Method for improving proportion of residual manganese at end point of converter

Abstract

The invention provides a method for increasing the proportion of residual manganese at the end point of a converter. The method comprises the following steps: controlling the temperature of molten iron entering the converter to be more than or equal to 1350-1380 DEG C, the C content of the molten iron to be more than or equal to 4.5%, the Si content of the molten iron to be less than or equal to 0.5% and the Mn content of the molten iron to be less than or equal to 0.45%, and ensuring that Mn / Si is controlled In the blowing process, low-gun high-pressure operation is adopted in the early stage; medium-low gun and medium-pressure cooperative control is adopted in the middle stage; adjusting slag by adopting a high gun and medium and high pressure in the later stage; therefore, it is guaranteed that the proportion of residual manganese in molten steel at the end point is stably controlled to be 55%-65% on the whole, the proportion of the residual manganese in the molten steel is increased by 10%-15%, the content of the residual manganese is increased by 0.043%-0.065%, the content of the residual manganese is increased to 0.24%-0.28%, and the cost of per ton of steel is reduced by 4.96 yuan / t to 7.5 yuan / t; and the end point molten steel C is increased by 0.02%, the end point slag TFe is reduced by about 2%, and the Mn alloy yield is increased by 2.7%.

Description

technical field [0001] The invention relates to the technical field of converter steelmaking, in particular to a method for increasing the residual manganese ratio at the end point of the converter. Background technique [0002] Manganese is an important alloying element in steel. During the converter blowing process, most of the manganese element is oxidized into the slag, and then a large amount of silicon-manganese alloy must be added in the tapping process or refining to meet the requirements of the steel composition. The residual manganese content at the end of the converter is affected by many factors, and its level reflects the level of converter smelting technology and operation level. Increasing the residual manganese mass fraction of the molten steel at the converter end point is an important means to reduce the amount of manganese alloy used in the converter process, reduce the cost of steelmaking, and improve the market competitiveness of steel products. The dec...

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Problems solved by technology

[0004] In a patented control method for increasing the residual manganese content at the end point of the converter: the loading amount of the converter is 63-67 tons of molten iron, 6-8 tons of scrap steel, the amount of lime added is 50-70kg / t, and the end point temperature is 1650-1670°C. High iron ratio smelting is conducive to rapid temperature rise in the early stage, shortens the transition time between Si and C oxidation transition periods, and reduces the medium-term reduction ratio, but this patented method is not suitable for smelting in medium and low iron ratios to increase the proportion of residual manganese

A patented method for increasing the residual manganese content of molten steel at the end of the converter: Low-carbon steel and high-carbon steel are smelted using low-P molten iron with P≤0.075%, and a high-iron ratio loading mode of 101t molten iron + 6t scrap steel, which is conducive to rapid temperature rise in the early stage. Shorten the transition time between Si and C oxidation transition periods, reduce the medium-term reduction ratio, and low-P hot metal smelting can weaken the difficulty and pressure of de-P in the slag system, and help to ensure the proportion of residual manganese, but this patented method is not suitable for medium and low Increase the proportion of residual manganese in smelting under the condition of molten iron ratio

Therefore, the above two patents are for increasing the residual manganese at the end point of the converter in the high iron ratio smelting mode, and are not suitable for the improvement and guarantee of the end point residual manganese under the conditions of medium and low iron ratios, etc.

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