JP7258381B2 - Method for improving RH refining effect using hydrogen gas - Google Patents

Description

The present invention belongs to the technical field of iron and steel metallurgy, and relates to a method for improving RH refining effect using hydrogen gas.

The RH smelting furnace was originally a single degassing device, and has been developed to date as a refining device having various metallurgical functions such as decarburization, degassing, temperature control, and inclusion removal.

However, the conventional RH refining process has the following problems.

There is a large temperature drop in the RH refining process. If the molten steel temperature is too low during continuous casting, nozzle clogging is likely to occur, casting is interrupted, and defects such as slag entrainment and cracks are likely to occur on the surface of the cast slab. The conventional method raises the temperature with an aluminum exothermic agent, which tends to deteriorate the cleanliness of the molten steel.

The evolution of RH refining and decarburization technology has become highly functional, but with the continuous progress of science and technology, people continue to demand that the carbon content be lowered. There is a problem that the carbon content does not reach the standard.

The RH refining system promotes molten steel agitation by driving the circulatory flow of the molten steel and enhances the removal of inclusion collision, polymerization and growth. However, the removal rate of inclusions in the steel is remarkably reduced in the latter stage of RH refining, making it difficult to achieve deep removal of inclusions.

At present, it is also mentioned that the above technical problem is solved by spraying hydrogen gas, but it is difficult to grasp the timing of spraying hydrogen gas. For example, in "improving the decarburization rate of ultra-low carbon steel in the RH degassing apparatus by the hydrogen gas blowing method" and "manufacturing ultra-low carbon steel by blowing hydrogen gas to RH", the timing of blowing hydrogen gas is the latter stage of the decarburization process, and the reaction between the hydrogen gas and the dissolved oxygen in the molten steel and the secondary combustion heat radiation with the top-blown oxygen gas in the vacuum chamber both raise the temperature of the molten steel. At the same time, it is clear that it is not conceivable to promote decarburization end oxygen, reduce the amount of deoxidizing agent used, and reduce the number of deoxidation products in steel, but dissolved hydrogen will later become inclusions. In the process of removing inclusions, it is possible to generate a large amount of fine bubbles dispersed with inclusions as nuclei in steel. is very high, and deep removal of inclusions can be achieved.

In order to solve this technical problem, the present invention is realized by using hydrogen gas, blowing the hydrogen gas as rising gas instead of argon onto the riser, and controlling the timing of switching the rising gas from hydrogen gas to argon. be.

In the present invention, there is a large temperature drop in the RH refining process, the carbon content of the produced steel does not reach the standard, the speed of removing inclusions in the steel is slow in the latter stage of RH refining, and the removal of inclusions is deep. We try to solve the technical problem that it is difficult to effectively perform

Means to solve the problem

In order to solve the above technical problems, the present invention aims to raise the temperature of molten steel, promote decarburization, promote the floating of inclusions, improve the cleanliness of molten steel, replace some argon, and reduce refining costs. Second, hydrogen gas is used as the ascending gas instead of argon during RH refining, vacuum decarburization is performed, the ascending gas is switched to argon, vacuum degassing and inclusion removal are performed, and finally aluminum is added to deoxidize. To provide a method for improving the RH refining effect using hydrogen gas.

During the RH refining, hydrogen gas is used as the ascending gas instead of argon, and heat is released by the reaction between the hydrogen gas and dissolved oxygen in the molten steel and secondary combustion with the top-blown oxygen gas in the vacuum chamber, and the molten steel temperature is reduced to 2 to 2. It is preferable to raise the temperature by 10° C. and reduce the amount of aluminum exothermic agent used by 8 to 40 kg.

In the vacuum decarburization, it is preferable that the hydrogen in the vacuum tank promotes reaction kinetics between carbon and oxygen in the steel and the decarburization rate by 5% to 20% by dispersing fine hydrogen bubbles precipitated in the molten steel. .

Switching the rising gas to argon preferably occurs after 10-25 minutes of vacuum decarburization or when decarburization is fully completed.

The vacuum degassing is to desorb hydrogen dissolved in molten steel by vacuum treatment, and the removal of inclusions generates dispersed microbubbles with inclusions as nuclei in molten steel when desorbing dissolved hydrogen, and the microbubbles collide. It is preferable to capture the inclusions in the steel, promote the polymerization growth of the inclusions, promote the removal of floating inclusions, and reduce the total oxygen content by 10% to 35%.

Step 1: lifting the RH refiner ladle such that the RH refiner riser and the RH refiner downcomer are inserted into the molten steel of the RH refiner ladle after the ladle truck travels to the molten steel receiving location;
Step 2: Blowing hydrogen gas rising gas into the RH refiner riser by means of the RH riser air blower, at the same time activating the vacuum system and evacuating to raise the liquid level of the molten steel;
Step 3: Selecting whether top-blown oxygen is required and the amount of top-blown oxygen gas based on the initial carbon content and oxygen content of the molten steel entering the RH treatment station;
Step 4: If oxygen blowing is required, the RH smelter vacuum chamber balance will top-blown oxygen. If blowing is not required, increasing the vacuum degree of the RH vacuum chamber after 3 to 5 minutes to perform vacuum decarburization;
Step 5: After 10-25 minutes of vacuum decarburization, switching the ascending gas to argon and degassing by vacuum treatment to remove inclusions;
Step 6: After decarburization is completed, add aluminum to deoxidize, continue vacuum treatment for 5-20 minutes, break vacuum to complete vacuum treatment;
is preferably included.

The flow rate for blowing hydrogen gas from the RH refining apparatus riser to the molten steel is 50 to 300 m ³ /h, and it is preferable to reduce the amount of argon used as the rise gas by 64 to 143 m ³ .

Preferably, it comprises two heat dissipation zones and an inclusion removal zone, one of which is a decarburization heat dissipation zone near the surface of the molten steel, and the other is a heat dissipation zone near the tip of the RH refining apparatus riser in the two heat dissipation zones. .

The degree of vacuum in step 2 is preferably 5 to 15 Kpa, and the degree of vacuum in step 4 is preferably 67 Pa.

After the decarburization in step 6 is completed, the dissolved oxygen is 98-200 ppm, 8-20 kg of aluminum is added to deoxidize, the vacuum treatment is continued for 5 minutes, the vacuum is broken to complete the vacuum treatment, and the end Preferably the carbon is 0.0006-0.0009% and the total oxygen content is reduced to 6.3-8.5 ppm.

The above technical contents provided by the embodiments of the present invention have at least the following beneficial effects.
(1) The present invention uses hydrogen gas as the ascending gas instead of argon during RH refining, and the reaction between the hydrogen gas and dissolved oxygen in the molten steel and secondary combustion heat radiation with the oxygen gas blown upward in the vacuum chamber increase the temperature of the molten steel. increase
(2) The present invention accelerates the reaction kinetics between carbon and oxygen in the steel by dispersing fine hydrogen bubbles that hydrogen precipitates in the molten steel in the vacuum chamber, and the reaction between the dissolved hydrogen and dissolved oxygen in the steel promotes desorption. It lowers carbon end oxygen, reduces the amount of oxygen scavengers used, and reduces the number of deoxidation products in the steel.
(3) In the present invention, after decarburization for a certain period of time, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is removed by vacuum treatment. When dissolved hydrogen is desorbed, dispersed microbubbles are generated with inclusions as nuclei in molten steel, and the microbubbles collide to trap inclusions in the steel, promote the polymerization growth of inclusions, and remove the floatation of inclusions. promote

In order to explain the technical content in the embodiments of the present invention more clearly, the drawings necessary for the description of the embodiments are briefly described below, and the drawings described below are only some embodiments of the present invention. , it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without further creative effort.

FIG. 1 is a schematic diagram of the method for improving the RH refining effect using hydrogen gas according to the present invention.

In order to make the technical problems, technical contents and advantages to be solved by the present invention clearer, the detailed description is given below with reference to the drawings and specific embodiments.

In order to raise the temperature of the molten steel, promote decarburization, promote the floating of inclusions, improve the cleanliness of the molten steel, partially replace argon, and reduce the refining cost, the present invention uses argon instead of argon during RH refining. use hydrogen gas as rising gas to perform vacuum decarburization, switch the rising gas to argon, perform vacuum degassing and inclusion removal, and finally add aluminum to deoxidize, RH refining using hydrogen gas Suggest ways to improve effectiveness.

In particular, hydrogen gas is used as the ascending gas instead of argon during the RH refining, heat is released by the reaction between the hydrogen gas and dissolved oxygen in the molten steel and secondary combustion with the top-blown oxygen gas in the vacuum chamber, and the molten steel temperature is increased. The temperature is raised by 2 to 10°C, and the amount of aluminum exothermic agent used is reduced by 8 to 40 kg.

In particular, the vacuum decarburization accelerates the reaction kinetics of carbon and oxygen in the steel by dispersing fine hydrogen bubbles, which are precipitated in the molten steel by hydrogen in the vacuum tank, and increases the decarburization rate by 5% to 20%.

Specifically, switching the rising gas to argon occurs after 10-25 minutes of vacuum decarburization or when decarburization is fully completed.

In particular, the vacuum degassing is to desorb hydrogen dissolved in molten steel by vacuum treatment, and the removal of inclusions generates dispersed microbubbles with inclusions as nuclei in molten steel when the dissolved hydrogen is desorbed. It collides and traps inclusions in the steel, promotes the polymerization growth of inclusions, promotes the removal of inclusions' floatation, and reduces the total oxygen content by 10% to 35%.

In particular, step 1: lifting the RH refiner ladle such that the RH refiner riser and the RH refiner downcomer are inserted into the molten steel of the RH refiner ladle after the ladle truck travels to the molten steel receiving location. and,
Step 2: Blowing hydrogen gas rising gas into the RH refiner riser by means of the RH riser air blower, at the same time activating the vacuum system and evacuating to raise the liquid level of the molten steel;
Step 3: Selecting whether top-blown oxygen is required and the amount of top-blown oxygen gas based on the initial carbon content and oxygen content of the molten steel entering the RH treatment station;
Step 4: If oxygen blowing is required, the RH smelter vacuum chamber balance will top-blown oxygen. If blowing is not required, increasing the vacuum degree of the RH vacuum chamber after 3 to 5 minutes to perform vacuum decarburization;
Step 5: After 10-25 minutes of vacuum decarburization, switching the ascending gas to argon and degassing by vacuum treatment to remove inclusions;
Step 6: After decarburization is completed, add aluminum to deoxidize, continue vacuum treatment for 5-20 minutes, break vacuum to complete vacuum treatment;
including.

In particular, the flow rate of the hydrogen gas blowing from the RH refining apparatus riser to the molten steel is 50-300 m ³ /h, which reduces the amount of argon used as the rise gas by 64-143 m ³ .

In particular, it includes two heat dissipation zones and an inclusion removal zone, one of which is a decarburization heat dissipation zone near the molten steel surface and the other is a heat dissipation zone near the tip of the RH refiner riser.

In particular, the degree of vacuum in step 2 is 5 to 15 Kpa, and the degree of vacuum in step 4 is 67 Pa.

In particular, after the decarburization in step 6 is completed, the dissolved oxygen is 98-200 ppm, 8-20 kg of aluminum is added to deoxidize, the vacuum treatment is continued for 5 minutes, and the vacuum is broken to complete the vacuum treatment. , the end carbon is 0.0006-0.0009% and the total oxygen content is reduced to 6.3-8.5 ppm.

Specifically, a method for improving the RH refining effect using hydrogen gas will be described in combination with the following examples and drawings.

A 150tRH refining unit in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C, the actual temperature of the molten steel entering the RH treatment station is 1610°C, and the initial temperature of the molten steel entering the RH treatment station is 1630°C. The carbon content is 0.038%, the initial oxygen content of molten steel entering the RH treatment station is 550 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Oxygen is blown by the apparatus vacuum chamber balance 1, blowing 94 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 98 ppm, and 10 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0008%.

Within the refining cycle, the molten steel temperature is increased by 6℃, the total oxygen content is reduced to 6.5ppm, the decarburization rate is improved by 5%-20%, the total argon consumption is reduced by ^125m3 , and the aluminum consumption is is reduced by 28 kg.

A 120tRH refining unit in a steel mill in China requires an initial temperature of 1630°C for molten steel entering the RH treatment station, and the actual temperature of molten steel entering the RH treatment station is 1612°C. The initial carbon content is 0.04%, the initial oxygen content of molten steel entering the RH treatment station is 532 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Oxygen is blown by the apparatus vacuum chamber balance 1, and 85 m ³ of oxygen are blown. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 110 ppm, and 8 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0007%.

Within the refining cycle, the molten steel temperature is increased by 8℃, the total oxygen content is reduced to 7.8ppm, the decarburization rate is improved by 5%~20%, the total amount of argon used is reduced by ^102m3 , and the amount of aluminum used. is reduced by 23 kg.

A 150tRH refining unit in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.045%, the initial oxygen content of molten steel entering the RH treatment station is 523 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Oxygen is blown by the apparatus vacuum chamber balance 1, blowing 99 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 23 minutes, the ascending gas is switched to argon, and hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refiner ascender 7, and the RH refiner descender 4, and the RH refiner descender 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 124 ppm, and 10 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0006%.

Within the refining cycle, the molten steel temperature is increased by 8℃, the total oxygen content is reduced to 8.5ppm, the decarburization rate is improved by 5%~20%, the total argon consumption is reduced by ^115m3 , and the aluminum consumption is is reduced by 28 kg.

A 150tRH refining equipment in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.042%, the initial oxygen content of molten steel entering the RH treatment station is 520 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Oxygen is blown by the apparatus vacuum chamber balance 1, blowing 115 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 18 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refiner ascender 7, and the RH refiner descender 4, and the RH refiner descender 4. Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 100 ppm, and 10 kg of aluminum is added to deoxidize.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0007%.

Within the refining cycle, the molten steel temperature is increased by 6℃, the total oxygen content is reduced to 7.8ppm, the decarburization rate is improved by 5%~20%, the total argon consumption is reduced by ^95m3 , and the aluminum consumption is is reduced by 23 kg.

A 150tRH refining equipment in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.038%, the initial oxygen content of molten steel entering the RH treatment station is 580 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Blow oxygen by means of the apparatus vacuum chamber balance 1, blow 59 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 110 ppm, and 10 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0008%.

Within the refining cycle, the molten steel temperature is increased by 8℃, the total oxygen content is reduced to 7.2ppm, the decarburization rate is improved by 5%~20%, the total argon consumption is reduced by ^103m3 , and the aluminum consumption is is reduced by 26 kg.

A 150tRH refining equipment in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.038%, the initial oxygen content of molten steel entering the RH treatment station is 570 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Blow oxygen by means of the apparatus vacuum chamber balance 1, blow 105 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 200 ppm, and 20 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0009%.

Within the refining cycle, the molten steel temperature is raised by 9℃, the total oxygen content is lowered to 8.1ppm, the decarburization rate is improved by 5%-20%, the total argon consumption is reduced by ^105m3 , and the aluminum consumption is is reduced by 18 kg.

A 150tRH refining equipment in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.035%, the initial oxygen content of molten steel entering the RH treatment station is 550 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Oxygen is blown by the apparatus vacuum chamber balance 1, blowing 70 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 15 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 100 ppm, and 10 kg of aluminum is added to deoxidize.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0009%.

Within the refining cycle, the molten steel temperature is increased by 5℃, the total oxygen content is reduced to 7.7ppm, the decarburization rate is improved by 5%~20%, the total argon consumption is reduced by ^80m3 , and the aluminum consumption is is reduced by 25 kg.

A 120tRH refining unit in a steel mill in China requires an initial temperature of 1630°C for molten steel entering the RH treatment station, and the actual temperature of molten steel entering the RH treatment station is 1610°C. The initial carbon content is 0.032%, the initial oxygen content of molten steel entering the RH treatment station is 610 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 200 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Blow oxygen by means of the apparatus vacuum chamber balance 1, blow 37 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 100 ppm, and 8 kg of aluminum is added for deoxidization.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0007%.

Within the refining cycle, the molten steel temperature is increased by 5℃, the total oxygen content is reduced to 6.9ppm, the decarburization rate is improved by 5%-20%, the total argon consumption is reduced by ^64m3 , and the aluminum consumption is is reduced by 20 kg.

A 150tRH refining equipment in a steel mill in China requires that the initial temperature of molten steel entering the RH treatment station is 1630°C. The initial carbon content is 0.044%, the initial oxygen content of molten steel entering the RH treatment station is 480 ppm, and the target carbon content is 0.001%.

As shown in FIG. 1, the ladle truck raises the RH refining ladle 8 to a predetermined immersion depth after traveling to the molten steel receiving location.

The RH riser air blowing device 6 has a flow rate of 300 m ³ /h of H ₂ blown into the RH vacuum chamber 2 by the RH refining device riser 7. At the same time, the vacuum system is started to evacuate to 8000 Pa to perform RH refining. Blow oxygen by means of the apparatus vacuum chamber balance 1, blow 104 m ³ of oxygen. Here, in the heat dissipation region 5, a heat dissipation reaction mainly occurs between the hydrogen gas and dissolved oxygen in the molten steel. In the decarburization heat dissipation region 3, mainly hydrogen bubbles are generated to promote the reaction kinetics of carbon and oxygen, and secondary combustion mainly of hydrogen gas and top-blown oxygen gas occurs.

After the top-blown oxygen is completed, the degree of vacuum in the RH vacuum chamber 2 is raised to a final degree of vacuum of 67 Pa, and vacuum decarburization is further performed.

After decarburizing for 20 minutes, the ascending gas is switched to argon, and the hydrogen dissolved in the molten steel is escaped by vacuum processing in the RH vacuum chamber 2, the RH refining apparatus ascending pipe 7, and the RH refining apparatus descending pipe 4, and the RH refining equipment descending pipe 4 Inclusion removal area 9 removes inclusions.

After decarburization is completed, the dissolved oxygen reaches 100 ppm, and 10 kg of aluminum is added to deoxidize.

The vacuum treatment is continued for 5 minutes and the vacuum is broken to complete the vacuum treatment. End carbon is 0.0007%.

Within the refining cycle, the molten steel temperature is increased by 8℃, the total oxygen content is reduced to 6.3ppm, the decarburization rate is improved by 5%-20%, the total argon consumption is reduced by ^143m3 , and the aluminum consumption is reduced. is reduced by 30 kg.

It can be seen from the above that the above technical content provided by the embodiments of the present invention has at least the following beneficial effects.

The present invention uses hydrogen gas as rising gas instead of argon during RH refining to realize temperature compensation of molten steel during RH refining, ensure continuous casting forward, and effectively prevent nozzle nodules. At the same time, it reduces the amount of aluminum exothermic agent used and improves the cleanliness of molten steel. Hydrogen in the vacuum chamber accelerates the reaction kinetics of carbon and oxygen in the steel by dispersing fine hydrogen bubbles precipitated in the molten steel. Dispersed micro-bubbles generated in molten steel with inclusions as nuclei during desorption of dissolved hydrogen promote the removal of inclusions. The amount of aluminum deoxidizing agent used after decarburization is reduced to reduce the number of deoxidizing interventions. Using hydrogen gas instead of argon also reduces manufacturing costs.

The above are the preferred embodiments of the present invention, and various modifications and changes are possible for those skilled in the art without departing from the above-described principles of the present invention, and these modifications and changes should also be regarded as the protection scope of the present invention. It should be pointed out that

1 RH Refiner Vacuum Chamber Balance 2 RH Vacuum Chamber 3 Decarburization Heat Dissipation Zone 4 RH Refiner Downcomer 5 Heat Dissipation Zone 6 RH Riser Air Blower 7 RH Refiner Upcomer 8 RH Refiner Ladle 9 Inclusion Removal Zone.

Claims (10)

Hydrogen gas is used instead of argon during RH refining in order to raise the temperature of the molten steel, promote decarburization, promote the floating of inclusions, improve the cleanliness of the molten steel, partially replace argon, and reduce refining costs. using hydrogen gas as the ascending gas, performing vacuum decarburization, switching the ascending gas to argon, performing vacuum degassing and inclusion removal, and finally deoxidizing by adding aluminum. A method for improving the RH refining effect. During the RH refining, hydrogen gas is used as the ascending gas instead of argon, and heat is released by the reaction between the hydrogen gas and dissolved oxygen in the molten steel and secondary combustion with the top-blown oxygen gas in the vacuum chamber, and the molten steel temperature is reduced to 2 to 2. The method for improving the RH refining effect using hydrogen gas according to claim 1, characterized in that the temperature is raised by 10°C and the amount of exothermic agent used for aluminum is reduced by 8 to 40 kg. The vacuum decarburization is characterized by accelerating the reaction kinetics between carbon and oxygen in the steel and increasing the decarburization rate by 5% to 20% by dispersing fine hydrogen bubbles that are precipitated in the molten steel. The method for improving the RH refining effect using hydrogen gas according to claim 1. RH refining effect using hydrogen gas according to claim 1, characterized in that switching the rising gas to argon occurs after vacuum decarburization for 10-25 minutes or when decarburization is completely completed how to improve The vacuum degassing is to desorb hydrogen dissolved in molten steel by vacuum treatment, and the removal of inclusions generates dispersed microbubbles with inclusions as nuclei in molten steel when desorbing dissolved hydrogen, and the microbubbles collide. It captures inclusions in the steel, promotes polymerization growth of inclusions, promotes removal of floating inclusions, and reduces the total oxygen content by 10% to 35%. A method for improving RH refining efficiency using the described hydrogen gas. Step 1: lifting the RH refiner ladle such that the RH refiner riser and the RH refiner downcomer are inserted into the molten steel of the RH refiner ladle after the ladle truck travels to the molten steel receiving location;
Step 2: Blowing hydrogen gas rising gas into the RH refiner riser by means of the RH riser air blower, at the same time activating the vacuum system and evacuating to raise the liquid level of the molten steel;
Step 3: Selecting whether top-blown oxygen is required and the amount of top-blown oxygen gas based on the initial carbon content and oxygen content of the molten steel entering the RH treatment station;
Step 4: If oxygen blowing is required, the RH smelter vacuum chamber balance will top-blown oxygen. If blowing is not required, increasing the vacuum degree of the RH vacuum chamber after 3 to 5 minutes to perform vacuum decarburization;
Step 5: After 10-25 minutes of vacuum decarburization, switching the ascending gas to argon and degassing by vacuum treatment to remove inclusions;
Step 6: After decarburization is completed, add aluminum to deoxidize, continue vacuum treatment for 5-20 minutes, break vacuum to complete vacuum treatment;
A method for improving RH refining effect using hydrogen gas according to any one of claims 1 to 5, comprising: 7. The method according to claim 6, characterized in that the flow rate of hydrogen gas sprayed from the RH refining apparatus riser to the molten steel is 50 to 300 m ³ /h, and the amount of argon used as the rise gas is reduced by 64 to 143 m ³ . A method for improving the RH refining effect using hydrogen gas. It comprises two heat dissipation zones and an inclusion removal zone, wherein one of the two heat dissipation zones is a decarburization heat dissipation zone near the surface of the molten steel, and the other is a heat dissipation zone near the tip of the RH refining device riser pipe. The method for improving the RH refining effect using hydrogen gas according to claim 6. The method for improving the RH refining effect using hydrogen gas according to claim 6, characterized in that the degree of vacuum in step 2 is 5 to 15 Kpa, and the degree of vacuum in step 4 is 67 Pa. After the decarburization in step 6 is completed, the dissolved oxygen is 98-200 ppm, 8-20 kg of aluminum is added to deoxidize, the vacuum treatment is continued for 5 minutes, the vacuum is broken to complete the vacuum treatment, and the end Improve the RH refining effect using hydrogen gas according to claim 6, characterized in that the carbon is 0.0006-0.0009% and the total oxygen content is reduced to 6.3-8.5 ppm Method.

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