(1. Research Institute of Technology, Shougang Group Co., Ltd., Beijing 100043, China 2. Shougang Jingtang United Iron and Steel Co., Ltd., Tangshan 063200, Hebei, China)
Abstract:Calcium treatment to the cleanliness of wheel steel was studied, Wheel steel produced through the process of BOF, LF refining treatment, RH refining treatment, calcium treatment and continuous casting was sampled systematically. The morphology, size and composition of inclusions were analyzed by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS). The results show that the composition of inclusions are Al2O3-CaO with a small amount of MgO and SiO2 before calcium treatment. The size of these inclusions is within 5 μm. After calcium treatment, the inclusions are mainly Al2O3-CaO-CaS, with the morphology of discontinuous clusters in the coil. Some of these inclusions are larger than 10 μm. The number density of inclusions with the size of 1 to 5 μm deceases from 10 to 3.1 /mm2 from RH, tundish to hot rolling. The number density of inclusions ranging from 5 to 10 μm in size is less than 1 /mm2. The number density of inclusions larger than 10 μm is less than 0.2 /mm2. The[w(T[O])]of slab is less than 0.001 0%. The element mapping analysis of inclusions shows that the inclusions in coil are mainly CaS-CaO-Al2O3 and CaO- Al2O3-MgO. The change in the morphology of inclusions in the rolling process is analyzed. The deformed inclusions after the rolling are CaO-Al2O3, while The non-deformable inclusions are CaO-Al2O3 wrapped with CaS.
Keskinkilic E. Sulfide-type inclusion morphologies of a Ca-treat-ed hot-rolled wheel steel[J]. The Journal of the Southern African Institute of Mining and Metallurgy,2011,111:417.
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Keskinkilic E. Sulfide-type inclusion morphologies of a Ca-treat-ed hot-rolled wheel steel[J]. The Journal of the Southern African Institute of Mining and Metallurgy,2011,111:417.