| Currently, there are many ways for refining in the world. But most of them needcomplex equipment, investment and long construction period. In addition, some smallersteel companies which do not have the processes of hot metal pretreatment and secondaryrefining can not produce qualified steel. Because the process of “BOFâ†'slag washing+argon blowingâ†'CC” has many advantages, such as simple equipment, short process,low-cost, high rates of desulphuration and so on, many manufacturers start to payattention to this process.For low-cost and high-quality steel, Handan Iron and Steel Making Companyanalyses systematically the desulfurization rate of liquid steel, content of oxygen andnitrogen, the composition, type, and distribution law of micro-inclusions and largeinclusion about SS400steel. Through such a study, it can provide theoretical guidance forproducing higher quality steel.The results shows that, after the process of slag washing, the desulfurization rate ofmolten steel can reach33.4%and the content of T[O],[N] in the slab are21.75Ă—10-6,24.9Ă—10-6, which are84.9%,76.1%of the LF process. The content of micro-inclusions inthe slab is5.583/mm2, which is79.2%of the LF process. The content of large inclusionis22.48mg/10kg, which is88.7%of the LF process. In addition, the main compositionsof the micro-inclusions in slab and tundish are calcium-aluminates. There is none Al2O3inclusion in tundish after the process of slag washing, but the content of Al2O3inclusionin tundish and slab is13%and8.6%after LF process. It suggests that the process of slagwashing has a better result to remove the Al2O3inclusion and has a better modificationeffect to Al2O3inclusion.Through the analysis metioned above, the two kinds of processes have the samedesulfurization requirements, but the former has a better cleanliness and lower costing.Comprehensive consideration, it is feasible to use “BOFâ†'slag washing+argonblowingâ†'CC” process to produce low-cost, high quality SS400steel. |
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