CN-122012843-A - Control method for reducing burning loss of acid-soluble aluminum in refining furnace

CN122012843ACN 122012843 ACN122012843 ACN 122012843ACN-122012843-A

Abstract

The invention discloses a control method for reducing acid-soluble aluminum burning loss of a refining furnace, and belongs to the technical field of carbon steel smelting. The method comprises two working procedures of converter smelting and LF refining. The converter process is characterized in that the end point [ C ] is controlled to be 0.04-0.1%, the end point slag FeO is less than or equal to 20%, tapping slag is washed, the temperature of an argon blowing station is ensured to be more than or equal to 1550 ℃ and the acid-soluble aluminum is ensured to be more than or equal to 0.01%, and low oxygen potential molten steel is provided for LF refining. The LF procedure is controlled step by step, namely, firstly adding a slag former and carrying out strong stirring (bottom blowing flow 2800-3200L/min) for preliminary deoxidation, then heating and roughly adjusting the aluminum content to 0.030-0.040%, secondly carrying out strong stirring to enable FeO in slag to be less than 1.0%, and finally, secondarily finely adjusting the aluminum content to 0.030-0.035%, wherein the refining period is more than or equal to 40min, and the soft blowing is more than or equal to 6min. The invention realizes the whole process accurate control of molten steel oxygen potential and slag steel reaction through systematic cooperation of the front and back working procedures, stably controls the acid-soluble aluminum burning loss within 100ppm, and remarkably improves the purity of molten steel and the sheet yield.

Inventors

Yu Yueshan
HAN SHUDONG
QI ZHENGWEI
ZHAI YOUYOU
YANG XINLONG
MA SHANGJUN
ZHANG JUNTONG

Assignees

甘肃酒钢集团宏兴钢铁股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260305

Claims (8)

1. The control method for reducing the burning loss of acid-soluble aluminum in the refining furnace is characterized by comprising a converter smelting process and an LF refining process, and comprises the following specific steps: (1) Converter smelting process: Controlling the carbon content of molten steel at the end point of converter blowing to be 0.04-0.1%, wherein the FeO content in the end point slag is less than or equal to 20%; lime is added in the tapping process for slag washing; After tapping of the converter, the entering temperature of molten steel in an argon blowing station is more than or equal to 1550 ℃, and the acid-soluble aluminum content Al in the molten steel in the argon blowing station is more than or equal to 0.01%; (2) LF refining procedure: slag-making stirring, namely adding lime and a slab top slag modifier after LF (ladle furnace) enters a station, and then carrying out double-line bottom argon blowing stirring, wherein the total bottom blowing flow is 2800-3200L/min, and the stirring time is 1-3min; A primary temperature rising stage, namely carrying out primary temperature rising slag melting operation, and adjusting alloy according to the molten steel components of an argon blowing station to control the acid-soluble aluminum content of the molten steel to be 0.030-0.040%; The slag melting and stirring stage comprises the steps of controlling the temperature of molten steel to be more than or equal to 1550 ℃ after the primary temperature rising and slag melting are finished, and then carrying out secondary double-line bottom blowing argon stirring, wherein the total bottom blowing flow is 2800-3200L/min, and the stirring time is 1-3min, so that the FeO content in slag is less than 1.0%; A secondary aluminum preparation stage, namely secondarily adjusting alloy according to the molten steel components after primary temperature rising and slag melting, so that the acid-soluble aluminum content of the molten steel is controlled to be 0.030-0.035%; and (3) outbound, namely carrying out calcium treatment and titanium alloying before outbound, and carrying out soft blowing treatment after outbound, wherein the soft blowing time is more than or equal to 6min.
2. The control method for reducing the burning loss of acid-soluble aluminum in a refining furnace according to claim 1, wherein in the converter smelting process, the tapping temperature is controlled to 1600-1650 ℃.
3. The control method for reducing burning loss of acid-soluble aluminum in a refining furnace according to claim 1, wherein the lime is added in an amount of 2.3-3.9 Kg/ton of molten steel during tapping in the converter smelting process.
4. The method for controlling the refining furnace to reduce the burning loss of acid-soluble aluminum according to claim 1, wherein in the converter smelting process, silicomanganese and aluminum steel grit are added for deoxidization during tapping, wherein the aluminum steel grit has an Al content of 75% and the silicomanganese has an Si content of 18.8%.
5. The method for controlling the refining furnace to reduce the burning loss of acid-soluble aluminum according to claim 1, wherein in the slag-making stirring step of the LF refining process, lime and a slab top slag modifier are added, and fluorite is added, wherein the addition amount of lime is 4.5-7.8 Kg/ton of molten steel, the addition amount of the slab top slag modifier is 0.6-0.8 Kg/ton of molten steel, and the addition amount of fluorite is 0.4-0.8 Kg/ton of molten steel.
6. The method for controlling a refining furnace to reduce burning loss of acid-soluble aluminum according to claim 1, wherein coarse adjustment of the acid-soluble aluminum content of molten steel is performed by using aluminum iron in a primary temperature rising stage of the LF refining process, and the Al content of the aluminum iron is 42%.
7. The control method for reducing burning loss of acid-soluble aluminum in a refining furnace according to claim 1, wherein the binary basicity of slag is >5.0 after the end of the slag stirring stage of the LF refining process.
8. The control method for reducing the burning loss of acid-soluble aluminum in a refining furnace according to claim 1, wherein in the secondary aluminum distribution stage of the LF refining process, aluminum wires are used to perform secondary adjustment of the acid-soluble aluminum content of molten steel.

Description

Control method for reducing burning loss of acid-soluble aluminum in refining furnace Technical Field The invention relates to the technical field of carbon steel smelting, in particular to a control method for reducing acid-soluble aluminum burning loss of a refining furnace. Background The acid-soluble aluminum can be combined with nitrogen in steel to form AlN particles, so that the effects of refining grains and improving the strength and toughness of the steel are achieved. However, during the smelting process of aluminum killed steel, acid-soluble aluminum in molten steel is extremely easily oxidized, resulting in burning loss of aluminum. Excessive aluminum burn-out not only results in reduced alloy yield and increased cost, but also is more critical in the formation of a large amount of Al 2O3 inclusions. The aggregation of these inclusions at grain boundaries can become a source of cracks, and at the same time affect the fluidity of the molten steel, increasing the risk of surface cracks (such as cluster cracks, center cracks) of the slab during solidification and rolling, severely affecting product quality and yield. In the prior art, fluctuation exists in oxygen content control of molten steel at the smelting end point of a converter, so that the oxygen potential of the molten steel entering a refining furnace (LF) is unstable. In the LF refining process, if slag melting is insufficient and slag oxidizing property (such as FeO content) is too high, oxidation burning loss of acid-soluble aluminum in molten steel is increased, so that the acid-soluble aluminum content in a final finished product is difficult to accurately control, and the quantity of Al 2O3 inclusions is increased. Therefore, how to systematically control the whole smelting process, effectively reduce the burning loss of acid-soluble aluminum in the refining link, and is a key technical problem for improving the purity and the product quality of aluminum killed steel. Disclosure of Invention Aiming at the problems of large acid-soluble aluminum burning loss and low molten steel purity caused by improper control of the smelting process in the prior art, the invention provides a control method for systematically reducing the acid-soluble aluminum burning loss. The method aims to realize stable control of acid-soluble aluminum burning loss (generally within 100 ppm) by optimizing process connection and key parameter control of converter and LF refining, thereby improving molten steel purity and sheet yield. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a control method for reducing burning loss of acid-soluble aluminum in a refining furnace comprises two core processes of converter smelting and LF refining. The first step of converter smelting is to provide low oxygen potential and clean molten steel for subsequent LF refining. Controlling the carbon content of molten steel at the smelting end point of the converter to be within the range of 0.04-0.1%, and controlling the FeO content of the slag sample at the end point to be less than or equal to 20%. This operation aims at controlling the carbon oxygen deposit, reducing the free oxygen content in the molten steel and reducing the source of oxidizing nature from the source. During tapping of the converter, lime (the addition amount is 2.3-3.9 Kg/ton molten steel) is added for slag washing under the strong stirring action of the steel flow. This can realize efficient desulfurization and adsorption of some inclusions in the molten steel. After tapping by the converter, the molten steel enters an argon blowing station for treatment. The entering temperature of the argon blowing station is required to be more than or equal to 1550 ℃ so as to ensure that enough heat is generated in the follow-up LF procedure to carry out slag melting operation. Meanwhile, the silicon manganese and the aluminum steel grit are added for pre-deoxidation during tapping, so that the content Al of acid-soluble aluminum in molten steel in an argon blowing station is more than or equal to 0.01%, and the oxygen potential of the molten steel is further reduced. Wherein the Al content of the steel grit aluminum is 75 percent, and the Si content of the silicomanganese is 18.8 percent. The tapping temperature of the converter is controlled to be 1600-1650 ℃ so as to ensure the entering temperature requirement of an argon blowing station. And secondly, LF refining, wherein the step is to realize full slag melting, stable slag system and finally accurate control of the core of acid-soluble aluminum. Slag stirring, namely after LF enters a station, lime (4.5-7.8 Kg/ton of molten steel) and a plate blank top slag modifier (0.6-0.8 Kg/ton of molten steel) are added at first (an appropriate amount of fluorite can be added simultaneously to facilitate smelting). And then immediately starting double-line bottom blowing argon to carry out strong stirring, wherein the total b