CN111545718A - Method and device for blowing argon in slab continuous casting - Google Patents
Method and device for blowing argon in slab continuous casting Download PDFInfo
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- CN111545718A CN111545718A CN202010394783.1A CN202010394783A CN111545718A CN 111545718 A CN111545718 A CN 111545718A CN 202010394783 A CN202010394783 A CN 202010394783A CN 111545718 A CN111545718 A CN 111545718A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
- B22D11/117—Refining the metal by treating with gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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Abstract
The invention discloses a method for blowing argon in slab continuous casting, which comprises the following steps: preheating argon to 300-800 ℃; in the slab continuous casting process, blowing the preheated argon into a stopper rod, a tundish water feeding port and a crystallizer submerged nozzle respectively, and monitoring the temperature of the preheated argon; according to the monitoring result, argon flow of the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is respectively adjusted; the flow rate of the argon gas is 1 to 7 NL/min. The invention also provides a device for blowing argon in slab continuous casting, which comprises: the heating pipeline is used for preheating argon; the stopper rod argon blowing branch pipe is used for conveying argon to the stopper rod; the argon blowing branch pipe is used for conveying argon to the tundish; an immersed water gap argon blowing branch pipe of the crystallizer is used for conveying argon; the heating pipeline is embedded in the tundish cover body. The area ratio of the inclusions in the casting blank is reduced by 5-10 ppm, and the proportion of the liquid level fluctuation of the crystallizer within +/-3 is improved by 5-15%.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a method and a device for continuously casting and blowing argon to a slab.
Background
Inert gas-argon gas can all be blown into at stopper stick head, pouring basket upper nozzle and crystallizer immersion nozzle inner wall to the slab continuous casting in-process, and its purpose mainly has two aspects: 1) the method can prevent the impurities in the molten steel from adhering and gathering on the inner walls of the stopper rod head, the tundish water feeding port and the crystallizer submerged nozzle to form blockage; 2) meanwhile, fine argon bubbles can capture impurities in the molten steel floating process, and the molten steel purification effect is achieved. Argon is an inert gas, is blown into molten steel, does not participate in chemical reaction, is not dissolved, contains little hydrogen, nitrogen, oxygen and the like, and can be considered as a small vacuum chamber for the gas dissolved in the molten steel, and the partial pressure of other gases in the small bubbles is almost zero. The gas, impurities and the like in the molten steel continuously diffuse into the argon bubbles, collide and adhere to the argon bubbles and are removed along with the escape of the argon bubbles.
In the traditional process, normal temperature argon is directly blown into a stopper rod head, a tundish upper nozzle and the inner wall of a crystallizer submerged nozzle through a conveying pipeline, normal temperature argon bubbles rapidly expand by 6-10 times in volume at the temperature of molten steel (1530-1600 ℃), the bubbles collide with each other in the volume expansion process to further increase the volume of a single bubble, the adsorption and removal effect of large bubbles on molten steel inclusions in the floating process is limited, and meanwhile, when the large bubbles pass through the interface of protective slag on the surface of the crystallizer and molten steel, liquid level fluctuation is easily caused to cause slag entrapment.
Therefore, how to better remove the removing effect of the fine inclusions and reduce the fluctuation of the liquid level of the crystallizer caused by argon blowing is always a key research problem of metallurgical workers.
Disclosure of Invention
The invention aims to provide a method and a device for blowing argon in slab continuous casting, wherein the area ratio of inclusions in a casting blank is reduced by 5-10 ppm, the proportion of liquid level fluctuation within +/-3 of a crystallizer is improved by 5-15%, and the degradation rate of a high-end automobile outer plate is reduced by 10-30%.
In order to achieve the above object, the present invention provides a method for blowing argon in slab continuous casting, the method comprising:
preheating argon to 300-800 ℃;
in the slab continuous casting process, blowing the preheated argon into a stopper rod, a tundish water feeding port and a crystallizer submerged nozzle respectively, and monitoring the temperature of the preheated argon;
according to the monitoring result, argon flow of the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is respectively adjusted; the flow rate of the argon gas is 1 to 7 NL/min.
Further, the method for preheating argon comprises the following steps: the inlet of a heating pipeline embedded in the tundish cover body is connected into an argon gas supply pipeline through a quick-change connector, and the argon gas in the heating pipeline is heated by utilizing radiant heat in the tundish baking process and the molten steel pouring process.
Further, the dynamically controlling the flow rate of the argon gas according to the measured temperature of the argon gas specifically comprises:
when the preheating temperature of argon is 300-500 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 1-3, 1-3 and 1-2 NL/min;
when the preheating temperature of argon is 500-700 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 3-4.5, 3-5 and 2-3 NL/min;
when the preheating temperature of argon is 700-800 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 4.5-5.5, 5-7 and 3-4 NL/min.
Further, the preheating temperature of the argon gas is detected every 5-10 minutes, and the flow of the argon gas is dynamically controlled according to the measured temperature of the argon gas.
Further, the method is suitable for the tundish of 40-80 tons. The method is suitable for all steel grades and continuous casting machines with the continuous casting machine pulling speed of 0.8-1.7 m/min.
The invention provides a device for continuously casting a slab and blowing argon, which comprises:
the heating pipeline is used for preheating argon;
the stopper rod argon blowing branch pipe is used for conveying argon to the stopper rod;
the argon blowing branch pipe is used for conveying argon to the tundish;
the submerged nozzle argon blowing branch pipe of the crystallizer is used for conveying argon to the crystallizer;
the heating pipeline is embedded in the tundish cover body and is provided with an outlet and an inlet for connecting an argon supply pipeline;
one end of the stopper rod argon blowing branch pipe is communicated with an outlet of the heating pipeline, and the other end of the stopper rod argon blowing branch pipe is communicated with the inside of the stopper rod;
one end of the tundish upper nozzle argon blowing branch pipe is communicated with an outlet of the heating pipeline, and the other end of the tundish upper nozzle argon blowing branch pipe is communicated with the tundish upper nozzle;
one end of the submerged nozzle argon blowing branch pipe of the crystallizer is communicated with an outlet of the heating pipeline, and the other end of the submerged nozzle argon blowing branch pipe of the crystallizer is communicated with the submerged nozzle of the crystallizer.
Furthermore, the end of one end of the argon blowing branch pipe of the stopper rod, which is communicated with the stopper rod, is downward and is aligned with the inside of the stopper rod;
the end of one end of the tundish upper nozzle argon blowing branch pipe communicated with the tundish upper nozzle is downwards aligned with the tundish upper nozzle;
the end of one end of the submerged nozzle argon blowing branch pipe of the crystallizer, which is communicated with the submerged nozzle of the crystallizer, is downwards aligned with the upper nozzle of the tundish.
Further, the inlet of the heating pipeline is connected to an argon gas supply pipeline through a quick-change connector.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
according to the method and the device for blowing argon in slab continuous casting, provided by the invention, argon is preheated, the temperature of the argon is measured in the whole process, and then the flow of the argon is dynamically controlled to be 1-7 NL/min according to the measured temperature of the argon; the argon bubble is heated and expanded in the molten steel when argon is blown at normal temperature in the traditional continuous casting process, and the volume is increased by 6-10 times. And the higher the temperature after the argon gas is preheated, the smaller the volume expansion after the argon gas enters molten steel, the smaller the influence on the liquid level fluctuation of the crystallizer, the higher the temperature is, the larger the argon blowing flow is, the removal of fine inclusions is facilitated, the occurrence of water gap blockage is prevented, and meanwhile, the influence on the liquid level fluctuation can be obviously reduced when the liquid level surface layer of the crystallizer overflows. By adopting the method, the area ratio of the inclusions in the casting blank is reduced by 5-10 ppm, the proportion of the liquid level fluctuation of the crystallizer within +/-3 is improved by 5-15%, and the degradation rate of the high-end automobile outer plate is reduced by 10-30%.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a block diagram of an apparatus for continuously casting slab and blowing argon according to an embodiment of the present invention;
FIG. 2 is a side view of the internal structure of an apparatus for continuously casting slab and blowing argon according to an embodiment of the present invention;
1. an argon gas supply line; 2. heating the pipeline; 2-1, an inlet of a heating pipeline; 2-2, an outlet of the heating pipeline; 3. a tundish cover body; 4. a stopper rod hole; 5. a temperature measuring charging hole; 6. a water feeding hole of the tundish; 7. a stopper rod blows an argon branch pipe; 8. an argon blowing branch pipe is arranged at the water feeding port of the tundish; 9. an immersion nozzle argon blowing branch pipe of the crystallizer;
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the embodiment of the invention provides the following general ideas:
on one hand, the embodiment of the invention provides a method for blowing argon in slab continuous casting, which comprises the following steps:
step 1, preheating argon.
According to the step, the heating expansion of argon bubbles in molten steel during the conventional continuous casting argon blowing at normal temperature can be reduced, and the volume is increased by 6-10 times. And after the argon is preheated, the higher the temperature is, the smaller the volume expansion is after entering molten steel, and the smaller the influence on the liquid level fluctuation of the crystallizer is.
Preferably, the temperature of the argon gas after preheating the argon gas is 300-800 ℃; the preheated argon temperature is less than 300 ℃ which does not play a role in reducing liquid level fluctuation, and the cost required for the preheated argon temperature is more than 800 ℃ is too high. The device that the above-mentioned slab continuous casting argon that blows is preferably adopted to this embodiment carries out radiant heating to the argon gas, and the heat energy in the middle of the make full use of pouring basket toasts the in-process and the molten steel pouring process need not extra cost input.
The argon flow is dynamically controlled according to the temperature after the argon is preheated, the higher the temperature is, the larger the argon blowing flow is, the removal of fine inclusions is facilitated, the occurrence of water gap blockage is prevented, and meanwhile, the influence on liquid level fluctuation can be remarkably reduced when the liquid level surface layer of the crystallizer overflows. However, if the flow rate of the argon gas is less than 1NL/min, the effect of removing fine particles cannot be achieved; if the flow rate of argon gas is more than 7NL/min, many bubbles appear, increasing the fluctuation of the liquid level.
The stopper rod blows argon to enable argon bubbles to enter the steel flow in the SEN, the flowing state and the flowing speed of the molten steel in the water port can be adjusted, and Al is reduced2O3The accumulation on the inner wall of the water gap avoids the rising of a stopper rod caused by the blockage of the water gap, and reduces the generation of large-scale impurities; the argon film formed on the inner wall of the upper nozzle by blowing argon from the upper nozzle prevents Al in molten steel2O3The impurities are adhered to the water feeding port; meanwhile, the argon bubbles can effectively change the smoothness in the crystallizer, promote impurities to float upwards, further purify molten steel and improve the liquid level stability. Improper argon blowing can cause fluctuation of the liquid level of the crystallizer.
The argon blowing of the tundish water feeding port is to form a uniform argon film around the inner wall of the water feeding port so as to prevent or reduce the adhesion of impurities on the inner wall of the water feeding port and further reduce the reduction and the blockage of the inner diameter of the water feeding port. Once the water feeding port is blocked, the flow control of the stopper rod fluctuates, so that the fluctuation of the liquid level of the crystallizer is increased. Therefore, the argon flow among the stopper, the tundish upper nozzle and the crystallizer submerged nozzle is adaptive.
More preferably, the inventor finds out through a large number of experiments that the liquid level fluctuation can be reduced to the maximum extent and the removal of fine inclusions can be increased by dynamically controlling the flow rate of the argon gas according to the temperature of the argon gas.
The dynamic control of the argon flow according to the measured argon temperature specifically comprises the following steps:
when the preheating temperature of argon is 300-500 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 1-3, 1-3 and 1-2 NL/min; if the argon flow of the stopper rod is less than 1NL/min, the effect of removing fine particles cannot be achieved, and if the argon flow of the stopper rod is more than 3NL/min, a plurality of bubbles can appear, so that the fluctuation of the liquid level is increased; if the argon flow of the water feeding port of the tundish is less than 1NL/min, the effect of removing fine particles cannot be achieved, if the argon flow is more than 3NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased; if the argon flow of a submerged nozzle of the crystallizer is less than 1NL/min, the effect of removing fine particles cannot be achieved, and if the argon flow is more than 2NL/min, a plurality of bubbles can appear, and the fluctuation of the liquid level is increased;
when the preheating temperature of argon is 500-700 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 3-4.5, 3-5 and 2-3 NL/min; if the argon flow of the stopper rod is less than 3NL/min, the effect of removing fine particles cannot be achieved, if the argon flow of the stopper rod is more than 4.5NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased; if the argon flow of the water feeding port of the tundish is less than 3NL/min, the effect of removing fine particles cannot be achieved, if the argon flow is more than 5NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased; if the argon flow of a submerged nozzle of the crystallizer is less than 2NL/min, the effect of removing fine particles cannot be achieved, if the argon flow is more than 3NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased;
when the preheating temperature of argon is 700-800 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 4.5-5.5, 5-7 and 3-4 NL/min. If the argon flow of the stopper rod is less than 4.5NL/min, the effect of removing fine particles cannot be achieved, and if the argon flow of the stopper rod is more than 5.5NL/min, a plurality of bubbles can appear, and the fluctuation of the liquid level is increased; if the argon flow of the water feeding port of the tundish is less than 5NL/min, the effect of removing fine particles cannot be achieved, if the argon flow is more than 7NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased; if the argon flow of a submerged nozzle of the crystallizer is less than 3NL/min, the effect of removing fine particles cannot be achieved, if the argon flow is more than 4NL/min, a plurality of bubbles can appear, and liquid level fluctuation is increased;
preferably, the preheating temperature of the argon gas is detected every 5-10 minutes, and the flow of the argon gas is dynamically controlled according to the measured temperature of the argon gas. The reason for detecting once every 5-10 minutes is as follows: less than 5 minutes of fluctuation of the argon flow rate increases the cost too frequently, and more than 10 minutes of fluctuation of the argon flow rate is large, so that the argon flow rate is difficult to be accurately and dynamically monitored.
From the above, it can be seen that the method for blowing argon in slab continuous casting provided by the invention is based on the mutual cooperation of the steps 1-2 in the invention: (1) after the argon is preheated, the higher the temperature is, the smaller the volume expansion is after entering molten steel, and the smaller the influence on the liquid level fluctuation of the crystallizer is; (2) then the flow of argon gas is dynamically controlled according to the temperature after the argon gas is preheated, the higher the temperature is, the larger the flow of argon gas is blown, which is beneficial to removing fine impurities, preventing the occurrence of water gap blockage, and simultaneously, the influence on liquid level fluctuation can be obviously reduced when the liquid level surface layer of the crystallizer overflows. By adopting the method, the area ratio of the inclusions in the casting blank is reduced by 5-10 ppm, and the proportion of the liquid level fluctuation of the crystallizer within +/-3 is improved by 5-15%.
On the other hand, as shown in fig. 1-2, a slab continuous casting argon blowing device provided in an embodiment of the present invention is provided, where a stopper hole 4, a temperature measurement charging hole 5, and a tundish upper water hole 6 are provided on a tundish cover body 3, and this embodiment provides a slab continuous casting argon blowing device, including:
the heating pipeline 2 is used for preheating argon; the heating pipeline 2 is pre-buried in the tundish cover body 3, and the heating pipeline 2 is provided with an outlet 2-2 and an inlet 2-1 for connecting an argon supply pipeline;
the stopper rod argon blowing branch pipe 7 is used for conveying argon to the stopper rod; one end of the stopper rod argon blowing branch pipe 7 is communicated with the outlet 2-2 of the heating pipeline, and the end head of the other end of the stopper rod argon blowing branch pipe is downwards aligned to the inside of the stopper rod 4;
the tundish upper nozzle argon blowing branch pipe 8 is used for conveying argon to the tundish; one end of the tundish upper nozzle argon blowing branch pipe 8 is communicated with the outlet 2-2 of the heating pipeline, and the end 8-1 of the other end is downwards aligned to the tundish upper nozzle 6.
An argon blowing branch pipe 9 of a submerged nozzle of the crystallizer is used for conveying argon to the crystallizer; one end of the argon blowing branch pipe 9 of the submerged nozzle of the crystallizer is communicated with the outlet 2-2 of the heating pipeline, and the end head of the other end of the argon blowing branch pipe is downwards aligned with the submerged nozzle of the crystallizer (as known by the skilled person, the crystallizer is positioned below the tundish when in use, and is not shown in the figure of the crystallizer).
In the device for blowing argon in slab continuous casting provided by the embodiment of the invention, before the pouring of the tundish, an operator connects the argon gas supply pipeline 1 with the inlet 2-1 of the heating pipeline 2 through the quick connector, argon gas reaches each area in the tundish through the heating pipeline, the argon gas in the pipeline is heated by using radiant heat in the baking process of the tundish and the pouring process of molten steel,
because of a plurality of argon branch pipes in one side of the tundish cover body, the plurality of argon branch pipes comprise a stopper rod argon blowing branch pipe 7 and a tundish upper nozzle argon blowing branch pipe 8; before the molten steel is cast, the gas supply valves of the stopper rod argon blowing branch pipe 7, the tundish upper nozzle argon blowing branch pipe 8 and the crystallizer submerged nozzle argon blowing branch pipe 9 are opened, meanwhile, the argon gas temperature at the outlets of the three branch pipes is measured, and the argon gas flow blown in by the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle respectively is dynamically adjusted according to the measured temperature. Therefore, air in the tundish is exhausted through argon, inert gas protective atmosphere is formed in the tundish, then pouring processes such as molten steel injection and the like are carried out, and oxygen and nitrogen increasing of the molten steel caused by contact of the molten steel and the air can be avoided. Meanwhile, the argon blowing state can be kept all the time in the whole production process, so that the upper surface of the molten steel is always in an inert protective atmosphere, air is isolated, and the air is prevented from being slowly diffused like steel. And the higher the temperature after the argon gas is preheated, the smaller the volume expansion after the argon gas enters molten steel, the smaller the influence on the liquid level fluctuation of the crystallizer, the higher the temperature is, the larger the argon blowing flow is, the removal of fine inclusions is facilitated, the occurrence of water gap blockage is prevented, and meanwhile, the influence on the liquid level fluctuation can be obviously reduced when the liquid level surface layer of the crystallizer overflows.
The method for blowing argon in slab continuous casting according to the present application will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
The test casting steel is high-grade pipeline steel SDC06, the main components are shown in Table 1, the continuous casting machine is a double-flow slab continuous casting machine, the castable section is 230mm multiplied by (900-. The simulated casting is carried out before the casting, the section of the slab is 230mm multiplied by 1100mm, the pulling speed is 1.3m/min, and the tundish tolerance is 60 t.
TABLE 1 main component/% of test steel
| Finished component C | Finished product ingredient Si | Finished component Mn | Finished component P | Finished product ingredient S | Finished product ingredient Alt |
| 0.0014 | 0.01 | 0.14 | 0.012 | 0.007 | 0.029 |
Three argon gas supply pipelines before pouring are connected to a heating pipeline on the inner surface of the tundish cover through a gas inlet quick-change connector, and argon in the pipelines is heated by utilizing radiant heat in the baking process of the tundish and the pouring process of molten steel.
Before the molten steel is poured, the gas supply valves of the stopper rod argon blowing branch pipe, the tundish upper nozzle argon blowing branch pipe and the crystallizer submerged nozzle argon blowing branch pipe are opened, meanwhile, the argon temperature at the outlet is 650 ℃, and through a secondary PLC program, the argon flow rates respectively blown by the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle are automatically adjusted to be 4.5, 4 and 2.5 NL/min.
After the casting is started for 25min, the temperature of argon at the outlet is raised to 732 ℃, and the flow rates of argon respectively blown by the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle are automatically adjusted to 5.5, 6 and 3.5NL/min through a secondary PLC program.
During the rest pouring time, the temperature of argon is between 700 ℃ and 800 ℃, and the flow of argon is kept until the pouring of 6 furnaces is finished.
After the pouring is finished, the fluctuation of the liquid level of the crystallizer in the pouring process is counted, the ratio within +/-3 of the fluctuation reaches 97 percent, and the fluctuation is improved by 7 percent compared with the traditional process of the following comparative example 1. The area ratio of the inclusions in the surface layer of the narrow surface of the casting blank within 5mm is analyzed, and is 41ppm, which is 6ppm lower than that of the traditional process. Meanwhile, the cold rolling degradation rate is reduced by 15 percent compared with the traditional process of the comparative example 1.
Example 2
The test casting steel is high-grade pipeline steel SDC05, the main components are shown in Table 1, the continuous casting machine is a double-flow slab continuous casting machine, the castable section is 230mm multiplied by (900-. The simulated casting is carried out before the casting, the section of the slab is 230mm multiplied by 1600mm, the pulling speed is 1.2m/min, and the tundish tolerance is 60 t.
TABLE 2 main component/% of test steel
| Finished component C | Finished product ingredient Si | Finished component Mn | Finished component P | Finished product ingredient S | Finished product ingredient Alt |
| 0.0019 | 0.01 | 0.14 | 0.012 | 0.008 | 0.031 |
Three argon gas supply pipelines before pouring are connected to a heating pipeline on the inner surface of the tundish cover through a gas inlet quick-change connector, and argon in the pipelines is heated by utilizing radiant heat in the baking process of the tundish and the pouring process of molten steel.
Before the molten steel is poured, the gas supply valves of the stopper rod argon blowing branch pipe, the tundish upper nozzle argon blowing branch pipe and the crystallizer submerged nozzle argon blowing branch pipe are opened, meanwhile, the argon temperature at the outlet is 610 ℃, and through a secondary PLC program, the argon flow rates respectively blown by the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle are automatically adjusted to be 4.5, 4 and 2.5 NL/min.
After the casting is started for 50min, the temperature of argon at the outlet is raised to 764 ℃, and the flow rates of argon respectively blown into the stopper, the tundish water feeding port and the crystallizer submerged nozzle are automatically adjusted to 5.5, 6 and 3.5NL/min through a secondary PLC program.
After the casting is started for 130min, the temperature of argon at the outlet is reduced to 681 ℃, and the flow of argon respectively blown into the stopper, the tundish upper nozzle and the crystallizer submerged nozzle is automatically adjusted to 4.5, 4 and 2.5NL/min through a secondary PLC program.
During the rest pouring time, the temperature of argon is between 500 ℃ and 700 ℃, and the flow of argon is kept until the pouring of 7 furnaces is finished.
After the pouring is finished, the fluctuation of the liquid level of the crystallizer in the pouring process is counted, the ratio of the fluctuation within +/-3 reaches 96%, and the fluctuation is improved by 6% compared with the traditional process. The area ratio of the inclusions in 5mm of the surface layer of the narrow side of the cast slab was analyzed to be 39ppm, which is 8ppm lower than that of the conventional process of comparative example 1 described below. Meanwhile, compared with the traditional process of the comparative example 1, the cold rolling degradation rate is reduced by 13%.
Comparative example 1
The comparative example adopts the traditional process, namely preheating of argon is not carried out, the temperature of the argon is not measured, the flow rates of the argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle are not dynamically controlled according to the temperature of the argon, and the flow rates of the argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle are respectively 9-14L/min, 5-10L/min and 2-4L/min.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. A method for blowing argon in slab continuous casting, which is characterized by comprising the following steps:
preheating argon to 300-800 ℃;
in the slab continuous casting process, blowing the preheated argon into a stopper rod, a tundish water feeding port and a crystallizer submerged nozzle respectively, and monitoring the temperature of the preheated argon;
according to the monitoring result, argon flow of the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is respectively adjusted; the flow rate of the argon gas is 1 to 7 NL/min.
2. A method of blowing argon for slab casting according to claim 1, wherein said preheating argon gas comprises:
the heating pipeline is embedded in the tundish cover body, an inlet of the heating pipeline is connected into the argon gas supply pipeline through a quick-change connector, and argon gas in the heating pipeline is heated by utilizing radiant heat in the tundish baking and molten steel pouring processes.
3. The method for blowing argon for slab continuous casting according to claim 1, wherein the dynamically controlling the flow rate of argon gas according to the measured temperature of argon gas is specifically:
when the preheating temperature of argon is 300-500 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 1-3, 1-3 and 1-2 NL/min;
when the preheating temperature of argon is 500-700 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 3-4.5, 3-5 and 2-3 NL/min;
when the preheating temperature of argon is 700-800 ℃, the flow of argon respectively blown into the stopper rod, the tundish upper nozzle and the crystallizer submerged nozzle is 4.5-5.5, 5-7 and 3-4 NL/min.
4. A method of blowing argon for slab continuous casting according to claim 1, wherein the preheating temperature of argon is detected every 5 to 10 minutes, and the flow of argon is dynamically controlled according to the measured temperature of argon.
5. A slab continuous casting argon blowing method according to claim 1, characterized in that the method is suitable for a tundish of 40-80 tons.
6. A slab continuous casting argon blowing method according to claim 1, characterized in that the method is suitable for all steel grades and continuous casting machines with the continuous casting machine pulling speed of 0.8-1.7 m/min.
7. A device for blowing argon in slab continuous casting is characterized by comprising the following components:
the heating pipeline is used for preheating argon;
the stopper rod argon blowing branch pipe is used for conveying argon to the stopper rod;
the argon blowing branch pipe is used for conveying argon to the tundish;
the submerged nozzle argon blowing branch pipe of the crystallizer is used for conveying argon to the crystallizer;
the heating pipeline is embedded in the tundish cover body and is provided with an outlet and an inlet for connecting an argon supply pipeline;
one end of the stopper rod argon blowing branch pipe is communicated with an outlet of the heating pipeline, and the other end of the stopper rod argon blowing branch pipe is communicated with the inside of the stopper rod;
one end of the tundish upper nozzle argon blowing branch pipe is communicated with an outlet of the heating pipeline, and the other end of the tundish upper nozzle argon blowing branch pipe is communicated with the tundish upper nozzle;
one end of the submerged nozzle argon blowing branch pipe of the crystallizer is communicated with an outlet of the heating pipeline, and the other end of the submerged nozzle argon blowing branch pipe of the crystallizer is communicated with the submerged nozzle of the crystallizer.
8. The apparatus for slab casting argon blowing according to claim 7,
the end of one end of the argon blowing branch pipe of the stopper rod, which is communicated with the stopper rod, is downward and is aligned with the inside of the stopper rod;
the end of one end of the tundish upper nozzle argon blowing branch pipe communicated with the tundish upper nozzle is downwards aligned with the tundish upper nozzle;
the end of one end of the submerged nozzle argon blowing branch pipe of the crystallizer, which is communicated with the submerged nozzle of the crystallizer, is downwards aligned with the upper nozzle of the tundish.
9. The apparatus for blowing argon for slab casting according to claim 7, wherein an inlet of the heating line is connected to an argon gas supply line through a quick change coupler.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113798483A (en) * | 2021-08-30 | 2021-12-17 | 山东钢铁集团日照有限公司 | Control method for improving argon blowing effect of long pouring times of stopper rod |
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