Desulfurization and deoxidation process for smelting stainless steel in small-capacity AOD (Argon Oxygen Decarburization) furnace by double-slag process

Abstract

The invention relates to a desulfurization and deoxidation process for smelting stainless steel in a small-capacity AOD (Argon Oxygen Decarburization) furnace by a double-slag process, which is characterized in that the capacity of the AOD furnace is smaller than or equal to 10 tons; and the desulfurization and deoxidation process comprises the following steps of: after initial molten steel is added into the AOD furnace, entering the oxygen blowing and decarburization period, adding slag for primary slag-making and carrying out oxygen blowing and decarburization; after the end of the oxygen blowing and the decarburization, entering the rich chromium residue prereduction period, adding a deoxidizing agent to reduce chromium oxide generated in the oxygen blowing and the decarburization, controlling the temperature of the molten liquid within 1700-1820 DEG C after the end of rich chromium residue prereduction; entering the secondary slag-making period, partially slagging off, controllingthe basicity of slag subjected to secondary slag-making within 1.8-3.8 and controlling the time of argon or nitrogen blowing during the secondary slag-making period to be more than or equal to 2 minutes; then entering the molten steel component adjusting period and adjusting molten steel components; and steel-tapping, controlling the steel-tapping temperature within 1570-1670 DEG C, adding moltensteel into a molten steel holding barrel and pouring the molten steel into an steel ingot. By utilizing the process, the contents of sulphur and oxygen can be remarkably reduced, so that high-alloy super austenitic stainless steel, ultra-low carbon double-phase stainless steel and other high-end stainless steel for cold or hot processing can be successfully smelted.

Description

technical field [0001] The invention relates to a smelting process of a small-capacity AOD furnace, in particular to a desulfurization and oxygen process for smelting stainless steel by a double-slag method in the small-capacity AOD furnace, and belongs to the field of metallurgy. Background technique [0002] Publication number is that the Chinese patent of CN1995403A discloses a kind of double slag method to produce the converter process of high-carbon low-phosphorus molten steel, this process sends high-silicon and high-phosphorus molten iron into the converter, and carries out the following steps: Phosphorus slag pouring: add 50%-60% of the total amount of slag-forming materials into the converter, use low-high grab position and high-low oxygen supply flow for blowing operation, and pour out 70%-80% after the early stage of blowing Phosphorus-rich slag, the molten pool temperature at the end of the early stage is controlled to be 1350-1450°C, the basicity of the slag is ...

AI Technical Summary

Problems solved by technology

However, the secondary slagging process consumes a lot of heat. For a large-capacity AOD furnace, due to the large amount of molten steel charged and sufficient heat, it can fully provide the heat required for slagging without affecting the final tapping and pouring. However, for small-capacity AOD furnaces less than or equal to 10 tons, due to the small amount of molten steel charged, a large amount of heat consumed in the secondary slagging process will greatly affect the final molten steel temperature during tapping and pouring

Therefore, usually small-capacity AOD furnaces are only suitable for single-slag method to smelt stainless steel for casting, but not suitable for secondary slag-forming double-slag method to smelt stainless steel products for cold processing or hot processing that have high requirements for desulfurization and oxygen.

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