Mechanical Characteristics of Structural Thick Plates Depending on Vacuum Time of RH Process

Abstract:

The structural thick plates were manufactured by varying the vacuum time at a constant argon gas flow rate and degree of vacuum during the Ruhrstahl Heraeus (RH) refining process. The inclusion and mechanical properties of the structural thick-plate specimens were evaluated according to vacuum time. The nitrogen in the converter had an effect after the RH process, and as the vacuum time of the RH process increased, the nitrogen content also increased. The nitrogen in the continuous casting (CC) decreased more than that in the converter, and as the vacuum time increased, the hydrogen decreased. Al₂O₃·CaO, MnS and Al₂O₃·MgO inclusions were observed in the structural thick plate. The average size of the oxides was (6.1 to 33.46) μm, while the average size of the Al-O-based inclusions was (4.26 - 6.3) μm. The mechanical properties, such as tensile strength, yield strength, and elongation, were affected by the vacuum time of the RH process with 10 min being the best. The micro-Vickers hardness showed dispersion regardless of the vacuum time of the RH process, which can be explained by the Weibull probability distribution. From the shape and scale parameters, although the specimen with the vacuum time of the RH process of 10 min showed a large dispersion in the micro-Vickers hardness, the characteristic value of 63.2 % was the best.

• Periodical: Advanced Materials Research (Volume 1178)
• Pages: 45-55
• DOI: https://doi.org/10.4028/p-s6gL9t
• Online since: July 2023
• Authors: Ki Hang Shin, Byoung Chul Choi, Ki Woo Nam*
• Keywords: Argon Gas Flow, Continuous Casting (CC), Mechanical Properties, Ruhrstahl Heraeus (RH), Structural Steel Plate, Vacuum Time, Weibull Characteristics

References

[1] J. Toribio, F.J. Ayaso, B. Gonzalez, Role of non-metallic inclusions in the fracture behavior of cold drawn pearlitic steel, metal, 11 (2021) 962

DOI: 10.3390/met11060962

[2] A. Costa e Silva, The effects of non-metallic inclusions on properties relevant to the performance of steel in structural and mechanical applications, Journal of Materials Research and Technology, 8 (2019) 2408-2422

DOI: 10.1016/j.jmrt.2019.01.009

[3] J.H. Park, I.H. Jung, H.G. Lee, Dissolution behavior of Al2O3 and MgO inclusions in the CaO– Al2O3–SiO2 slags: formation of ring-like structure of Mg Al2O3 and Ca2SiO4 around MgO inclusions, ISIJ International, 46 (2006) 1626-1634

DOI: 10.2355/isijinternational.46.1626

[4] P.R. Scheller, Q. Shu, Inclusion Development in Steel During Ladle Metallurgical Treatment - A Process Simulation Model – Part: Industrial Validation, Steel Research International, 85 (2014) 1310-1316. http://doi.prg/

DOI: 10.1002/srin.201300375

[5] Y. Ren, L. Zhang, W. Fang, Effect of addition of Al-based slag deoxidizer on MgO.Al2O3 inclusions in 3Si-Fe steels, Metallurgical Research & Technology, 114 (2017) Article No. 108

DOI: 10.1051/metal/2016043

[6] K Steneholm, M Andersson, A Tilliander, P.G. Jönsson, Removal of hydrogen, nitrogen and sulphur from tool steel during vacuum degassing, Ironmaking & Steelmaking, 40 (2013) 199-205

DOI: 10.1179/1743281212Y.0000000029

[7] P. Singha, S. Yadav, A.K. Shukla, Ladle Steelmaking Processes Using FactSage and Its Macro Facility, Proceedings of the Iron & Steel Technology Conference, 16–18 May 2022, Pittsburgh, Pa., USA, 2022, 1723-1728

DOI: 10.33313/386/203

[8] L. Wang, S. Yang, J. Li, T. Wu, W. Liu, J. Xiong, Improving Cleanliness of 95CrMo Drill Rod Steel by Slag Refining, Metallurgical and Materials Transactions B, 47 (2016) 99-107

DOI: 10.1007/s11663-015-0481-0

[9] J. Strandh, K. Nakajima, R. Eriksson, P. Jonsson, Solid Inclusion Transfer at a Steel-Slag Interface with Focus on Tundish Conditions, ISIJ International, 45 (2005) 1597-1606

DOI: 10.2355/isijinternational.45.1597

[10] X.F. Zhang, W.J. Lu and R.S. Qin, Removal of MnS inclusions in molten steel using electropulsing, Scripta Materialia, 69 (2013) 453-456

DOI: 10.1016/j.scriptamat.2013.05.033

[11] L.O. Uhrus, Through Hardening Steels for Ball Bearings- Effect of Inclusions on Endurance, Iron Steel Inst. Spec. Rep. 77 (1963) 104-109.

[12] Y. Murakami, Effects of Small Defects and Nonmetallic Inclusions on the Fatigue Strength of Metals, JSME International Journal, 32 (1989) 167-180

DOI: 10.1299/jsmea1988.32.2_167

[13] J.C. Pang, S.X. Li, Z.G. Wang, Z.F. Zhang, General relation between tensile strength and fatigue strength of metallic materials, Materials Science & Engineering A, 564 (2013) 331-341

DOI: 10.1016/j.msea.2012.11.103

[14] A. Patra, Oxide Dispersion Strengthened Refractory Alloys - 1st Edition, CRC Press. (2022)

[15] G. Wang, L. Huang, X. Zhan, L. Tan, Z. Qin, W. He, F. Liu, Strength-hardness correlations of thermal-exposed oxide dispersion strengthened nickel-based superalloy with different grain size distributions, Materials Characterization, 178 (2021) Article No. 111178

DOI: 10.1016/j.matchar.2021.111178

[16] L. Raman, K. Gothandapani, B.S. Murty, Austenitic Oxide Dispersion Strengthened Steels: A Review, Defence Science Journal, 66 (2016) 316-322

DOI: 10.14429/dsj.66.10205

[17] W. Weibull, A Statistical Distribution Function of Wide Applicability, ASME Journal of Applied Mechanics, 18 (1951) 293-297

DOI: 10.1115/1.4010337