Nagao,K.Hiraoka,and Y.Unigame,Influence of nonmetallic inclusion size on rolling contact fatigue life in bearing steel,Sanyo Tech.Rep.,12(2005),No.1,p.38.
[4]M.Jiang,X.H.Wang,and W.J.Wang,Control of non-metallic inclusions by slag-metal reactions for high strength alloying steels,Steel Res.Int.,81(2010),No.9,p.759.
[5]X.D.Miu,C.M.Yu,C.M.Shi,J.F.Du,H.G.Zhu and G.G.Cheng,Formation and control of calcium aluminates in bearing steel,J.Univ.Sci.Technol.Beijing,29(2008),No.8,p.771.
[6]V.Weber,A.Jardy,B.Dussoubs,D.Ablitzer,S.Ryberon,V.Schmitt,S.Hans,and H.Poisson,A comprehensive model of the electroslag remelting process:Description and validation,Metall.Mater.Trans.B,40(2009),No.3,p.271.
[7]S.K.Matity,N.B.Ballal,G.Goldhahn,and R.Kwaalla,Development of ultrahigh strength low alloy steel through electroslag refining process,ISIJ Int.,49(2009),No.6,p.902.
[8]Y.W.Dong,Z.H.Jiang,Y.L.Cao,A.Yu,and D.Hou,Effect of slag on inclusions during electroslag remelting process of die steel,Metall.Mater.Trans.B,45(2014),No.4,p.1315.
[9]A.Mitchell,F.R.Carmona,and E.Samuelsson,The deoxidation of low-alloy steel ingots during ESR,Trans.Iron Steel Inst.Jpn.,24(1984),No.7,p.547.
[10]F.Reyes-Carmona and A.Mitchell,Deoxidation of ESRslags,ISIJ Int.,32(1992),No.4,p.529.
[11]S.J.Li,G.G.Cheng,Z.Q.Miao,L.Chen,C.W.Li,and X.Y.Jiang,Kinetic analysis of aluminum and oxygen variation of G20Cr Ni2Mo bearing steel during industrial electroslag remelting process,ISIJ Int.,57(2017),No.12,p.2148.
[12]M.Sasabe and Y.Kinoshita,Permeability of oxygen through molten Ca O-Si O2-Al2O3 system with Fe2O3 or Ca F2,Tetsu-to-Hagane,65(1979),No.12,p.1727.
[13]E.Shibata,H.P.Sun,and K.Mori,Transfer rate of oxygen from gas into liquid iron through molen slag,Tetsu-to-Hagane,85(1999),No.1,p.27.
[14]S.J.Li,G.G.Cheng,L.Yang,L.Chen,Q.Z.Yan,and C.W.Li,A thermodynamic model to design the equilibrium slag compositions during electroslag remelting process:Description and verification,ISIJ Int.,57(2017),No.4,p.713.
[15]K.Riyahimalayeri,P.?lund,and M.Selleby,Effect of vacuum degassing on non-metallic inclusions in an ASEA-SKFladle furnace,Ironmaking Steelmaking,40(2013),No.6,p.470.
[16]H.Yin,H.Shibata,T.Emi,and M.Suzuki,“In-situ”observation of collision,agglomeration and cluster formation of alumina inclusion particles on steel melts,ISIJ Int.,37(1997),No.10,p.936.
[17]Y.Kang,B.Sahebkar,P.R.Scheller,K.Morita,and D.Sichen,Observation on physical growth of nonmetallic inclusion in liquid steel during ladle treatment,Metall.Mater.Trans.B,42(2011),No.3,p.522.
[18]W.Z.Mu,N.Dogan,and K.S.Coley,Agglomeration of non-metallic inclusions at steel/Ar interface:In-situ observation experiments and model validation,Metall.Mater.Trans.B,48(2017),No.5,p.2379.
[19]G.Ye,P.J?nsson,and T.Lund,Thermodynamics and kinetics of the modification of Al2O3 inclusions,ISIJ Int.,36(1996),Suppl.,p.S105.
[20]H.Ohta and H.Suito,Calcium and magnesium deoxidation in Fe-Ni and Fe-Cr alloys equilibrated with CaO-Al2O3 and Ca O-Al2O3-Mg O slags,ISIJ Int.,43(2003),No.9,p.1293.
[21]M.E.Fraser and A.Mitchell,Mass transfer in the electroslag process Pt.1.Mass-transfer model,Ironmaking Steelmaking,3(1976),No.5,p.279.
[22]A.Mitchell,J.Szekely,and J.F.Elliott,Electroslag Refining,Iron and Steel Institute,London,1973,p.25.
[23]L.Yang and G.G.Cheng,Characteristics of Al2O3,MnS,and Ti N inclusions in the remelting process of bearing steel,Int.J.Miner.Metall.Mater.,24(2017),No.8,p.869.
[24]Z.B.Li,Electroslag Metallurgy Theory and Practice,Metallurgical Industry Press,Beijing,2010.
[25]The Japan Society for the Promotion of Science,The 19th Committee on Steelmaking Data Sourcebook,Gordon and Breach Science Pub.,New York,1988,p.45.
[26]L.F.Zhang,Y.Ren,H.J.Duan,W.Yang,and L.Y.Sun,Stability diagram of Mg-Al-O system inclusions in molten steel,Metall.Mater.Trans.B,46(2015),No.4,p.1809.
[27]J.Zhang,Calculated Thermodynamics of Metallurgical Melts and Solution,Metallurgical Industry Press,Beijing,2007.
[28]J.Fu,An investigation of mechanism on the removal of oxide inclusions during ESR process,Acta Metall.Sin.,15(1979),No.4,p.526.
[29]K.Ogino,S.Hara,T.Miwa,and S.Kimoto,The effect of oxygen content in molten steel on the interfacial tension between molten steel and slag,Tetsu-to-Hagane,65(1979),No.14,p.2012.
[30]J.Wikstr?m,K.Nakajima,H.Shibata,A.Tilliander and P.J?nsson,In situ studies of agglomeration between Al2O3-Ca O inclusions at metal/gas,metal/slag interfaces and in slag,Ironmaking Steelmaking,35(2008),No.8,p.589.
[31]B.H.Reis,W.V.Bielefeldt,and A.C.F.Vilela,Efficiency of inclusion absorption by slags during secondary refining of steel,ISIJ Int.,54(2014),No.7,p.1584.
[32]A.Mitchell,Oxide inclusion behavior during consumable electrode remelting,Ironmaking Steelmaking,1(1974),No.3,p.172.
[2]H.Suito and R.Inoue,Thermodynamics on control of inclusions composition in ultra-clean steels,ISIJ Int.,36(1996),No.5,p.528.
[3]M.Nagao,K.Hiraoka,and Y.Unigame,Influence of nonmetallic inclusion size on rolling contact fatigue life in bearing steel,Sanyo Tech.Rep.,12(2005),No.1,p.38.
[4]M.Jiang,X.H.Wang,and W.J.Wang,Control of non-metallic inclusions by slag-metal reactions for high strength alloying steels,Steel Res.Int.,81(2010),No.9,p.759.
[5]X.D.Miu,C.M.Yu,C.M.Shi,J.F.Du,H.G.Zhu and G.G.Cheng,Formation and control of calcium aluminates in bearing steel,J.Univ.Sci.Technol.Beijing,29(2008),No.8,p.771.
[6]V.Weber,A.Jardy,B.Dussoubs,D.Ablitzer,S.Ryberon,V.Schmitt,S.Hans,and H.Poisson,A comprehensive model of the electroslag remelting process:Description and validation,Metall.Mater.Trans.B,40(2009),No.3,p.271.
[7]S.K.Matity,N.B.Ballal,G.Goldhahn,and R.Kwaalla,Development of ultrahigh strength low alloy steel through electroslag refining process,ISIJ Int.,49(2009),No.6,p.902.
[8]Y.W.Dong,Z.H.Jiang,Y.L.Cao,A.Yu,and D.Hou,Effect of slag on inclusions during electroslag remelting process of die steel,Metall.Mater.Trans.B,45(2014),No.4,p.1315.
[9]A.Mitchell,F.R.Carmona,and E.Samuelsson,The deoxidation of low-alloy steel ingots during ESR,Trans.Iron Steel Inst.Jpn.,24(1984),No.7,p.547.
[10]F.Reyes-Carmona and A.Mitchell,Deoxidation of ESRslags,ISIJ Int.,32(1992),No.4,p.529.
[11]S.J.Li,G.G.Cheng,Z.Q.Miao,L.Chen,C.W.Li,and X.Y.Jiang,Kinetic analysis of aluminum and oxygen variation of G20Cr Ni2Mo bearing steel during industrial electroslag remelting process,ISIJ Int.,57(2017),No.12,p.2148.
[12]M.Sasabe and Y.Kinoshita,Permeability of oxygen through molten Ca O-Si O2-Al2O3 system with Fe2O3 or Ca F2,Tetsu-to-Hagane,65(1979),No.12,p.1727.
[13]E.Shibata,H.P.Sun,and K.Mori,Transfer rate of oxygen from gas into liquid iron through molen slag,Tetsu-to-Hagane,85(1999),No.1,p.27.
[14]S.J.Li,G.G.Cheng,L.Yang,L.Chen,Q.Z.Yan,and C.W.Li,A thermodynamic model to design the equilibrium slag compositions during electroslag remelting process:Description and verification,ISIJ Int.,57(2017),No.4,p.713.
[15]K.Riyahimalayeri,P.?lund,and M.Selleby,Effect of vacuum degassing on non-metallic inclusions in an ASEA-SKFladle furnace,Ironmaking Steelmaking,40(2013),No.6,p.470.
[16]H.Yin,H.Shibata,T.Emi,and M.Suzuki,“In-situ”observation of collision,agglomeration and cluster formation of alumina inclusion particles on steel melts,ISIJ Int.,37(1997),No.10,p.936.
[17]Y.Kang,B.Sahebkar,P.R.Scheller,K.Morita,and D.Sichen,Observation on physical growth of nonmetallic inclusion in liquid steel during ladle treatment,Metall.Mater.Trans.B,42(2011),No.3,p.522.
[18]W.Z.Mu,N.Dogan,and K.S.Coley,Agglomeration of non-metallic inclusions at steel/Ar interface:In-situ observation experiments and model validation,Metall.Mater.Trans.B,48(2017),No.5,p.2379.
[19]G.Ye,P.J?nsson,and T.Lund,Thermodynamics and kinetics of the modification of Al2O3 inclusions,ISIJ Int.,36(1996),Suppl.,p.S105.
[20]H.Ohta and H.Suito,Calcium and magnesium deoxidation in Fe-Ni and Fe-Cr alloys equilibrated with CaO-Al2O3 and Ca O-Al2O3-Mg O slags,ISIJ Int.,43(2003),No.9,p.1293.
[21]M.E.Fraser and A.Mitchell,Mass transfer in the electroslag process Pt.1.Mass-transfer model,Ironmaking Steelmaking,3(1976),No.5,p.279.
[22]A.Mitchell,J.Szekely,and J.F.Elliott,Electroslag Refining,Iron and Steel Institute,London,1973,p.25.
[23]L.Yang and G.G.Cheng,Characteristics of Al2O3,MnS,and Ti N inclusions in the remelting process of bearing steel,Int.J.Miner.Metall.Mater.,24(2017),No.8,p.869.
[24]Z.B.Li,Electroslag Metallurgy Theory and Practice,Metallurgical Industry Press,Beijing,2010.
[25]The Japan Society for the Promotion of Science,The 19th Committee on Steelmaking Data Sourcebook,Gordon and Breach Science Pub.,New York,1988,p.45.
[26]L.F.Zhang,Y.Ren,H.J.Duan,W.Yang,and L.Y.Sun,Stability diagram of Mg-Al-O system inclusions in molten steel,Metall.Mater.Trans.B,46(2015),No.4,p.1809.
[27]J.Zhang,Calculated Thermodynamics of Metallurgical Melts and Solution,Metallurgical Industry Press,Beijing,2007.
[28]J.Fu,An investigation of mechanism on the removal of oxide inclusions during ESR process,Acta Metall.Sin.,15(1979),No.4,p.526.
[29]K.Ogino,S.Hara,T.Miwa,and S.Kimoto,The effect of oxygen content in molten steel on the interfacial tension between molten steel and slag,Tetsu-to-Hagane,65(1979),No.14,p.2012.
[30]J.Wikstr?m,K.Nakajima,H.Shibata,A.Tilliander and P.J?nsson,In situ studies of agglomeration between Al2O3-Ca O inclusions at metal/gas,metal/slag interfaces and in slag,Ironmaking Steelmaking,35(2008),No.8,p.589.
[31]B.H.Reis,W.V.Bielefeldt,and A.C.F.Vilela,Efficiency of inclusion absorption by slags during secondary refining of steel,ISIJ Int.,54(2014),No.7,p.1584.
[32]A.Mitchell,Oxide inclusion behavior during consumable electrode remelting,Ironmaking Steelmaking,1(1974),No.3,p.172.