| This paper, on the basis of referencing a large number of available documents, as well as analyzing and summarizing researches on the non-metallic inclusions at home and abroad, through using the ways of sampling in production site for metallographic analysis, scanning electron microscopy analysis, studied the changes of the number and size of non-metallic inclusions of SPHE and the evolution of non-metallic inclusions species at all stages of LD-BAr-RH-CC process, and also analyzed the source of non-metallic inclusions in the process.The results showed that: in the LD-BAr-RH-CC refining operation process,the number of unit area and area percentage of non-metallic inclusions in molten steel on the process were with the whole way downward, this show that refining of BAr, RH, and the tundish process are significant for purifying molten steel and reducing non-metallic inclusions in it. Throughout the process, the small particles mixed with constant collision, grew up, resulting in 0 5μm, and a mixture of 5 10μm in general all the way downward while the number of larger particles reduced relative non-obviously, Because the whole process, there were the larger particles of inclusions floating, but also in motion, small particles mixed with constant collisions come into larger particles. in the LD-BAr-RH-CC process,Al2O3 become main inclusions before liquid steel arriving Argon station;after blowing Argon,Al2O3 + MnO become main inclusions; After RH treatment, Al2O3 inclusions increased; in the tundish, composite inclusions become main inclusions in molten steel.According to the researches, in order to enhance quality of SPHE steel, to reduce and improve non-metallic in steel inclusions under current conditions, the followings are some measure and suggestions: optimizing the operation of Ar blowing to help the floating of the inclusions; strengthening the protective casting to avoid the second oxidization; Non-metallic inclusions in molten steel for degeneration treatment. |
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