2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 6: Yagi Intl. Symp. / Metals & Alloys Processing
| Editors: | Kongoli F, Akiyama T, Nogami H, Saito K, Fujibayashi A |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 480 pages |
| ISBN: | 978-1-987820-46-1 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Influence of Deoxidation and VOD Slag on the Inclusions' Behavior of Ti-Nb Stabilized Fe-21Cr Ferrite stainless steel
Guangqiang Li1; Su Lijuan2; Chengyi Zhu3; Junying Zhang4; Xiaoyu Liang3;1WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Wuhan, China; 2SOOCHOW UNIVERSITY, Suzhou, China; 3KEY LABORATORY FOR FERROUS METALLURGY AND RESOURCES UTILIZATION OF MINISTRY OF EDUCATION, WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Wuhan, China; 4SCHOOL OF INFORMATION SCIENCE AND ENGINEERING, WUHAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, Wuhan, China;
Type of Paper: Regular
Id Paper: 3
Topic: 3
Abstract:
Ultra pure ferritic stainless steels are Fe-Cr or Fe-Cr-Mo alloys bearing 11%~30% Cr and total C and N contents are limited to less than 0.015%. Ultra pure ferritic stainless steels are appreciated for their excellent uniform and localized corrosion resistance. Unfortunately, large inclusions such as Al2O3, TiOx, TiN, MgO and their complex in the steel are harmful to the surface quality, corrosion resistance and mechanical performance of the products. It is necessary to optimize the composition of VOD refining slag to absorb the inclusions in the practical production process. The influence of deoxidation process and VOD slag compositions on the behavior of inclusions during refining of Ti-Nb stabilized Fe-21%Cr ferrite stainless steels were studied in this work. The results indicated that the main inclusions in the Al-Si deoxidized samples were MgO¡€Al2O3. And the main inclusions after Ti addition were MgO¡€Al2O3-TiOx and Al2O3-TiN. After calcium treatment, the main inclusions became spherical MgO¡€Al2O3-CaO and Al2O3-SiO2-CaO combined with TiOx and TiN. As the basicity of refining slag was increased from 2.5 to 4, the number density of inclusions in the sample reduced, while the average particle size of inclusions increased. When the basicity of refining slag was 3.5, reducing Al2O3 content in the refining slag was conducive to decrease the number of larger inclusions. There were fewer inclusions and the size of most inclusions was distributed within 1 to 2ŠIm when the Ti-Nb stabilized Fe-21%Cr ferrite stainless steel was refined with the optimized refining slag with the composition of CaO-SiO2-20%Al2O3-10%MgO-5%CaF2 and the basicity of 3.5. The experiment about the influence of refining slag on the inclusions in Nb stabilized Fe-18Cr ferrite stainless steel without titanium was carried out, too. The refining slag which the composition of CaO-SiO2-10%Al2O3-10%MgO-5%CaF2 and R=3.5 had a good refining effect for Nb stabilized Fe-18Cr ferrite stainless steel.
Keywords:
Metallurgy; Slag; Steel;References:
[1] S. Lu, Y. Zhang, C. Yang, Stainless Steel, 1995, Atomic Energy Press, 24-26 (in Chinese).[2] Q. Lin, J. Zhang, New Development of Productive Technology of Stainless Steel, Special Steel, 20(1999), 7-14 (in Chinese)
[3] Y. Cen, G. Zhang, The Development of Stainless Steelmaking Techniques, Shanghai Metals, 21(1999), 11-16 (in Chinese)
[4] C. Zhang, Z. Liu, H. Zheng, Effects of Addition of Nb and Ti on Solidification Structure and Surface Ridging of An Ultra Purified Ferritic Stainless Steel, Transactions of Materials and Heat Treatment, 32(2011), 23-28 (in Chinese)
[5] Z. Chen, Y. Xu, L. Gu, Progress of Study on Inclusion Control of Ultra Clean Ferritic Stainless Steel, World Iron & Steel, 10(2010), 1-11 (in Chinese)
[6] Y. Xu, Z. Chen, L. Gu, Proceedings of the 14th National Steel Quality and Non-metallic Inclusion Control Seminars, Guilin China, 2010, 221-227 (in Chinese)
[7] A. Ito, H. Suito, R. Inoue, Size Distribution of multi-phase deoxidation particles for heterogeneous crystallization of TiN and solidification structure in Ti-added ferritic Stainless Steel, ISIJ International, 52(2012), 1196-1205
[8] H. Yang, L. Su, G. Li, Influence of Refining Slag on the Inclusions in SUS444 Ferrite Stainless Steel, Steelmaking, 30(2014), 42-46 (in Chinese)
[9] G. Yuan, G. Li, Y. Li, An Experiment Study on Silicon-aluminum Complex Deoxidation of Titanium Bearing Ultra-pure Ferritic Stainless Steel, Journal of iron and steel research, 25(2013), 33-38 (in Chinese)
[10] J. H. Park, H. Todoroki, Control of MgO·Al2O3 Spinel Inclusions in Stainless Steels, ISIJ International, 50 (2010), 1333-1346