Deoxidation of H13 tool steel with CaF₂-MgO-CaO-Al₂O₃-SiO₂ slags at 1873 K

Abstract

Laboratory-scale experiments were performed to investigate the deoxidation of H13 tool steel with CaF₂-MgO-Al₂O₃-CaO-SiO₂ slags at 1873 K. The calculation of thermodynamics and kinetics was also verified through the experimental results. The results show that [Si]-[O] reaction is the control reaction, and with the increase of basicity of slag, the limitation of deoxidation was decreased. The limitation of deoxidation is the lowest for the slag with basicity of 2.0. Under the conditions of the basicity of 2.0 and the content of CaF₂ more than 50%, the limitation of deoxidation is less than 10 × 10⁻⁶, and it does not depend on the contents of Al₂O₃ and CaF₂ in slags. The mass transport of oxygen in the metal phase is the rate-controlling step, and the slag composition has no effect on the equilibrium time of deoxidation. Based on this finding, the optimized slag composition is designed and it contains the following components: 51.5% CaF₂ 20.3% MgO, 16.2% Al₂O₃, 8.2% CaO and 3.8% SiO₂. In the case of the optimized deoxidizing slag, the total oxygen content in H13 steel can be reduced from 25 × 10⁻⁶ to 6 × 10⁻⁶.

Keywords

deoxidation / H13 tool steel / slag-steel interface reaction / slag optimization

References

[1] ZhangL-F. State-of-the-art in the control of inclusions in tire cord steels–A review [J]. Steel Research International, 2006, 77(3): 158-169

[2] ParkJ H, KangY. Inclusions in stainless steels–A review [J]. Steel Research International, 2017, 88(12): 1700130-1700146

[3] YaoJ, QuX-h, Rafi-ud-din, HeX-b, ZhangL. Effect of inclusion on high cycle fatigue response of a powder metallurgy tool steel [J]. Journal of Central South University, 2012, 19(7): 1773-1779

[4] ShiC-b, ZhengD-l, GuoB-s, LiJ, JiangF. Evolution of oxide-sulfide complex inclusions and its correlation with steel cleanliness during electroslag rapid remelting (ESRR) of tool steel [J]. Metallurgical and Materials Transactions B, 2019, 49(6): 3390-3402

[5] ZhangL-f, ThomasB G, WangX-h, CaiK-K. Evaluation and control of steel cleanliness review [C]. 85th Steelmaking Conference Proceedings, 2002, Warrendale, ISS-AIME, 431452

[6] KatoYSanyo technical report [R], 1995, Himeji, Sanyo Special Steel Co., Ltd.(in Japanese)

[7] HuC-FEffect of oxygen content on fatigue properties of carburized gear steel [D], 2019, Wuhan, Wuhan University of Science and Technology(in Chinese)

[8] XuJ, JiangX-s, ChenZ-z, ChenJ-RTool steel [M], 1998, Beijing, Metallurgical Industry Press(in Chinese)

[9] FU Jie, ZHU Jue. Changes of oxide inclusions during electroslag remelting [J]. Acta Metallurgy Sinica, 1964(7): 250–261. (in Chinese)

[10] ShiC-b, ChenX-c, GuoH-j, ZhuZ-j, RenH. Assessment of oxygen control and its effect on inclusion characteristics during electroslag remelting of die steel [J]. Steel Research International, 2012, 83(5): 472-486

[11] LiuZ-Y. Study on oxygen transfer of slag based on CaF₂+Al₂O₃ and CaF₂+AlO₃+CaO for electroslag remelting [J]. Acta Metallurgy Sinca, 1994, 30(8): 350-359(in Chinese)

[12] ChenX-c, ShiC-b, GuoH-j, WangF, RenH, FengD. Investigation of oxide inclusions and primary carbonitrides in Inconel 718 superalloy refined through electroslag remelting process [J]. Metallurgical and Materials Transactions B, 2012, 43(6): 1596-1607

[13] DuanS-c, ShiX, ZhangM-c, LiB, YangW-s, WangF, GuoH-j, GuoJ. Effect of slag composition on the deoxidation and desulfurization of Inconel 718 superalloy by ESR type slag without deoxidizer addition [J]. Metallurgical and Materials Transactions B, 2020, 51(2): 353-364

[14] ParkS, ParkJ H. Effect of physicochemical properties of slag and flux on the removal rate of oxide inclusion from molten steel [J]. Metallurgical and Materials Transactions B, 2016, 47B(12): 3225-3230

[15] ChangZ, ShiX F, CongJ Q. Study on mechanism of oxygen increase and countermeasure to control oxygen content during electroslag remelting process [J]. Ironmaking & Steelmaking, 2014, 41(3): 182-186

[16] DuanS-c, ShiX, MaoM-t, YangW-s, HanS-w, GuoH-j, GuoJ. Investigation of the oxidation behaviour of Ti and Al in Inconel 718 superalloy during electroslag remelting [J]. Scientific Reports, 2018, 8(1): 1-13

[17] HuangX-HPrinciples of metallurgy [M], 2011, Beijing, Metallurgical Industry Press(in Chinese)

[18] DuanS-c, GuoX-l, GuoH-j, GuoJ. A manganese distribution prediction model for CaO-SiO₂-FeO-MgO-MnO-Al₂O₃ slags based on IMCT [J]. Ironmaking & Steelmaking, 2017, 44(3): 168-184

[19] LeiJ-l, ZhuH-y, ZhaoD-n, XueZ-L. Generation mechanism of MgO and Al₂O₃ inclusions in 51CrV4 spring steel based on the ion-molecule coexistence theory [J]. Metals, 2019, 9(8): 830-836

[20] CHEN Jing-feng, DU Xiao-jian, CHANG Guo-dong, MA Jun-peng, XING Ji-bing. Erosion mechanism and improvement measures for magnesia-calcium brick lining of AOD furnace [C]// Proceedings of the 9th China Steel Annual Conference. Beijing, 2013: 1–4. (in Chinese)

[21] HouD, WangD-y, QuT-p, TianJ, WangH-H. Kinetic study on alloying element transfer during an electroslag remelting process [J]. Metallurgical and Materials Transactions B, 2019, 50(6): 3088-3102

[22] ParkJ, SridharS, FruehanR J. Kinetics of reduction of SiO₂ in SiO₂-Al₂O₃-CaO slags by Al in Fe-Al(-Si) melts [J]. Metallurgical and Materials Transactions B, 2014, 45B(8): 1380-1388

[23] ShiC-b, ChoJ W, ZhengD-l, LiJ. Fluoride evaporation and crystallization behavior of CaF₂-CaO-Al₂O₃-(TiO₂) slag for electroslag remelting of Ti-containing steels [J]. International Journal of Minerals, Metallurgy and Materials, 2016, 23(6): 627-636

[24] ChenJ-XHandbook of common data sheets for steelmaking [M], 20102nd eds.Beijing, Metallurgical Industry Press(in Chinese)

[25] LiS-j, ChengG-g, MiaoZ-q, ChenL, LiC-w, JiangX-Y. Kinetic analysis of aluminum and oxygen variation of G20CrNi2Mo bearing steel during industrial electroslag remelting process [J]. ISIJ International, 2017, 57(12): 2148-2156

[26] NiP-y, TanakaT, SuzukiM, NakamotoM. A kinetic model of mass transfer and chemical reactions at a steel/slag interface under effect of interfacial tensions [J]. ISIJ International, 2019, 59(5): 737-748

[27] ValdezM, ShannonG, SridharS. The ability of slags to absorb solid oxide inclusions [J]. ISIJ International, 2006, 46(3): 450-457