1 School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China 2 Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
Cite this article:
Wen YANG,Lifeng ZHANG,Ying REN,Haojian DUAN,Ying ZHANG,Xianghui XIAO. QUANTITATIVE 3D CHARACTERIZATION ON OXIDE INCLUSIONS IN SLAB OF Ti BEARING FERRITIC STAINLESS STEEL USING HIGH RESOLUTION SYNCHROTRON MICRO-CT. Acta Metall Sin, 2016, 52(2): 217-223.
Non-metallic inclusions especially oxides are detrimental to the quality of ferritic stainless steel products. Accurate characterization on inclusions is conducive to further research on the inclusion control. There are some disadvantages in traditional 2D or 3D inclusion detection methods, tomography is thus employed to characterize inclusions in steel in the current work. Oxide inclusions in the slab of Ti bearing ferritic stainless steel were characterized 3 dimensionally using high resolution synchrotron micro computed tomography (Micro-CT), and the variations of quantity, volume and size of oxide inclusions along the thickness of continuous casting slab were analyzed quantitatively and compared with the 2D results detected by ASPEX, an automated scanning SEM. It was found that non-destructive detection could be well done by Micro-CT more accurately. The detected oxides by Micro-CT were mainly global, and the number of inclusions decreased with increasing size. In general, the number density and volume fraction of oxides were largest in the center of slab thickness, and decreased with the distance from center, reached the smallest value near the surface of slab. Contrarily, the average of equivalent diameter of oxide inclusions was largest near slab surface, and was smallest near quarter of thickness on the loose side.
Fig.1 Schematic of apparatus and mechanism of Micro-CT
Fig.2 Schematics of sampling locations in slab
Fig.3 Morphologies and compositions of typical oxide inclusions in the slab of Ti bearing stainless steel
Fig.4 Morphology of inclusions extracted by electrolytic extraction using non-aqueous electrolyte
Fig.5 Morphologies and distributions of oxides in different thickness of slab detected by Micro-CT
Fig.6 Distributions of equivalent diameters (DE) of oxides in different locations of slab
Fig.7 Variation of number density in volume of oxides along thickness of slab (DE≥5 μm)
Fig.8 Variation of volume fraction of oxides along thickness of slab (DE≥5 μm)
Fig.9 Variation of average of equivalent diameter of oxides along thickness of slab (DE≥5 μm)
Fig.10 Variation of number density in area (a) and area fraction (b) of oxides along thickness of slab detected by ASPEX (≥5 μm)
Fig.11 Variation of average diameter of oxides along thickness of slab detected by ASPEX (≥5 μm)
[1]
Zhang L F, Li Y L, Ren Y.Iron Steel, 2013; 48(11): 1
[1]
(张立峰, 李燕龙, 任英. 钢铁, 2013; 48(11): 1)
[2]
Zhang L F, Li Y L, Ren Y.Iron Steel, 2013; 48(12): 1
[2]
(张立峰, 李燕龙, 任英. 钢铁, 2013; 48(12): 1)
[3]
Ren Y, Zhang L F, Yang W.Steelmaking, 2014; 30(1): 71
[3]
(任英, 张立峰, 杨文. 炼钢, 2014; 30(1): 71)
[4]
Ha H Y, Park C J, Kwon H S.Corros Sci, 2007; 49: 1266
[5]
Chang E, Zheng H G, Zhang L, Yang J.Shanghai Met, 2008; 30(6): 18
[5]
(常锷, 郑宏光, 张丽, 杨军. 上海金属, 2008; 30(6): 18)
[6]
Zhang L F, Yang W, Zhang X W, Luo Y, Liu Y.Iron Steel, 2014; 49(2): 1
[6]
(张立峰, 杨文, 张学伟, 罗艳, 刘洋. 钢铁, 2014; 49(2): 1)
[7]
Zhang L F, Zhang X W, Luo Y, Liu Y, Zhang Y, Yang W.In: The Chinese Society for Metals ed., Proc 9th CSM Steel Congress, Beijing: Metallurgical Industry Press, 2013: 1
