CN103555889A - Device and method for quickly removing occluded foreign substances in molten steel - Google Patents

Abstract

A method and device for quickly removing inclusions in molten steel relate to the field of high-quality steel production. The basic principle is to purify the molten steel by spraying high-purity argon gas at the bottom of the molten steel container and passing through a certain amount of specific ventilation elements arranged according to requirements to generate a large number of tiny bubble areas in the molten steel after primary refining or during refining Treatment, efficiently and quickly promotes the inclusions in molten steel to be captured and floated into the top slag to be removed. The device is composed of molten steel container (ladle or tundish) (1), multiple specific conical bottom blowing elements (2), protective bricks (6), bottom blowing gas regulating system (7), etc. The device has the functions of large coverage area of diffuse bubbles generated by bottom gas supply in molten steel, fast removal rate of inclusions, high gas utilization rate, and replaceability of specific gas supply components. Meet the needs of high-quality steel refining.

Description

Device and method for quickly removing inclusions in molten steel

technical field

The invention belongs to the technical field of steelmaking equipment, and in particular relates to a device and method for quickly removing inclusions in molten steel. Efficient and suitable for high-quality steel production.

Background technique

The size, quantity, distribution and type of inclusions in molten steel have a great influence on the quality of steel. Minimizing the number of various inclusions in molten steel has become one of the important efforts to improve the quality of molten steel. At present, the methods and devices of molten steel refining at home and abroad mainly include ordinary ladle bottom blowing argon, CAS/CAS-OB refining furnace, LF ladle refining furnace, RH vacuum circulation refining furnace, VD/VOD vacuum refining furnace, etc. These traditional refining furnaces remove steel The speed of inclusions in water is very slow, and the efficiency is not very high. Inclusions, especially small inclusions, are driven by air bubbles or liquid steel flow to float up to the interface between steel slag or molten steel and refractory materials in molten steel, and then absorbed by the slag at the top of molten steel or adhered to refractory materials in contact with molten steel. remove. In conventional refining devices such as ladle bottom blowing argon, CAS-OB refining device, LF refining furnace, VD/VOD vacuum refining, etc., the stirring movement of molten steel depends on bottom blowing argon, and single or double bottom blowing gas supply components are generally used. In order to prevent For secondary oxidation, generally the bottom blowing argon gas flow rate is relatively small, the bottom blowing gas supply element is single, the bubble diameter is relatively large and the number is small, and the bubble coverage area in the ladle is relatively small, so the inclusions in the molten steel, especially small inclusions, are more likely to be captured by the bubbles Smaller, some of the inclusions brought to the top slag or refractory surface by air bubbles and molten steel flow are easily rolled back into the interior of molten steel due to the action of liquid flow, making the removal speed and efficiency of molten steel inclusions relatively low. In order to obtain a better effect of removing inclusions, most refining devices and production processes rely on weak stirring or slow circulation of molten steel to remove inclusions in molten steel to the slag layer on the surface of molten steel, which makes the refining time very long and the temperature of molten steel drops. Larger, smelting cost and production rhythm are greatly affected. With the substantial increase in the demand for high-quality steel in modern industry and high-speed trains, ocean-going ships, and air transportation, the current traditional devices and methods for producing steel with ultra-low inclusion content can no longer meet the growing demand in terms of output and quality. Market needs.

Contents of the invention

The object of the present invention is to provide a device and method for quickly removing inclusions in molten steel, which can quickly and efficiently remove inclusions in molten steel, and is suitable for mass production of molten steel with a very low amount of inclusions, meeting the requirements for high-efficiency and low-cost production of high-quality steel.

The basic principle of the device and method for quickly removing inclusions in molten steel is to use the law of air bubbles adhering to inclusions and driving inclusions to float up, increasing the coverage area of fine air bubbles in molten steel, and greatly improving the speed and efficiency of removing inclusions.

The present invention arranges specific gas supply elements 2 at multiple positions at the bottom of the molten steel container 1, blows argon gas (inert gas) from the bottom to generate a large number of floating tiny bubbles in a large area of molten steel, and captures as many as possible in a short time The inclusions in the molten steel are taken to the slag at the top of the molten steel for removal, so as to achieve the purpose of quickly and efficiently removing inclusions and improving the quality of molten steel.

The device of the present invention includes: a container 1 for holding molten steel, a specific gas supply element 2, a protective brick 6, a bottom blowing gas regulating system 7, and the like. A specific gas supply element 2 is installed at the bottom of the molten steel container 1 to generate a wide range of dispersed micro-bubbles in the molten steel 3 to be processed by blowing inert gas from the bottom. The rising area 4 captures inclusions to the greatest extent through a large number of micro-bubbles distributed in the molten steel to promote its floating to the top slag 5 to be removed to purify the molten steel; a protective brick 6 is installed on the periphery of the specific gas supply element 2, and the bottom blowing gas regulating system 7 is connected to the specific gas supply element 2 through the pipeline 13 to control the flow rate of the bottom blowing gas .

The upper part of the specific air supply element 2 is made of refractory material (magnesia carbon, corundum, magnesium chromium, etc.) 10 and is covered with straight or curved micropores 11, the distance between the micropores 11 is 5-30mm, and the inner diameter is 0.5-1.5mm. The lower part distributes each micropore 11 air intake for the air chamber (12), and the air chamber is connected with the air intake pipe 13.

The specific air supply element 2 installed at the bottom of the molten steel container 1 has replaceability. During installation, the specific gas supply element 2 is inserted into the bottom of the pre-installed protective brick 6 through the outside of the molten steel container 1 . The diameter of the specific air supply element 2 at the bottom is 30-300mm, the number of 2 specific air supply elements is 3-24, and the edge spacing is greater than 100mm (note: only the minimum spacing is required in terms of life).

The method for quickly removing inclusions in molten steel of the present invention is to install a plurality of specific air supply elements 2 that can generate a large number of tiny bubbles at the bottom of the molten steel container 1 to avoid the nozzle area 8 and the molten steel impact area 9, and blow the inert gas through the bottom to be processed. A wide range of dispersed microbubbles 4 rises in the molten steel 3, and a large number of microbubbles distributed in the molten steel can capture inclusions to the greatest extent, and promote them to float up to the top slag 5 to be removed to purify the molten steel. The total flow rate of bottom blowing inert gas is 0.001-0.03m ³ /min per ton of molten steel. The bottom blowing flow rate of each specific air supply element is controlled individually or in combination.

The innovation of the present invention is:

A plurality of specific air supply elements 2 are installed at the bottom of the steel container 1 . During refining, inert gas is blown into the molten steel from the specific gas supply element 2 to generate a large number of tiny bubbles, forming a large-scale inclusion capture and removal zone in the molten steel in the steel container 1, effectively and quickly removing inclusions. In order to realize the maximum formation of micro-bubble coverage area in the molten steel of Shenggang container 1, a specific air supply element 2 with micro-air holes distributed at a certain distance is firstly designed. The diameter of the micro-air holes is 0.5-1.5mm, which can When blowing gas, prevent the molten steel from entering the tiny pores, and generate tiny bubbles in the molten steel when the gas is blown from the bottom. There is an air chamber 12 in the air inlet part of the specific gas supply element. The function of the air chamber is to evenly distribute the inert gas introduced from the outside into each tiny air hole. The micro air holes 11 inside the specific air supply element 2 have straight-through type and curved shape. type. The specific air supply elements 2 are evenly distributed in the positions arranged in the steel container 1 under the conditions of avoiding the nozzle area 8 and the impact area of the molten steel flow during tapping, and the interval between the specific air supply elements 2 is greater than 100mm, so that the small The bubble coverage area is as large as possible. During the production process, the air outlet surface of a specific air supply element 2 is severely agitated by molten steel, and its life is difficult to synchronize with other parts. Therefore, an online quick replacement method (hydraulic or electric or manual, etc.) After the end of the gas supply element 2 is severely damaged, it can be replaced quickly to ensure normal production. The bottom blowing flow rate of each specific air supply element 2 can be individually adjusted and controlled, or a plurality of specific air supply elements can be combined for adjustment.

The beneficial effects of the present invention are: adopting the device and method for removing inclusions in molten steel of the present invention can produce a wide range of micro-bubble molten steel purification areas in the steel container (1) for refining molten steel, and the removal speed of inclusions is fast High efficiency, the inclusion removal efficiency can reach 95% within 6-8 minutes, while ordinary bottom blowing argon needs more than 20-30 minutes to achieve this effect, the device and method of the present invention are conducive to efficient and rapid production of high-quality special steel .

Description of drawings

Figure 1 is a quick removal device for inclusions in molten steel.

Figure 2 shows a typical distribution of specific gas supply components.

Figure 3 shows the assembly of specific air supply elements and guard bricks.

In the figure: molten steel container 1, specific gas supply element 2, molten steel 3, dispersed micro-bubbles 4, top slag 5, brick protection 6, bottom blowing gas regulation system 7, nozzle 8, molten steel impact area 9, refractory material (magnesium carbon Quality, corundum quality, magnesium chromium, etc.) 10, straight or curved micropores 11, air chamber 12, intake pipe 13.

Detailed ways

The device of the present invention includes: a container 1 for holding molten steel, a specific gas supply element 2, a protective brick 6, a bottom blowing gas regulating system 7, and the like. A specific gas supply element 2 is installed at the bottom of the molten steel container 1 to generate a wide range of dispersed micro-bubbles in the molten steel 3 to be processed by blowing inert gas from the bottom. The rising area 4 captures inclusions to the greatest extent through a large number of micro-bubbles distributed in the molten steel to promote its floating to the top slag 5 to be removed to purify the molten steel; a protective brick 6 is installed on the periphery of the specific gas supply element 2, and the bottom blowing gas regulating system 7 is connected to the specific gas supply element 2 through the pipeline 13 to control the flow rate of the bottom blowing gas .

At the bottom of the ladle, under the condition of avoiding the nozzle 8 area and the molten steel impact area 9, 11 specific air supply elements 2 are evenly distributed, which can prevent the life of the specific air supply element from being too short, and make the nozzle 8 no longer Scoured by the liquid steel flow, at the same time, the widest possible range of molten steel micro-bubble purification zone is formed in the ladle to the greatest extent, which greatly improves the removal rate and efficiency of inclusions in the molten steel. A protective brick 6 is installed on the periphery of the specific air supply element 2, which not only protects the specific air supply element 2, but also prevents the bottom from being damaged when the specific air supply element 2 is seriously damaged and needs to be replaced. After the converter or electric arc furnace is smelted and the steel is tapped, when performing alloying, initial deoxidation, deep deoxidation and desulfurization operations on molten steel, first pass through one or two specific gas supply elements 2 at a gas flow rate of 0.008m3/min per ton of molten steel. Stir the molten steel for 6 minutes, mix the composition and temperature of the molten steel, and promote the reaction of steel slag, and then use all specific air supply elements 2 installed through the bottom of the bag, and the bottom blowing flow rate of each specific air supply element 2 is 0.001m3/min per ton of molten steel The gas is blown in to generate a large amount of tiny bubbles, and the molten steel is purified for 10 minutes to quickly reduce the inclusions in the molten steel to meet the requirements of high-quality steel. , only a large number of micro-bubble groups are produced, the agitation of molten steel is weak, the interface of steel slag is very stable, and the exposure of molten steel on the surface of slag is very small, so the temperature drop of molten steel is also very small.

Claims (5)

1. the quick removal device of inclusion content in melting steel, is characterized in that: comprising: contain steel in water container (1), specific gas supply element (2), protect brick (6), bottom blown gas regulation system (7); Containing steel in water container (1) bottom installation specific gas supply element (2), by bottom blowing rare gas element, in processed molten steel (3), produce large-scale fine bubble (4) rising area, by being distributed in a large number farthest capture clip foreign material of micro-bubble in molten steel, promote it to float in top slag (5) and be removed and purify hot metal; Specific gas supply element (2) periphery is provided with protects brick (6), and bottom blown gas regulation system (7) is connected with specific gas supply element (2) by pipeline (13), controls Bottom Blowing Gas Flow Rate size.

Described specific gas supply element (2) top is that refractory materials (10) is covered with straight-through or crooked micropore (11), micropore (11) spacing 5-30mm internal diameter 0.5-1.5mm; Bottom is that air chamber (12) distributes each micropore (11) air inlet, and air chamber is connected with inlet pipe (13).

2. device as claimed in claim 1, is characterized in that: described specific gas supply element (2) is arranged on contains steel in water container (1) bottom, and avoids mouth of a river district (8) and molten steel impact zone (9).

3. device as claimed in claim 1 or 2, is characterized in that: when specific gas supply element (2) is installed, by containing steel in water container (1) lateral pre-installation, have the bottom of protecting brick (6) to insert specific gas supply element (2); Bottom specific gas supply element (2) diameter is 30-300mm, and specific gas supply element (2) number is 3-24, and limit portion spacing is greater than 100mm.

4. device as claimed in claim 1, is characterized in that: described refractory materials (10) is magnesium carbonaceous, corundum or magnesium chromium.

5. the method that an inclusion content in melting steel is removed fast, it is characterized in that: in Sheng steel in water container (1) bottom, avoid mouth of a river district (8) and molten steel impact zone (9) a plurality of specific gas supply elements (2) that can produce a large amount of micro-bubbles are installed, by bottom blowing rare gas element, in processed molten steel (3), produce large-scale fine bubble (4) rising area, by being distributed in a large number farthest capture clip foreign material of micro-bubble in molten steel, promote it to float in top slag (5) and be removed and purify hot metal; Bottom blowing rare gas element total gas flow rate is molten steel 0.001-0.03m per ton ³/ min, each specific gas supply element bottom blowing flow adopts alone or in combination to be controlled.

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