Comprehensive deoxidizing and desulfurizing process for smelting stainless steel by using small-capacity AOD (Argon Oxygen Decarburization) furnace

Abstract

The invention discloses a comprehensive deoxidizing and desulfurizing process for smelting stainless steel by using a small-capacity AOD (Argon Oxygen Decarburization) furnace. The comprehensive deoxidizing and desulfurizing process is characterized in that the furnace capacity of the AOD furnace is less than or equal to 10 tons, and primary molten steel added into the AOD furnace meets the specified requirements. After the oxygen-blowing decarburization period ends, a chromium-rich slag pre-reduction period begins, Ar(N2) is blown for more than or equal to 6 minutes, and the temperature of the molten steel is controlled to be 1770-1820 DEG C. In the secondary slagging period, after 80 to 90 percent of slag in the furnace is removed, lime and fluorite meeting the specified requirements are added; and after secondary new slag is formed, a comprehensive deoxidizing and desulfurizing agent which is composed of a deoxidizing agent metal Al block, a composite deoxidizing and desulfurizing agent Si-Ca block and a composite deoxidizing and desulfurizing agent Si-Ca-Ba-Al block and meets the specified requirements is added, and Ar(N2) is blown for more than or equal to 6 minutes. The tapping temperature is 1600-1640 DEG C. According to the process, on the basis of the prior art, the oxygen content of steel is remarkably reduced, and the quality of high-end stainless steel for cold (hot) machining deformation is improved.

Description

【Technical field】 [0001] The invention relates to a smelting process of a small-capacity AOD furnace, in particular to a comprehensive deoxidation and desulfurization process for smelting stainless steel in a small-capacity AOD furnace, belonging to the field of metallurgy. 【Background technique】 [0002] In stainless steel, the requirements for oxygen and sulfur content are lower, especially for high-end metal materials such as ultra-low carbon austenitic stainless steel, super austenitic stainless steel, and super duplex stainless steel with high alloy content. In order to reduce the oxygen and sulfur content in the steel, the requirements for the process are: on the one hand, the secondary reduction slag in the double slag method must be produced; on the other hand, it is required to add deoxidation and sulfur agents to the steel, and the Deoxidation and sulfur agents have greater affinity with oxygen and sulfur in steel, and can play a greater role in deoxidation, and th...

AI Technical Summary

Problems solved by technology

The process of the present invention is: in the secondary slagging period, a comprehensive deoxidation and sulfur agent composed of deoxidizer Al block, composite deoxidizer, sulfur agent Si-Ca and Si-Ca-Ba-Al is used, wherein Si-Ca-Ba- Al has a unique effect that Al blocks and Si-Ca blocks do not have (see the explanation of the technical features involved in the present invention described later), and the addition amount and proportion of each deoxidation and sulfur agent meet certain requirements, and has the depth of molten steel The advantages of deoxidation and sulfur, and after deoxidation and sulfur are completed, the Al content in the finished steel must be controlled to be ≤0.017%, and the Si content in the finished steel should be ≤70% of the standard upper limit to reduce the B-type brittle inclusion Al in the steel 2 o 3 and silicate inclusion content, such a comprehensive deoxidation and sulfur process has not been reported so far

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