Method for smelting low-carbon stainless steel by utilizing GOR converter

Abstract

The invention discloses a method for smelting low-carbon stainless steel by utilizing a GOR converter. The method is characterized in that eight bottom guns are used in the GOR converter, the eight bottom guns are symmetrically distributed on the bottom of the GOR converter in a shape like a Chinese character 'jing' and basically coincide with an impact area for blowing oxygen by top guns, so thatthe bottom blowing flow is increased, the mixing efficiency of a molten pool is improved, meanwhile, the impact of the oxygen blown by the top guns is utilized to suppress the problem that the bottomblowing flow is too large to cause air flow to break through the molten pool, and strong decarburization capability is realized; then, through reasonable oxygen, argon / nitrogen ratio and flow distribution in the decarburization stage, a certain proportion of mixed oxygen and nitrogen (or argon) are blown in the dynamic decarburization stage through bottom blowing, so that the partial pressure ofCO in the molten pool is controlled, C in the molten pool is oxidized prior to Cr, decarburization efficiency is improved, Cr oxidation is reduced, and C can reach about 0.010% at the GOR end point and even lower, and the Cr2O3 content in reduced slag is controlled within 2%, so that the GOR converter can economically and stably produce medium-high chromium stainless steel with the C content lowerthan 0.030%.

Description

technical field [0001] The invention relates to a stainless steel smelting process, in particular to a method for smelting low-carbon stainless steel using a GOR converter. Background technique [0002] The existing low-carbon stainless steel smelting technologies mainly include the following types: [0003] 1) AOD furnace smelting method [0004] This technology controls the ratio of oxygen and side blown gas by side blowing mixed gas, and uses the strong gas supply capacity of AOD side blowing to control the C content in the stainless steel molten pool at about 0.0100%, achieving the purpose of producing low carbon stainless steel. [0005] 2) VOD vacuum method [0006] Put the molten stainless steel in the ladle, put the ladle in the vacuum tank, use the vacuum pump to make the ladle in a relatively vacuum state, use the vacuum to reduce the partial pressure of CO in the ladle, and achieve the goal of decarburization and chromium preservation. C can be reduced to below...

AI Technical Summary

Problems solved by technology

The bottom blowing mode of GOR converter is different from the side blowing mode of AOD. Usually, 3 to 5 GOR converter bottom blowing guns are installed, and the flow rate is limited by the depth of the molten pool. In order to prevent the bottom blowing flow from being too large, the breakdown of the molten pool cannot be reached. Good kinetic conditions lead to a decrease in smelting effect, and a large amount of Cr oxidation occurs during decarburization in the low-carbon area, resulting in low alloy yield and high cost. At the same time, more ferrosilicon is required for reduction, resulting in carbon increase , cannot produce low-carbon stainless steel stably and at low cost

Therefore, it is usually only used to produce stainless steel with a carbon content higher than 0.030%, especially when the stainless steel Cr content is greater than 16%, it is more difficult to produce

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