Converter smelting process using dephosphorization agent

Abstract

The invention pertaining to the field of convertor steelmaking technology provides a technique of converter smelting by using a dephosphorization agent. In a same convertor, dephosphorization is performed by using a CaO-base ephosphorization agent containing a few CaCl2 under favorable thermodynamics and combined-blowing dynamics conditions such as low temperature at the prior period, high content of iron oxide and the like, the prior period, desilication and dephosphorization slags of 50-70% are poured away in the molten iron preprocessing process, in the later period, decarburization process is performed and decarburization slag is formed and is then utilized as dephosphorization slag of the lower converter. According to the smelting technology, CaCl2 is added to the CaO-base ephosphorization agent to accelerate the burn-off rate of CaO by using the eutectic point character of CaCl2 and CaO binary system, the utilization ratio of lime is also improved, the utilizing of decarburization slag not only fully utilizes the physics heat brought by the decarburization slag, but also provides high content iron oxide for the dephosphorization of the prior period and accelerates the dephosphorization reaction.The invention has advantages of low cost of investment, shortened smelting period, carbon content of 0.4% at the end point of smelting, phosphorus content capable of being reduced to 0.006% and dephosphorization ratio up to 95.5%.

Description

technical field

[0001] The invention belongs to the technical field of converter steelmaking, and in particular provides a converter smelting process using a dephosphorizing agent. Suitable for converter smelting medium and high carbon steel. Background technique

[0002] Phosphorus is a harmful element for most steel grades. Because phosphorus in steel can significantly reduce the toughness of steel, especially temper toughness and impact toughness. Under low temperature conditions, the deterioration of toughness is particularly significant, resulting in the "cold brittleness" of steel, and with the increase of carbon, nitrogen, and oxygen content in steel, this harmful effect of phosphorus is enhanced. The segregation of phosphorus in the solidification process of molten steel is relatively serious, and it is easy to make the local structure of the steel abnormal, resulting in uneven mechanical properties, and also has an adverse effect on welding performance. Therefore...

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