Desulfurization and deoxygenation process for smelting precise or special alloys by using medium-frequency induction furnace multi-slag method

Abstract

The invention discloses a desulfurization and deoxygenation process for smelting precise or special alloys by using a medium-frequency induction furnace multi-slag method. The process is characterizedin that the capacity of a medium-frequency induction furnace is less than or equal to 6 tons, metal raw materials loaded into the furnace must be clean and rust-free, and pure iron is inserted into the furnace in the form of a cast rod. During smelting of one heat steel, the total number of times of repeated new slag making reaches two or more, crusting slag and flowing slag on the surface of a molten pool need to be removed clearly every time slag making is conducted, and a thin slag layer capable of covering the molten steel surface is reserved, and then new slag is made in time. The alkalinity of the slag is 3-3.6, and precipitation and diffusion deoxidation are preformed according to requirements. In the refining period, the temperature of molten steel is controlled to be 1590-1610 DEG C, and the tapping temperature is controlled to be 1610-1630 DEG C. After the molten steel is poured into a steel containing barrel, Ar is blown and stirred, and then the molten steel is cast into asteel ingot under an Ar gas protection device. According to the process, the contents of sulfur and oxygen in the steel can be remarkably reduced, and high-end metal products such as precision or special alloys for cold or hot working can be successfully smelted.

Description

【Technical field】 [0001] The present invention relates to an intermediate frequency induction furnace multi-slag method for smelting precision or special alloy desulfurization and oxygen technology, in particular to an intermediate frequency induction furnace in the smelting process of a furnace of steel, the total number of repeated new slag is up to two or two times The above multi-slag method for smelting precision or special alloy desulfurization and oxygen technology belongs to the field of metallurgy. 【Background technique】 [0002] The Chinese patent with the publication number CN101906504A discloses a smelting process for ultra-low phosphorus steel produced by a converter. The process is characterized in that the molten iron after one desulfurization is produced by the smelting process of multiple times of slagging in the converter. The specific steps are as follows: : Dephosphorize the molten iron after one desulfurization by using the slag blowing method in the ear...

AI Technical Summary

Problems solved by technology

[0006] 1. In the slag of the induction furnace, no induction current can be generated, and its melting and heating completely depend on the heat transfer of the metal to it, which makes the temperature of the slag lower. From a thermodynamic point of view, it is not conducive to the reaction of desulfurization and deoxidation.

[0007] 2. Although the induction furnace will generate a certain stirring force under the action of electromagnetic induction, it is much smaller than other smelting equipment, such as electric arc furnace, AOD furnace, VOD furnace, especially in AOD, in different smelting Selectively blowing Ar, N2, O2 and their mixed gases during the period, and the stirring force generated can make the steel slag in the furnace mix and stir, so as to fully carry out the steel slag reaction; in the medium frequency induction furnace, desulfurization and diffusion deoxidation can only be achieved through diffusion It is carried out on the steel slag interface, and the deoxidized product of precipitation deoxidation floats up from the molten steel into the slag through the weak electromagnetic stirring force. These conditions are also unfavorable for the reaction of desulfurization and deoxidation from a kinetic point of view; in general, The above-mentioned shortcomings are unfavorable factors for the completion of the smelting tasks of high-end metal materials such as precision alloys and special alloys

[0009] (1) The smelting process of the intermediate frequency induction furnace in the prior art is a single slag method. Even if the slag is replaced after the furnace material is melted, it is not thorough. slag, instead of like the multi-slag smelting process of the present invention: remove crusted slag and slag flow on the surface of the molten pool, and leave a layer of thin slag layer that can cover the liquid steel surface, and then add the specified slagging in time lime and fluorspar used

[0011] ⑶ The technology of blowing Ar in the steel ladle can speed up the floating of inclusions in the molten steel, and can escape the gas in the molten steel to a certain extent, and make the composition of the molten steel uniform. The current medium frequency induction furnace smelting generally fails to apply the Ar blowing technology of the ladle , or fail to make strict regulations on the blowing time of Ar, the intensity of blowing Ar and the standing time

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