Method for smelting ultra-low carbon steel with carbon lower than or equal to 20 PPm

Abstract

The invention discloses a method for smelting ultra-low carbon steel with carbon lower than or equal to 20 PPm. The method comprises the steps that molten iron desulphurization is conducted through pure magnesium and slaked lime, smelting in another furnace is conducted, high carbon ferromanganese is added according to high oxygen content; argon blowing is conducted; vacuum treatment is carried out inside a RH furnace; vacuum decarburization is conducted, a low-carbon refining agent is added to carry out desulfuration and slugging, and when the vacuum treatment is conducted for 15 min, aluminum balls are added; after recycling is conducted for 3 min, silicon iron, ferromanganese, a low-carbon desulfurizing agent are added immediately, and after the recycling is conducted for 5 min, the vacuum treatment is finished; the aluminum balls are sprinkled on the surface of steel slag, and after the total content of iron oxide and MnO in the slag is lower than 5.5 wt%, a later procedure is conducted. On the premise that the mechanical property of the ultra-low carbon steel is guaranteed, the carbon can be lower than or equal to 20 PPm, parts of low-carbon ferromanganese is replaced with parts of the high carbon ferromanganese, the carbon content is lower than 0.15 wt%, parts of slugging materials and parts of a deoxidizing agent are replaced with the low-carbon refining agent and the low-carbon desulfurizing agent, the cost can be lowered by at least 30 yuan per ton of steel, the smelting process is stable, and slagging is good in the refining process.

Description

technical field [0001] The invention relates to a method for smelting steel, in particular to a method for smelting ultra-low carbon steel with C≤20PPm. Background technique [0002] At present, the steel market is severe. Users not only require high-quality and easy-to-use steel products, but also require low prices. Sometimes 5 yuan / ton of steel of the same material can determine the user's buying and selling intentions. The market has forced the demand for steel production costs to be lower and more Well, the lower the production cost, the stronger the competitiveness of steel products, so it is imperative to widely use cheaper raw materials to replace more expensive raw materials in steel production. [0003] Smelting ultra-low carbon steel with carbon less than 0.002%. The principle of producing this steel is that alloys and raw materials with high carbon content cannot be added. The price of refined micro-carbon alloys and raw materials is often high, just like smeltin...

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Problems solved by technology

[0006] In the prior art, there is a practice of using high-carbon ferromanganese to replace low-carbon ferromanganese in the steel smelting process with a carbon content of 400-3000ppm, but there is no such thing as an ultra-low carbon steel with a carbon content of less than 20ppm. It has been used because people think that adding high-carbon ferromanganese instead of low-carbon ferromanganese will increase the carbon content of the steel, and it is difficult to control it below 20PPm. Therefore, all the more expensive low-carbon ferromanganese are used, resulting in increased production costs.

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