Evolution of oxide–CaS complex inclusions during protective atmosphere electroslag remelting

LIU Wei-jian; SHI Cheng-bin; XU Hao-chi; ZHENG Ding-li; Lü Shi-gang; LI Jing; GUO Bao-shan

doi:10.13374/j.issn2095-9389.2020.03.12.s08

Volume 42 Issue S

Dec. 2020

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LIU Wei-jian, SHI Cheng-bin, XU Hao-chi, ZHENG Ding-li, Lü Shi-gang, LI Jing, GUO Bao-shan. Evolution of oxide–CaS complex inclusions during protective atmosphere electroslag remelting[J]. Chinese Journal of Engineering, 2020, 42(S): 109-118. doi: 10.13374/j.issn2095-9389.2020.03.12.s08

Citation:

LIU Wei-jian, SHI Cheng-bin, XU Hao-chi, ZHENG Ding-li, Lü Shi-gang, LI Jing, GUO Bao-shan. Evolution of oxide–CaS complex inclusions during protective atmosphere electroslag remelting[J]. Chinese Journal of Engineering, 2020, 42(S): 109-118. doi: 10.13374/j.issn2095-9389.2020.03.12.s08

Citation:

LIU Wei-jian, SHI Cheng-bin, XU Hao-chi, ZHENG Ding-li, Lü Shi-gang, LI Jing, GUO Bao-shan. Evolution of oxide–CaS complex inclusions during protective atmosphere electroslag remelting[J]. Chinese Journal of Engineering, 2020, 42(S): 109-118. doi: 10.13374/j.issn2095-9389.2020.03.12.s08

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Evolution of oxide–CaS complex inclusions during protective atmosphere electroslag remelting

doi: 10.13374/j.issn2095-9389.2020.03.12.s08

1.
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
2.
Xingtai Iron and Steel Co., Ltd., Xingtai 054027, China

More Information

Corresponding author: E-mail: chengbin.shi@ustb.edu.cn
Received Date: 2020-03-12
Publish Date: 2020-12-25

Abstract

Abstract

The inclusions in the consumable steel electrode and electroslag remelted steel were characterized using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS). The evolution mechanism of oxide–sulfide complex inclusions during electroslag remelting (ESR) was elucidated based on inclusion experimental identification and thermodynamic calculation. The results show that the combination of protective atmosphere and deoxidation operation during ESR lowers the total oxygen content from 0.0017% in the electrode to 0.0008% in the ingot. The number proportion of the inclusions smaller than 3 μm in the steel greatly increases after ESR. The inclusions in the steel electrode are two oxide–sulfide complex types of CaS+CaO–Al₂O₃–SiO₂–MgO containing about 3% MgO and CaS+CaO–Al₂O₃–SiO₂–MgO containing about 11% MgO. SiO₂ in the original oxide inclusions that had not been removed in ESRR process was reduced by soluble aluminum in liquid steel, and the products remain in the ESR process until in remelted ingot. The CaO–Al₂O₃–SiO₂–MgO inclusions with uniform elements distribution, which contain about 1%MgO and about 2%SiO₂, in the ingot are newly formed oxide inclusions in the ESR. CaS inclusions in the steel electrode were removed during the ESR through dissociating into soluble calcium and sulfur in liquid steel, and in the way of reacting with Al₂O₃ in liquid oxide inclusions. The shell-type CaS around low-melting-temperature oxide inclusion generated as a result of the reaction between CaO in the oxide inclusion and dissolved aluminum and sulfur in liquid steel during solidification of liquid steel in the ESR process. The shell-type CaS around high-melting-temperature oxide inclusion is the reaction products of enriched soluble Ca and S during solidification of liquid steel. Patch-type CaS in the oxide–sulfide complex inclusion precipitated from the complex inclusion melt during the cooling of liquid steel in the ESR process.
- non-metallic inclusion,
- sulfide,
- electroslag remelting,
- ultralow oxygen,
- sulfide capacity

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References(31)

References

[1]	Shi C B. Deoxidation of electroslag remelting (ESR) — a review. ISIJ Int, 2020, 60(6): 1083 doi: 10.2355/isijinternational.ISIJINT-2019-661
[2]	傅杰, 朱覺. 電渣重熔過程中氧化物夾雜的變化. 金屬學報, 1964, 7(3):250 Fu J, Zhu J. Change in the oxide inclusions during electroslag remelting. Acta Metall Sin, 1964, 7(3): 250
[3]	Kay D A R, Pomfret R J. Removal of oxide inclusions during ac electroslag remelting. J Iron Steel Inst, 1971, 209(12): 962
[4]	Mitchell A. Oxide inclusion behavior during consumable electrode remelting. Ironmaking Steelmaking, 1974, 1(3): 172
[5]	李正邦, 周文輝, 李誼大. 電渣重熔去除夾雜的機理. 鋼鐵, 1980, 15(1):20 Li Z B, Zhou W H, Li Y D. Mechanism of removal of non-metallic inclusions in the ESR process. Iron Steel, 1980, 15(1): 20
[6]	周德光, 陳希春, 傅杰, 等. 電渣重熔與連鑄軸承鋼中的夾雜物. 北京科技大學學報, 2000, 22(1):26 doi: 10.3321/j.issn:1001-053X.2000.01.008 Zhou D G, Chen X C, Fu J, et al. Inclusions in electroslag remelting and continuous casting bearing steels. J Univ Sci Technol Beijing, 2000, 22(1): 26 doi: 10.3321/j.issn:1001-053X.2000.01.008
[7]	Medina S F, Cores A. Thermodynamic aspects in the manufacturing of microalloyed steels by the electroslag remelting process. ISIJ Int, 1993, 33(12): 1244 doi: 10.2355/isijinternational.33.1244
[8]	Mitchell A, Reyes-Carmona F, Samuelsson E. The deoxidation of low-alloy steel ingots during ESR. Trans Iron Steel Inst Jpn, 1984, 24(7): 547 doi: 10.2355/isijinternational1966.24.547
[9]	Dong Y W, Jiang Z H, Cao Y L, et al. Effect of slag on inclusions during electroslag remelting process of die steel. Metall Mater Trans B, 2014, 45(4): 1315 doi: 10.1007/s11663-014-0070-7
[10]	Schneider R S E, Molnar M, Gelder S, et al. Effect of the slag composition and a protective atmosphere on chemical reactions and non-metallic inclusions during electro-slag remelting of a hot-work tool steel. Steel Res Int, 2018, 89(10): 1800161 doi: 10.1002/srin.201800161
[11]	Shi C B, Wang H, Li J. Effects of reoxidation of liquid steel and slag composition on the chemistry evolution of inclusions during electroslag remelting. Metall Mater Trans B, 2018, 49(4): 1675 doi: 10.1007/s11663-018-1296-6
[12]	Shi C B, Yu W T, Wang H, et al. Simultaneous modification of alumina and MgO·Al₂O₃ inclusions by calcium treatment during electroslag remelting of stainless tool steel. Metall Mater Trans B, 2017, 48(1): 146 doi: 10.1007/s11663-016-0771-1
[13]	Shi C B, Chen X C, Guo H J, et al. Assessment of oxygen control and its effect on inclusion characteristics during electroslag remelting of die steel. Steel Res Int, 2012, 83(5): 472 doi: 10.1002/srin.201100200
[14]	Shi C B, Chen X C, Guo H J, et al. Control of MgO·Al₂O₃ spinel inclusions during protective gas electroslag remelting of die steel. Metall Mater Trans B, 2013, 44(2): 378 doi: 10.1007/s11663-012-9780-x
[15]	Shi C B, Zheng D L, Guo B S, et al. Evolution of oxide–sulfide complex inclusions and its correlation with steel cleanliness during electroslag rapid remelting (ESRR) of tool steel. Metall Mater Trans B, 2018, 49(6): 3390 doi: 10.1007/s11663-018-1398-1
[16]	Shi C B, Zhang J X, Zheng X, et al. Review on desulfurization of electroslag remelting (ESR). Int J Miner Metall Mater, 2020 doi: 10.1007/s12613-020-2075-3
[17]	Liu Y, Zhang Z, Li G Q, et al. Evolution of desulfurization and characterization of inclusions in dual alloy ingot processed by electroslag remelting. Steel Res Int, 2017, 88(11): 1700058 doi: 10.1002/srin.201700058
[18]	Li S J, Cheng G G, Miao Z Q, et al. Evolution of oxide Inclusions in G20CrNi2Mo carburized bearing steel during industrial electroslag remelting. ISIJ Int, 2018, 58(10): 1781 doi: 10.2355/isijinternational.ISIJINT-2018-072
[19]	Chang L Z, Shi X F, Cong J Q. Study on mechanism of oxygen increase and countermeasure to control oxygen content during electroslag remelting process. Ironmaking Steelmaking, 2014, 41(3): 182 doi: 10.1179/1743281213Y.0000000114
[20]	Ohta H, Suito H. Activities in CaO–SiO₂–Al₂O₃ slags and deoxidation equilibria of Si and Al. Metall Mater Trans B, 1996, 27(6): 943 doi: 10.1007/s11663-996-0008-9
[21]	Park J H, Lee S B, Kim D S, et al. Thermodynamics of titanium oxide in CaO–SiO₂–Al₂O₃–MgOsatd–CaF₂ slag equilibrated with Fe–11mass%Cr melt. ISIJ Int, 2009, 49(3): 337 doi: 10.2355/isijinternational.49.337
[22]	Park J H, Todoroki H. Control of MgO·Al₂O₃ spinel inclusions in stainless steels. ISIJ Int, 2010, 50(10): 1333 doi: 10.2355/isijinternational.50.1333
[23]	Suito H, Inoue R. Thermodynamics on control of inclusions composition in ultraclean steels. ISIJ Int, 1996, 36(5): 528 doi: 10.2355/isijinternational.36.528
[24]	Sigworth G K, Elliott J F. The thermodynamics of liquid dilute iron alloys. Met Sci, 1974, 8(1): 298 doi: 10.1179/msc.1974.8.1.298
[25]	魏季和, Mitchell A. 交流電渣重熔過程中的成分變化 I. 理論傳質模型. 金屬學報, 1984, 20(5):261 Wei J H, Mitchell A. Changes in composition during A.C. ESR – I. theoretical development. Acta Metall Sin, 1984, 20(5): 261
[26]	史成斌. 氣體保護電渣重熔過程中氧和夾雜物的行為與控制研究[學位論文]. 北京: 北京科技大學, 2012 Shi C B. Behaviour and Control Technique of Oxygen and Inclusions during Protective Gas Electroslag Remelting Process[Dissertation]. Beijing: University of Science and Technology Beijing, 2012
[27]	Fraser M E, Mitchell A. Mass transfer in the electroslag process Pt. 1. Mass-transfer model. Ironmaking Steelmaking, 1976, 3(5): 279
[28]	Mitchell A, Szekely J, Elliott J F. Electroslag Refining. London: The Iron and Steel Institute, 1973
[29]	Ohta H, Suito H. Calcium and magnesium deoxidation in Fe–Ni and Fe–Cr alloys equilibrated with CaO–Al₂O₃ and CaO–Al₂O₃–MgO slags. ISIJ Int, 2003, 43(9): 1293 doi: 10.2355/isijinternational.43.1293
[30]	Fukaya H, Miki T. Phase equilibrium between CaO·Al₂O₃ saturated molten CaO–Al₂O₃–MnO and (Ca, Mn)S solid solution. ISIJ Int, 2011, 51(12): 2007 doi: 10.2355/isijinternational.51.2007
[31]	Nzotta M M, Du S C, Seetharaman S. Sulphide capacities in some multi component slag systems. ISIJ Int, 1998, 38(11): 1170 doi: 10.2355/isijinternational.38.1170