Molten steel deoxidizing and microalloying method

Abstract

The invention provides a molten steel deoxidizing and microalloying method. The molten steel deoxidizing and microalloying method comprises the following steps of blowing oxygen to the top of a top-bottom combined blowing converter, blowing inert gas to the bottom of the top-bottom combined blowing converter for smelting, or blowing inert gas to the bottom of molten steel in an electric furnace for smelting; after main chemical components are qualified, blowing a deoxidizing agent to the bottom with inert gas as a carrier for refining; and when the oxygen content in the molten steel is less than or equal to 200 ppm, blowing alloyed powder into the molten steel with inert gas as a carrier for microalloying treatment, wherein the blowing amount of the alloyed powder is less than or equal to10 kg / t of the molten steel.According to the molten steel deoxidizing and microalloying method, the inert gas is blown to the bottom, and after the deoxidizing agent is blown into the molten steel todeoxidize the molten steel, the alloyed powder is blown for direct microalloying, so that components of the molten steel can be more uniform; a brand new concept is provided for directly microalloyingmicroalloy elements in the steel material production process; the microalloy elements existing in the form of solid solution can be effectively obtained out of a steel material, and thus, the steel performance is improved.

Description

technical field [0001] The invention relates to the technical field of top-bottom combined blowing converter steelmaking technology, in particular to a method for deoxidation and microalloying of molten steel. Background technique [0002] Micro-alloying elements usually refer to the addition of trace carbonitride-forming elements such as niobium, vanadium, titanium, rare earth elements, and boron elements on the basis of the original main alloying elements, thereby affecting mechanical properties, or affecting corrosion resistance, Heat resistance plays a role; in the modern steel production process, due to the continuous development of low-oxygen, low-sulfur and high-purity smelting technology, it provides the necessary prerequisites for the microalloying of microalloying elements. [0003] As early as the 1940s, Japan, the United States, Germany, etc. successively studied and applied tungsten ore powder instead of tungsten-iron alloy in electric furnaces, open hearth furn...

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Problems solved by technology

[0003] As early as the 1940s, Japan, the United States, Germany, etc. successively studied and applied tungsten ore powder instead of tungsten-iron alloy in electric furnaces, open hearth furnaces and induction furnaces for direct reduction alloying, and the research on direct microalloying kicked off; in the 20th century In the 1970s, the United States used molybdenum oxide instead of ferromolybdenum for alloying in steelmaking in industrial production; in the 1980s, Japan took the lead in conducting a large number of research on chromium ore smelting reduction and applied it to industrial production; Masahiro Kawakami Si and C were used to reduce powdered chromium ore on the induction furnace; Ida Yuki and others used coke to reduce chromium ore on the top-bottom double-blown converter; from the 1990s to the present, research on direct alloying has been carried out in China ; Gao Yunming and others simulated the direct alloying process of molybdenum oxide in the converter tapping process in the laboratory. Miao Zhimin and others used the direct alloying process of chrome ore when smelting GCr15 bearing steel in the 30t electric furnace of the No. 5 Plant of Shanghai Iron and Steel. When smelting steel 06VTi for enamel, vanadium slag was used instead of ferrovanadium for direct alloying in the converter. Jinan Iron and Steel Co., Ltd. used the method of spraying niobium concentrate in the 10t converter ladle to smelt niobium-containing low-alloy steel. The test results showed that Nb The recovery rate can reach more than 76%; but the essence of the above-mentioned direct alloying is to add the oxides of alloying elements in the converter steelmaking stage, and then use the reducing agent to reduce the oxides to elemental metals. process, but the oxide still needs to be obtained artificially, and when the oxide is added directly, because the density of the oxide is small, it will first float and slag, and often cannot fully contact and react with the reducing agent added later, so it does not really It is popularized and used in the production site. At the same time, conceptually, the existing direct alloying theory starts from the converter steelmaking, which is the middle stage of the whole smelting process, and the method of adding alloys to the material is mainly adding intermediate alloys, Pure metals or oxides are added in the converter stage and then reduced. However, due to the chemical properties of some elements such as rare earth elements are very active and easy to oxidize, they are very easy to be oxidized when artificially added, resulting in burning. Very low, and most of them exist in the form of oxides, and it is almost difficult to exert microalloying effect

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