A method for tapping a ladle with air blowing and sand drainage

Abstract

The present application relates to a kind of blowing upper row drainage sand's steel ladle tapping method, belong to steelmaking technical field.The stages such as slide plate equipment preparation, additional drainage sand, molten steel injection, blowing sand, tapping etc., the blowing sand is carried out before tapping, and the blown gas is inert gas.The present application uses slide plate blowing before tapping, and the upper sintering layer is broken through the gap of lower drainage sand, solves the problem that drainage sand is not opened, and the self-opening rate approaches 100%.Blowing agitation makes drainage sand into molten steel, and floats to steel slag under the action of buoyancy, eliminates the pollution hazard of drainage sand.

Description

Technical Field

[0001] This invention relates to a ladle casting method for blowing air to discharge and guide sand, belonging to the field of steelmaking technology. Background Technology

[0002] The ladle nozzle is a device that controls the flow rate of molten steel and plays a crucial role in the steelmaking process. The smooth opening of the nozzle during pouring is a key condition for successful casting. Common methods for opening the nozzle include air blowing, oxygen burning, and packing methods; electromagnetic induction heating has also been researched. Air blowing and electromagnetic induction heating methods heat and agitate the molten steel in contact with the nozzle to prevent condensation and blockage at the nozzle; however, these methods require complex equipment and their effectiveness is unpredictable. The oxygen burning method involves melting condensed molten steel by burning oxygen to open the nozzle; this method is unsafe and unstable, and is only used in emergency situations. Currently, most steel casting employs a combination of guide sand and sliding nozzles for opening the nozzle. The basic principle is to pre-fill the ladle nozzle with diverting sand. After the converter tapps, the high-temperature molten steel and the diverting sand come into contact and form a sintered layer, becoming a "hard shell." When the ladle is opened for casting, the slide gate opens, and the unsintered diverting sand at the bottom flows out first. Then, the "hard shell" near the molten steel is broken through under the static pressure of the molten steel, and the molten steel flows out. However, the use of diverting sand can also allow inclusions to enter the molten steel in the tundish, contaminating it. These inclusions are difficult to remove in subsequent processes, especially affecting the quality of high-quality steel. The sintered layer formed by the diverting sand in the upper part of the nozzle is difficult to control in terms of thickness. If it is too thick, it reduces the self-opening rate and can cause continuous casting machine failure. Although many improvements have been made to the quality and addition method of diverting sand, these problems have not yet been effectively solved. Therefore, it is necessary to study a ladle casting method using diverting sand that can avoid the influence of diverting sand on the quality of cast steel and improve the casting rate during casting. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for opening the steel ladle for blowing air and discharging the guiding sand, which can avoid the influence of the guiding sand on the quality of the steel casting and improve the opening rate during casting.

[0004] The technical solution of this invention is: a method for pouring steel in a ladle using air blowing and sand discharge, comprising stages such as slide plate equipment preparation, sand discharge installation, molten steel injection, air blowing and sand discharge, and pouring commencement; the operation steps are as follows:

[0005] ① Skateboard equipment preparation: Assemble the air-blowing skateboard mechanism on the steel ladle and install the breathable skateboard;

[0006] ② Add diversion sand: Add diversion sand into the ladle nozzle;

[0007] ③ Pouring molten steel: Transport the ladle to the tapping position and pour in molten steel;

[0008] ④ Air blowing and sand removal: Connect the air blowing slide mechanism to inert gas, and blow inert gas into the nozzle through the air-permeable slide. The gas is blown through the gap of the guide sand to the sintered sand layer in contact with the molten steel, blowing open the sintered sand layer, and the guide sand is blown into the molten steel and floats to the ladle slag.

[0009] ⑤ Start pouring: Open the air blowing slide mechanism to start pouring, and then stop blowing.

[0010] As described above, in the ladle casting method of blowing air to discharge the guide sand, the gas flow rate at the beginning of blowing the sand is 200-500 L / min, and the blowing continues for 30-80 seconds. After the sintered sand layer is blown open and the guide sand is blown out of the water outlet and floats to the surface, the gas flow rate is adjusted to 30-100 L / min and the blowing continues until casting begins.

[0011] In the above-described ladle casting method for blowing air to discharge and guide sand, the inert gas is argon.

[0012] In the ladle pouring method described above for blowing air to remove sand, the blowing air to remove sand is carried out before pouring.

[0013] As described above, the ladle pouring method for blowing sand upwards and discharging it begins before the ladle is moved to the pouring position. After the sand is blown into the molten steel and floats to the surface, the ladle is moved to the pouring position and pouring begins.

[0014] As described above, the ladle pouring method for blowing sand upwards and discharging it begins after the ladle is turned into the pouring position, and the sand is blown into the molten steel and floats to the surface before pouring begins.

[0015] In the above-described method for pouring sand into a ladle by blowing air upwards, the lower slide plate is a ventilated slide plate. When the air blowing slide plate mechanism is in the closed position, the air outlet of the lower slide plate vent is opposite to the upper slide plate sprue and the ladle sprue.

[0016] The beneficial effects of this invention are as follows: By using a sliding plate to blow air before casting, the upper sintered layer is opened through the gaps in the lower guide sand, solving the problem of the guide sand not opening on its own, with a self-opening rate approaching 100%. The air blowing and stirring cause the guide sand to enter the molten steel, where it floats to the steel slag under buoyancy, eliminating the pollution hazards caused by the guide sand. This method is simple to operate, requires little equipment investment, is easy to implement, and has promotional value. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to specific embodiments.

[0018] The application of this technology will be introduced as an example on a steelmaking production line equipped with a 150t converter-LF-continuous casting machine. Example 1

[0019] A method for pouring molten steel in a ladle using air blowing and sand removal includes stages such as slide plate equipment preparation, sand removal, molten steel injection, air blowing and sand removal, and pouring commencement. The operation steps are as follows:

[0020] ①Preparation of the skateboard equipment: Install the air-blowing skateboard mechanism and the ventilated skateboard on the ladle; the ventilated skateboard is the lower skateboard. When the air-blowing skateboard mechanism is in the closed position, the air outlet of the lower skateboard vent is opposite to the upper skateboard sprue and the ladle sprue.

[0021] ② Add diversion sand: Hoist the prepared steel ladle to the sand adding site, and use a special sand adding device to add diversion sand into the ladle nozzle from above;

[0022] ③ Injecting molten steel: Before tapping from the converter, the ladle with added sand is transported to the tapping position, and the molten steel from the converter is injected into the ladle;

[0023] ④ Gas blowing and sand removal: After the ladle is placed on the continuous casting ladle turret and the hydraulic cylinder of the sliding plate mechanism is installed, the gas blowing pipe on the sliding plate mechanism is connected to the pre-installed argon gas pipeline. The steel in this furnace has only undergone LF refining. It is expected that 78 minutes will pass from the tapping of the converter to the start of casting in the ladle. The ladle water inlet is the continuous water inlet. 1.5 minutes before the ladle is transferred, the argon gas valve is opened to start blowing argon gas. The flow rate is controlled at 200L / min and the blowing is continued for 80 seconds (the gas blows open the sintered sand layer in contact with the molten steel through the gap of the guide sand, and blows the guide sand into the molten steel and floats to the ladle slag). The gas flow rate is adjusted to 30L / min and the blowing continues.

[0024] ⑤ Start pouring: Move the ladle to the pouring position on time, install the ladle long nozzle, open the ladle slide plate device to start pouring, and close the argon valve to stop blowing argon.

[0025] After pouring began, the slag in the continuous casting ladle was inspected, and no diversion sand was found. After pouring was completed, the slag residue in the ladle was inspected, and diversion sand was found.

[0026] This example demonstrates that by blowing air through the ventilated slide plate before casting, the upper sintered layer can be pushed open through the gaps in the lower guide sand, solving the problem of the guide sand not opening on its own and ensuring the self-opening rate. At the same time, blowing air through the ventilated slide plate can also blow the guide sand into the molten steel and make it float to the steel slag, eliminating the pollution hazards of the guide sand. Example 2

[0027] A method for pouring molten steel in a ladle using air blowing and sand removal includes stages such as slide plate equipment preparation, sand removal, molten steel injection, air blowing and sand removal, and pouring commencement. The operation steps are as follows:

[0028] ①Preparation of the skateboard equipment: Install the air-blowing skateboard mechanism and the ventilated skateboard on the ladle; the ventilated skateboard is the lower skateboard. When the air-blowing skateboard mechanism is in the closed position, the air outlet of the lower skateboard vent is opposite to the upper skateboard sprue and the ladle sprue.

[0029] ② Add diversion sand: Hoist the prepared steel ladle to the sand adding site, and use a special sand adding device to add diversion sand into the ladle nozzle from above;

[0030] ③ Injecting molten steel: Before tapping from the converter, the ladle with added sand is transported to the tapping position, and the molten steel from the converter is injected into the ladle;

[0031] ④ Gas blowing and sand removal: After the ladle is placed on the continuous casting ladle turret and the hydraulic cylinder of the sliding plate mechanism is installed, the gas blowing pipe on the sliding plate mechanism is connected to the pre-installed argon gas pipeline. The steel in this furnace has undergone LF+RH double refining. It is expected that it will take 121 minutes from the time the steel is tapped from the converter to the time the ladle is opened for casting. The water inlet of the ladle is the continuous water inlet. One minute before the ladle is turned on, the argon gas valve is opened to start blowing argon gas. The flow rate is controlled at 500L / min and the blowing is continued for 30 seconds (the gas blows open the sintered sand layer in contact with the molten steel through the gap of the guide sand. The guide sand is blown into the molten steel and floats to the ladle slag). The gas flow rate is adjusted to 100L / min and the blowing continues.

[0032] ⑤ Start pouring: Move the ladle to the pouring position on time, install the ladle long nozzle, open the ladle slide plate device to start pouring, and close the argon valve to stop blowing argon.

[0033] After pouring began, the slag in the continuous casting ladle was inspected, and no diversion sand was found. After pouring was completed, the slag residue in the ladle was inspected, and diversion sand was found.

[0034] This example demonstrates that by blowing air through the ventilated slide plate before casting, the upper sintered layer can be pushed open through the gaps in the lower guide sand, solving the problem of the guide sand not opening on its own and ensuring the self-opening rate. At the same time, blowing air through the ventilated slide plate can also blow the guide sand into the molten steel and make it float to the steel slag, eliminating the pollution hazards of the guide sand. Example 3

[0035] A method for pouring molten steel in a ladle using air blowing and sand removal includes stages such as slide plate equipment preparation, sand removal, molten steel injection, air blowing and sand removal, and pouring commencement. The operation steps are as follows:

[0036] ①Preparation of the skateboard equipment: Install the air-blowing skateboard mechanism and the ventilated skateboard on the ladle; the ventilated skateboard is the lower skateboard. When the air-blowing skateboard mechanism is in the closed position, the air outlet of the lower skateboard vent is opposite to the upper skateboard sprue and the ladle sprue.

[0037] ② Add diversion sand: Hoist the prepared steel ladle to the sand adding site, and use a special sand adding device to add diversion sand into the ladle nozzle from above;

[0038] ③ Injecting molten steel: Before tapping from the converter, the ladle with added sand is transported to the tapping position, and the molten steel from the converter is injected into the ladle;

[0039] ④ Gas blowing and sand removal: After the ladle is placed on the continuous casting ladle swivel table and the hydraulic cylinder of the sliding plate mechanism is installed, the gas blowing pipe on the sliding plate mechanism is connected to the pre-installed argon gas pipeline. The steel in this furnace has only undergone RH refining. It is expected that 75 minutes will pass from the time the steel is tapped from the converter to the time the ladle is ready for casting. The ladle water inlet is the continuous water inlet. The ladle is rotated to the casting position on time, the ladle long water inlet is installed, the argon gas valve is opened and argon gas is blown in. The flow rate is controlled at 300L / min and the gas is blown in continuously for 30 seconds (the gas blows open the sintered sand layer in contact with the molten steel through the gap of the guide sand, and the guide sand is blown into the molten steel and floats to the ladle slag). The gas flow rate is adjusted to 100L / min and the gas blowing continues.

[0040] ⑤ Start pouring: Open the ladle slide device to start pouring, and close the argon gas valve to stop blowing argon gas.

[0041] After pouring began, the slag in the continuous casting ladle was inspected, and no diversion sand was found. After pouring was completed, the slag residue in the ladle was inspected, and diversion sand was found.

[0042] This example demonstrates that by blowing air through the ventilated slide plate before casting, the upper sintered layer can be pushed open through the gaps in the lower guide sand, solving the problem of the guide sand not opening on its own and ensuring the self-opening rate. At the same time, blowing air through the ventilated slide plate can also blow the guide sand into the molten steel and make it float to the steel slag, eliminating the pollution hazards of the guide sand. Example 4

[0043] A method for pouring molten steel in a ladle using air blowing and sand removal includes stages such as slide plate equipment preparation, sand removal, molten steel injection, air blowing and sand removal, and pouring commencement. The operation steps are as follows:

[0044] ①Preparation of the skateboard equipment: Install the air-blowing skateboard mechanism and the ventilated skateboard on the ladle; the ventilated skateboard is the lower skateboard. When the air-blowing skateboard mechanism is in the closed position, the air outlet of the lower skateboard vent is opposite to the upper skateboard sprue and the ladle sprue.

[0045] ② Add diversion sand: Hoist the prepared steel ladle to the sand adding site, and use a special sand adding device to add diversion sand into the ladle nozzle from above;

[0046] ③ Injecting molten steel: Before tapping from the converter, the ladle with added sand is transported to the tapping position, and the molten steel from the converter is injected into the ladle;

[0047] ④ Gas blowing and sand removal: After the ladle is placed on the continuous casting ladle swivel table and the hydraulic cylinder of the sliding plate mechanism is installed, the gas blowing pipe on the sliding plate mechanism is connected to the argon gas pipeline that has been installed in advance. The steel in this furnace has only undergone LF refining. It is expected that 76 minutes will pass from the tapping of the converter to the start of casting in the ladle. The ladle nozzle is a new nozzle. The ladle is rotated to the start of casting on time, the ladle long nozzle is installed, the argon gas valve is opened and argon gas is blown in. The flow rate is controlled at 500L / min and the gas is blown in continuously for 30 seconds (the gas blows open the sintered sand layer in contact with the molten steel through the gap of the guide sand, and the guide sand is blown into the molten steel and floats to the ladle slag). The gas flow rate is adjusted to 30L / min and the gas blowing continues.

[0048] ⑤ Start pouring: Open the ladle slide device to start pouring, and close the argon gas valve to stop blowing argon gas.

[0049] After pouring began, the slag in the continuous casting ladle was inspected, and no diversion sand was found. After pouring was completed, the slag residue in the ladle was inspected, and diversion sand was found.

[0050] This example demonstrates that by blowing air through the ventilated slide plate before casting, the upper sintered layer can be pushed open through the gaps in the lower guide sand, solving the problem of the guide sand not opening on its own and ensuring the self-opening rate. At the same time, blowing air through the ventilated slide plate can also blow the guide sand into the molten steel and make it float to the steel slag, eliminating the pollution hazards of the guide sand.

Claims

1. A ladle casting method for blowing air to discharge and guide sand, characterized in that: The process includes preparing the skateboard equipment, adding diversion sand, injecting molten steel, blowing air to remove sand, and starting the casting process. The operation steps are as follows: ① Skateboard equipment preparation: Assemble the air-blowing skateboard mechanism on the steel ladle and install the breathable skateboard; ② Add diversion sand: Add diversion sand into the ladle nozzle; ③ Pouring molten steel: Transport the ladle to the tapping position and pour in molten steel; ④ Air blowing and sand removal: The air blowing slide mechanism is connected to inert gas. Inert gas is blown into the nozzle through the air-permeable slide. The gas is blown through the gaps in the guide sand to the sintered sand layer in contact with the molten steel, blowing open the sintered sand layer and blowing the guide sand into the molten steel, where it floats to the ladle slag. The air blowing and sand removal begins before the ladle is moved to the pouring position. After the guide sand is blown into the molten steel and floats to the surface, the ladle is moved to the pouring position and pouring begins. The air blowing and sand removal is carried out before pouring begins. ⑤ Start casting: Open the air blowing slide mechanism to start casting, and then stop blowing; The initial gas flow rate for blowing sand is 200-500 L / min, and the blowing continues for 30-80 seconds. After the sintered sand layer is blown open and the guiding sand is blown out of the water outlet and floats to the surface, the gas flow rate is adjusted to 30-100 L / min and the blowing continues until the pouring begins.

2. The ladle casting method for blowing and discharging sand as described in claim 1, characterized in that: The inert gas is argon.

3. The ladle casting method for blowing air and discharging sand as described in claim 1, characterized in that: The ventilated slide plate is the lower slide plate. When the air blowing slide plate mechanism is in the closed position, the vent holes of the lower slide plate are opposite to the sprue nozzles and ladle nozzles of the upper slide plate.