Influence of power frequency on cleanliness of electroslag ingot during electroslag remelting process
CHANG Li-zhong1, SU Yun-long1, ZHANG Long-fei1, ZHU Chun-li1, XU Tao2, SHI Xiao-fang1
1. School of Metallurgy Engineering, Anhui University of Technology, Ma'anshan 243002, Anhui, China; 2. Special Metallurgy Division, Anhui Fukai Special Material Co., Ltd., Jixi 245300, Anhui, China
Abstract:In the process of electroslag remelting, low-frequency power supply can improve power factor, reduce power consumption and realize three-phase balance of power system. However, the influence of power frequency on the metallurgical quality of electroslag ingot, especially the cleanliness, is still lack of sufficient data support. Based on the small-scale low-frequency electroslag remelting experiments in the laboratory, the effects of different power supply frequencies, especially low supply frequencies on the cleanliness of ingot were studied and the effect lows of power frequencies on chemical composition, oxygen and nitrogen content, inclusion distribution in the 304 austenitic stainless steel and GCr15 bearing steel electroslag ingots were analyzed in detail. The results show that compared with power frequency electroslag remelting, when low frequency (2, 1, 0.4, 0.1 Hz) electroslag remelting is adopted for both stainless steel and bearing steel (other experimental parameters such as the composition and weight of slag, smelting current and voltage, remelting atmosphere etc, are exactly the same), the oxygen content in electroslag ingots increases greatly, both between 0.010% and 0.013%. But the frequency variation has little effect on nitrogen content. The content of aluminum in electroslag ingot also increases significantly, while other chemical compositions change little. Correspondingly, the number of inclusions in low frequency electroslag ingot also increases significantly, and the increased inclusions are mainly alumina. However, the inclusions are mainly small inclusions less than 10 μm, the large inclusions increase slightly, but the number is very small. The main reason for increase of oxygen content is that the DC effect of low-frequency power supply causes the electrolysis of alumina in the remelting slag pool (30% Al2O3+70% CaF2 slag system) which leads to the increase of aluminum and oxygen content. The total oxygen content of ESR ingot increases when the aluminum and oxygen formed by alumina electrolysis enter the molten metal pool. With the cooling and solidification of metal pool, oxygen and aluminum form alumina inclusions, which remain in the electroslag ingot. The DC electrolysis effect of low-frequency power supply in industrial production needs to be further analyzed.
常立忠, 苏云龙, 张龙飞, 朱春丽, 徐涛, 施晓芳. 电渣重熔过程电源频率对电渣锭洁净度的影响[J]. 钢铁, 2022, 57(7): 43-53.
CHANG Li-zhong, SU Yun-long, ZHANG Long-fei, ZHU Chun-li, XU Tao, SHI Xiao-fang. Influence of power frequency on cleanliness of electroslag ingot during electroslag remelting process[J]. Iron and Steel, 2022, 57(7): 43-53.
[1] 李正邦. 电渣冶金的理论与实践[M]. 北京: 冶金工业出版社, 2010.(LI Zheng-bang. Electroslag Metallurgy Theory and Practice[M]. Beijing: Metallurgical Industry Press,2010.) [2] 王迪,杨树峰,曲敬龙,等. GH4169电渣重熔铸锭表层夹杂物分布规律[J]. 钢铁, 2021,56(2):155.(WANG Di, YANG Shu-feng, QU Jing-long, et al. Distribution of inclusions on surface of GH4169 ESR ingot[J]. Iron and Steel, 2021,56(2):155.) [3] 宋惠东, 李晶, 史成斌, 等. 8Cr13MoV钢电渣重熔过程中夹杂物行为[J]. 钢铁, 2016,51(8):41.(SONG Hui-dong, LI Jing, SHI Cheng-bin, et al. Evolution of inclusions in 8Cr13MoV steel during ESR process[J]. Iron and Steel, 2016,51(8):41.) [4] 李正邦. 电渣冶金设备及技术[M]. 北京: 冶金工业出版社, 2012.(LI Zheng-bang. Electroslag Metallurgy Equipment and Technology[M]. Beijing: Metallurgical Industry Press,2012.) [5] ZANG Xi-min, JIANG Zhou-hua, PAN Tie-yi. Development and investigation of electroslag continuous casting[J]. Journal of University of Science and Technology Beijing, 2007, 14(4): 302. [6] Roberts R J. Electroslag remelting (ESR) at consarc[C]// Medovar Memorial Symposium. Ukraine: Paton Electric Welding Institute, 2001:15. [7] 郝学卓, 姚艳平, 刘喜海, 等. 20 t数控型三相保护气氛电渣熔铸炉开发与应用[J]. 中国重型装备, 2017(1): 28.(HAO Xue-zhuo, YAO Yan-ping, LIU Xi-hai, et al. Development and application of 20 tons numerical control electroslag casting furnace with three-phase atmosphere protection[J]. China Heavy Equipment, 2017(1): 28) [8] 吕鹏. 大吨位电渣炉低频供电关键技术研究[D]. 西安: 西安石油大学, 2017.(LÜ Peng. Key Technology of Large-tonnage Electroslag Furnace Low Frequency Power Supply[D]. Xi'an: Xi'an Shiyou University, 2017.) [9] 余坤, 吁安山,杨湘杰. 低频电渣重熔对NO8367奥氏体不锈钢组织性能的影响[J].特种铸造及有色合金,2019,39(2):133. (YU Kun, YU An-shan, YANG Xiang-jie. Effect of low frequency electroslag remelting on microstructure and properties of no8367 austenitic stainless steel[J]. Specail Casting and Nonferrous Alloys, 2019, 39(2):133.) [10] 危亚军, 郭显胜, 黄永钢,等. 80 t低频气保恒熔速电渣炉的技术特点及应用[J]. 中国冶金,2017,27(6):58.(WEI Ya-jun, GUO Xian-sheng, HUANG Yong-gang, et al. Technical feature and application of 80 t ESR furnace with low-frequency, gas protection and constant melting rate[J].China Metallurgy, 2017, 27(6): 58.) [11] Watkins Edward J,Tihansky Eugene L. Production of a 304 stainless steel nuclear reactor forging from a very large electroslag reefing ingot[C]//Steel Forgings. Philadelphia:ASTM, 1986: 439. [12] WANG Huai, ZHONG Yun-bo, LI Qiang, et al. Influences of the transverse static magnetic field on the droplet evolution behaviors during the low frequency electroslag remelting process[J]. ISIJ International, 2019, 57(12):2157. [13] Sibaki E Karimi, Kharicha A, Wu M, et al. A numerical study on the influence of the frequency of the applied AC current on the electroslag remelting process[C]//International Symposium on Liquid Metal Processing and Casting 2013. New Jersey: John Wiley and Sons Inc, 2013: 13. [14] Kharicha A, Wu M, Ludwig A, et al. Influence of the frequency of the applied AC current on the electroslag remelting process[C]//CFD Modeling and Simulation in Materials Processing. New Jersey: John Wiley and Sons Inc, 2012: 139. [15] LIANG Qiang, CHEN Xi-chun, REN Hao, et al. Numerical simulation of electroslag remelting process for producing GH4169 under different current frequency[C]//3rd International Conference on Manufacturing Science and Engineering. Clausthal-Zellerfeld: Trans Tech Publications,2012:482. [16] CHANG Li-zhong, SHI Xiao-fang, YANG hai-sen, et al. Effect of low-frequency ac power supply during electroslag remelting on qualities of alloy steel[J]. Journal of Iron and Steel Research, International, 2009, 16(4):7. [17] 徐涛,马红军,吴振忠,等. G102Cr18Mo不锈轴承钢VIM-VAR冶炼过程夹杂物的演变[J]. 中国冶金, 2021,31(5):39.(XU Tao, MA Hong-jun, WU Zhen-zhong,et al. Evolution of inclusions in G102Cr18Mo stainless bearing steel during VIM-VAR refining process[J].China Metallurgy, 2021,31(5):39.) [18] 常立忠,杨海森,李正邦. 电渣重熔过程中的氧行为研究[J]. 炼钢,2010,26(5):46. (CHANG Li-zhong, YANG Hai-sen,LI Zheng-bang. Study on oxygen behavior during electroslag remelting[J]. Steelmaking, 2010, 26(5):46.) [19] 常凯华, 徐涛,朱春丽,等. 电渣重熔对GCr15轴承钢中氧含量及夹杂物的影响[J]. 钢铁钒钛, 2021,42(4):175. (CHANG Kai-hua, XU Tao, ZHU Chun-li, et al. Effect of ESR on oxygen content and inclusions in GCr15 bearing steel[J]. Iron Steel Vanadium Titanium, 2021, 42(4):175.) [20] 鲁连涛, 李伟, 张继旺, 等. GCr15钢旋转弯曲超长寿命疲劳性能分析[J]. 金属学报, 2009, 45(1): 73.(LU Lian-tao, LI Wei, ZHANG Ji-wang, et al. Analysis of rotary bending gigacycle fatigue properties of bearing steel GCr15[J]. Acta Metallurgica Sinica, 2009, 45(1): 73.) [21] 黄宇,成国光,王启明,等. 大尺寸夹杂物对12MDV6铸件冲击性能的影响[J]. 中国冶金, 2020,30(6):39.(HUANG Yu, CHENG Guo-guang,WANG Qi-ming, et al. Effect of large inclusion on impact toughness of 12MDV6 casting[J].China Metallurgy, 2020,30(6):39.) [22] 张继明, 张建锋, 杨振国, 等. 高强钢中最大夹杂物的尺寸估计与疲劳强度预测[J]. 金属学报, 2004, 40(8): 846.(ZHANG Ji-ming, ZHANG Jian-feng, YANG Zhen-guo, et al. Estimation of maximum inclusion size and fatigue strength in high strength steel[J]. Acta Metallurgica Sinica,2004, 40(8): 846.) [23] 车晓健,杨卯生,唐海燕,等. 高性能GCr15轴承钢中夹杂物控制与疲劳性能[J]. 钢铁, 2018,53(5):76.(CHE Xiao-jian, YANG Mao-sheng, TANG Hai-yan, et al. Inclusion control and fatigue performance in high performance GCr15 bearing steel[J]. Iron and Steel, 2018, 53(5):76.) [24] 赵培林,韩文习,杨志杰,等. 夹杂物对海工用H型钢冲击韧性影响及分析[J]. 中国冶金,2020,30(2):74.(ZHAO Pei-lin,HAN Wen-xi, YANG Zhi-jie,et al.Effect of inclusions on impact toughness of H-shaped steel for marine engineering[J]. China Metallurgy, 2020,30(2):74.) [25] Kawakami M, Takenaka T, Ishikawa M. Electrode reactions in DC electroslag remelting of steel rod[J]. Ironmaking and Steelmaking, 2002, 29(4):287. [26] 姜周华, 董艳伍, 耿鑫, 等. 电渣冶金学[M]. 北京:科学出版社, 2015.(JIANG Zhou-hua, DONG Yan-wu, GENG Xin, et al. Electroslag Metallurgy[M]. Beijing: Science Press, 2015.) [27] Kato M, Hasegawa K, Nomura S, et al. Transfer of oxygen and sulfur during direct-current electroslag remelting[J]. Transactions of the Iron and Steel Institute of Japan, 1983, 23(7):618. [28] CHANG Li-zhong, SHI Xiao-fang, CONG Jun-qiang. Study on mechanism of oxygen increase and countermeasure to control oxygen content during electroslag remelting process[J]. Ironmaking and Steelmaking, 2014, 41(3):182. [29] 蒋汉赢. 冶金电化学[M]. 北京: 冶金工业出版社, 1983.(JIANG Han-ying. Metallurgical Electrochemistry[M]. Beijing: Metallurgical Industry Press, 1983.) [30] 王捷. 电解铝生产工艺与设备[M]. 北京: 冶金工业出版社, 2006.(WANG Jie.Electrolytic Aluminum Production Process and Equipment[M]. Beijing: Metallurgical Industry Press, 2006.)