WO2022022277A1 - Lf refining ladle microporous ceramic rod air-permeable upper nozzle well block, and argon blowing control method therefor - Google Patents

Abstract

An LF refining ladle microporous ceramic rod air-permeable upper nozzle well block, comprising an iron ring (7) and microporous ceramic rods (2). The diameter d of the microporous ceramic rod is 35-45 mm; the height h of the ceramic rod is 140-180 mm; air-permeable holes are arranged in the ceramic rod along the axial direction of the ceramic rod and evenly distributed on the cross section of the ceramic rod; 60-120 air-permeable holes are provided; the inner diameter of the air-permeable hole is 0.075-0.1 mm; the air-permeable holes longitudinally pass through the upper end surfaces and the lower end surfaces of the microporous ceramic rods. An argon blowing control device, provided with an argon pipeline system and an electrical control system, and having a manual air-permeable upper nozzle well block blowing-through or automatic soft blowing mode selection function. An argon blowing control method, before an automatic soft blowing mode is selected, a manual bypass in the argon pipeline system being used to blow through the air-permeable upper nozzle well block, so as to achieve precise control to argon blowing flow and prolong the service life of the ladle air-permeable upper nozzle well block.

Description

A kind of LF refining ladle microporous ceramic rod permeable upper nozzle block and argon blowing control method technical field

The invention relates to an LF refining ladle microporous ceramic rod permeable upper nozzle block and a control method for argon blowing, belonging to the technical field of steelmaking technology in iron and steel metallurgy.

Background technique

Argon blowing at the bottom of LF refining ladle is a simple and efficient out-of-furnace refining technology. It is generally divided into two stages of mixing and mixing with large flow argon blowing in the early stage and soft blowing with small flow in the later stage to remove inclusions. At present, the domestic LF refining ladle of more than 100 tons generally uses two bottom-blown ventilation bricks. The processing time of high-quality steel is generally more than 40 minutes, of which soft blowing is 8-12 minutes. At present, there are the following problems or deficiencies in production practice: (1 ) Insufficient soft blowing time, which affects the removal effect of inclusions; (2) Excessive LF refining time causes mismatch of furnace and machine, which becomes a restrictive link for increasing production and efficiency; (3) The soft blowing flow control is not accurate, and the flow rate is too high. Small influence on the effect of soft blowing to remove inclusions, excessive flow will cause problems such as exposed molten steel surface, slag entrainment and large molten steel temperature drop.

Chinese patent document CN104028739A (Patent No.: 201410274221.8) discloses a ladle breathable upper nozzle block and a method for controlling slag under the ladle, including a nozzle block body, a breathable ceramic rod, an air chamber box, an air intake pipe, and a nozzle block. The middle part of the brick body is provided with a flow steel hole and an upper nozzle installation hole from top to bottom, and a circular evenly arranged microporous ceramic rod and an annular air chamber box are arranged in the upper nozzle seat brick body, and the bottom of the air chamber box is connected. There is an air inlet pipe. When the molten steel in the ladle is at a low level, argon gas is blown from the air inlet pipe to control the eddy current slag entrainment problem at the upper nozzle of the ladle. This patent is mainly aimed at suppressing the problem of slag rolling at the ladle nozzle at the end of ladle pouring. The patent has the following shortcomings: the diameter of a single gas-permeable ceramic rod is small, the gas-permeable surface is small, the distribution density of pores is small, the number of argon bubbles formed by blowing argon is small, which is not conducive to the metallurgical effect of removing inclusions, and the height of a single gas-permeable ceramic rod is large. It is difficult, and argon is only blown in the later stage of ladle pouring, and there is no metallurgical function to remove inclusions by blowing argon at a small flow rate. At the same time, the argon blowing flow rate is not correspondingly reduced according to the reduction of the molten steel level in the ladle, which is prone to exposed molten steel surface and slag. And problems such as large molten steel temperature drop.

Chinese patent document CN109719290A (application number: 2019101296742.1) discloses a ladle annular seam type breathable upper nozzle block and an argon blowing metallurgical method, including a ladle upper nozzle block body, a circular seam, an air chamber box, an air intake pipe, a ladle upper nozzle block The middle part of the brick body of the nozzle seat is provided with a flow steel hole, a connection hole and a nozzle installation hole that penetrate up and down. During the pouring process of the continuous casting ladle, argon gas is blown into the whole process, and the argon gas is automatically adjusted according to the change of the net weight of the molten steel in the ladle. Flow, argon gas passes through the annular gap to form tiny argon bubbles, and most of the argon bubbles move upward, forming a ring-shaped air curtain barrier around the ladle upper nozzle, and air washes the molten steel that is about to enter the ladle upper nozzle. It forms a stable and continuous annular airflow, suppresses the nodules at the upper nozzle, and effectively suppresses the slag under the ladle caused by the confluence vortex and the drainage sinkhole in the later stage of ladle pouring. The patent has the following shortcomings: the ventilation channel is a circular seam, the argon bubbles formed by argon blowing are large and the number is small, which affects the metallurgical effect of argon blowing. According to the different control requirements for inclusions in the steel, different argon blowing control methods are selected and argon blowing throughout the process. This results in a large drop in molten steel temperature, which affects popularization and application, and the ladle ventilation nozzle block is not manually blown before argon is automatically blown. The ventilation channel is easily blocked by infiltrating molten steel and steel slag, resulting in the flow rate of the gas permeable nozzle block in the early stage of argon blowing. Small or the bottom blowing cannot be opened, which seriously affects the metallurgical effect of argon blowing.

Chinese patent document CN106041044A (patent number: 201610634268.X) discloses a continuous casting tundish air-permeable ceramic pipe upper nozzle block, including a nozzle block body, a ceramic tube, an air chamber, an air intake pipe, and a nozzle block body There are a plurality of ceramic tubes uniformly arranged in a circular ring and a circular air chamber. The air chamber is provided with a plurality of sockets that are uniformly arranged in a circular ring. The top of the ceramic tube protrudes from the upper surface of the nozzle seat brick body. , the lower end of the ceramic tube is fixed in the socket on the air chamber and communicated with the air chamber. The side of the air chamber is connected with an air inlet pipe, which is connected with the external argon gas source through the connecting metal pipe fitting, and the argon gas is blown upward to form a ring shape The air curtain barrier is used to wash the molten steel entering the water inlet, and a certain number of argon bubbles enter the water inlet with the steel flow, forming a stable and continuous annular airflow, which not only suppresses the problem of nodules at the nozzle, but also solves the problem of It solves the technical problem that the protective argon bubbles enter the steel and cause the subcutaneous bubbles of the casting billet. The patent has the following shortcomings: the inner diameter of the air holes in the ceramic tube is large, the number of air holes in the ceramic tube is small, the argon bubbles formed by argon blowing are too large and the number is small, which affects the metallurgical effect of argon blowing, and the air holes are easily blocked by steel permeation , not easy to blow through.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention provides an LF refining ladle microporous ceramic rod permeable upper nozzle block and a method for controlling argon blowing.

The technical scheme involved in the invention solves the problems of the ceramic rod described in the Chinese patent document CN104028739A, the poor molding quality due to the large height, the difficult positioning of the ceramic rod during the pouring process of the ladle nozzle block body, and the easy blockage. Precise control improves the oxygen-free purging rate and service life of the ladle breathable upper nozzle block.

Oxygen-free purging rate of the ladle breathable upper nozzle block refers to the measurement of the air permeability of the ladle air permeable nozzle block after the ladle is poured and off the line. , when the air permeability reaches the process requirements, it is exempted from the oxygen-burning purging treatment. The oxygen-free purging rate = the number of furnaces exempted from the oxygen-burning purging treatment ÷ the total number of furnaces × 100%.

Technical solution of the present invention

An LF refined ladle microporous ceramic rod breathable upper nozzle block brick, comprising a ladle nozzle block body (1), a microporous ceramic rod (2), an air chamber box (3), an air intake pipe (4), a flow steel hole ( 5), the upper nozzle mounting hole (6); it is characterized in that:

The flow steel hole (5) and the upper nozzle installation hole (6) are connected up and down, and are installed in the middle of the ladle nozzle seat brick body (1);

The air chamber box (3) is embedded in the surface layer of the upper part of the ladle nozzle block body (1); the air chamber box (3) is provided with a plurality of sockets (8), and the sockets (8) are used for fixing the microporous ceramic rod ( 2);

There are a plurality of microporous ceramic rods (2), which are uniformly arranged in the ladle nozzle block body (1) in a ring shape, and the top of each microporous ceramic rod (2) protrudes out of the ladle nozzle block body (1). On the upper surface, the bottom end of each microporous ceramic rod (2) extends into the air chamber box (3), and the shape, number and position of the sockets (8) correspond to those of the microporous ceramic rod (2);

One end of the air inlet pipe (4) is connected to the side part of the air chamber box (3), and the other end extends from the side part of the ladle nozzle block body (1).

Preferably, the microporous ceramic rod (2) is cylindrical, the diameter d is 35-45 mm, and the height h of the ceramic rod is 140-180 mm.

Preferably in the present invention, the microporous ceramic rod (2) is provided with ventilation holes along the axial direction of the microporous ceramic rod, which are evenly distributed on the cross section of the microporous ceramic rod, and the number of ventilation holes is 60-60 There are 120 ventilation holes, the inner diameter of which is 0.075-0.1 mm, and the ventilation holes longitudinally penetrate the upper and lower end surfaces of the microporous ceramic rod.

Preferably, the microporous ceramic rod (2) is extruded and fired at high temperature, and the material is zirconia toughened corundum or zirconia toughened corundum mullite.

Preferably, the number of the microporous ceramic rods (2) is 6-10, which are evenly arranged in a ring shape, and the diameter of the ring formed by the microporous ceramic rods (2) is 300-320 mm. (2) The center is the benchmark.

Preferably, the height m of the upper end of the microporous ceramic rod (2) protruding from the upper surface of the ladle nozzle block body (1) is 5-10 mm, and the bottom end of the microporous ceramic rod (2) is 5-10 mm. The height n extending into the air chamber box is 5-10 mm.

Preferably, the microporous ceramic rod air-permeable upper nozzle block includes an iron ring (7), and the iron ring (7) is embedded in the surface layer of the lower part of the ladle nozzle block body (1).

The iron ring (7) is embedded in the surface layer of the lower part of the ladle nozzle block body (1), which effectively suppresses the crack problem caused by the thermal stress of the ladle nozzle block body.

Preferably in the present invention, the iron ring (7) as a whole is a circular ring, the height L is 40-50 mm, the distance a between the lower end of the iron ring and the lower end of the ladle nozzle block body (1) is 50-60 mm, and the iron ring ( 7) The depth z in the surface layer of the brick body (1) buried in the ladle nozzle seat is 10-20mm.

Preferably in the present invention, the iron ring (7) is welded with a 1 mm thick iron sheet, the overlapping length of the joint is 40-50 mm, and full welding is adopted.

Preferably, the air chamber box (3) is in the shape of a circular ring as a whole, the air chamber box is made of a metal box with a thickness of 1.5-2.0 mm steel plate, the longitudinal section of the metal box is a rectangle, and the width x of the rectangle is 50-60mm, height y is 30-40mm, its cross section is a ring, and a plurality of sockets (8) are evenly distributed on the ring.

Preferably in the present invention, the ladle nozzle block body (1) is cast and formed from chrome corundum castables, with a bulk density of ≥3.0g/cm ³ , a high-temperature flexural strength of ≥12Mpa, a high-temperature compressive strength of ≥80Mpa, and AL ₂ O ₃ content ≥ 92%, Cr ₂ O ₃ content ≥ 3%.

Preferably in the present invention, the longitudinal centerlines of the flow steel hole (5) and the upper nozzle installation hole (6) are on a straight line with the longitudinal centerline of the ladle nozzle block body (1), and the flow steel hole ( 5) The upper part is truncated, the diameter d1 of the upper port of the truncated truncated table is 190-210mm, the diameter of the lower port d2 is 140-160mm, the height c of the truncated table is 55-80mm, and the lower part of the flow steel hole (5) is a cylindrical channel , the diameter of the lower cylindrical channel is the same as the diameter of the lower port of the upper circular table, and the height b of the cylinder is 250-270 mm.

Preferably, in the present invention, the upper part of the upper nozzle installation hole (6) is truncated, and the fitting size of the upper nozzle installation hole is designed according to the external dimension of the nozzle.

Preferably, the ladle nozzle block body (1) has a cylindrical shape, the cylindrical outer diameter D is 380-400 mm, and the cylindrical height H is 470-490 mm.

The air inlet pipe (4) of the present invention is made of a heat-resistant stainless steel round pipe, the end of which is provided with a connecting thread, and the size is M16×1.5.

In the LF refining ladle microporous ceramic rod air permeable upper nozzle block, the microporous ceramic rod (2) is provided with ventilation holes along the axial direction of the microporous ceramic rod, and in the transverse direction of the microporous ceramic rod Evenly distributed on the cross section, the number of ventilation holes is 60-120, the inner diameter of the ventilation holes is 0.075-0.1mm, the height h of the ceramic rod is 140-180mm, and the iron ring is set to be buried in the surface layer of the lower part of the brick body of the ladle nozzle. The shape of the ladle nozzle block brick body is cylindrical and other designs. It is an essential technological innovation for the problems existing in the existing patented technology. It is obtained through a large number of research experiments and production experiments. On the basis of physical simulation research, by reducing the inner diameter of the air holes in the ceramic rod and increasing the number of air holes in the ceramic rod, the formation of argon blowing is more than the ceramic tube described in Chinese patent document CN106041044B (patent number: 201610634268.X). More and smaller argon bubbles improve the ability of argon bubbles to capture and remove inclusions, and enhance the function of suppressing the slag under the ladle caused by the confluence vortex and drainage sinkholes at the end of the pouring stage. It is not easy to infiltrate steel in the vent hole, and it is easy to blow through; the second is to reduce the height of the microporous ceramic rod as much as possible according to the erosion residual height of the LF refining ladle microporous ceramic rod permeable upper nozzle block, so as to solve the problem described in Chinese patent document CN104028739B The poor molding quality of the ceramic rods due to the high height and the difficult positioning of the ceramic rods during the pouring process of the ladle nozzle block body; third, through a large number of production and application tests, the iron ring is set to be buried in the surface layer of the lower part of the ladle nozzle block body. , effectively suppressing the crack problem caused by the thermal stress of the ladle nozzle block body, and prolonging the service life of the ladle microporous ceramic rod breathable nozzle block brick.

The invention also provides an argon blowing control device for LF refining ladle ventilation upper nozzle block, which is characterized in that a set of argon gas pipeline system and electrical control system is provided, which has manual blowing ventilation upper nozzle block and automatic soft Blowing mode selection function, and the introduction of the molten steel weighing signal in the ladle, according to the change of the net weight of the molten steel in the ladle, the argon gas flow is adjusted synchronously, and the precise control of the argon blowing flow of the permeable upper nozzle block is realized.

Preferably in the present invention, the argon gas pipeline system is divided into a main gas source circuit, an automatic branch circuit, a manual bypass circuit and a release branch circuit, and the main gas source circuit, the automatic branch circuit and the manual bypass circuit are communicated through the gas bus bar 18; The main gas source circuit includes in turn the first ball valve 9a, the first pressure gauge 10a, the first gas filter 11a1, the second gas filter 11a2, the pressure regulator 12, and the first pressure sensor 15a in the main gas source circuit; the automatic branch circuit It includes the automatic branch second ball valve 9b1, the first solenoid valve 13b, the metallurgical special mass flow controller 14, the second pressure sensor 15b, the second pressure gauge 10b, and the automatic branch third ball valve 9b2 in sequence; the manual bypass sequentially includes manual bypass. The bypass fourth ball valve 9c and the manual regulating valve 16; the manual bypass is connected in parallel with the second ball valve 9b1 of the automatic branch, the second solenoid valve 13b, and the metallurgical special mass flow controller 14, which is used for manual operation after the automatic branch fails. Operate the application. The argon gas pipeline system involved in the present invention is also used for high pressure blow-through before automatic argon blowing of the upper nozzle block of the LF refining ladle. The valve 13c and the exhaust throttle valve 17 are used to connect the intake metal hose of the ventilation upper nozzle seat brick to exhaust and release the pressure when it needs to be pulled and inserted.

Preferably in the present invention, the electrical control system adopts the existing technology, including network switch, argon blowing control system PLC, touch screen, continuous casting basic automation system, argon blowing control system PLC, touch screen are arranged in the control box, argon blowing control system The system PLC, touch screen, and continuous casting basic automation system are all connected to the network switch through Ethernet communication. The molten steel weighing system in the ladle collects and sends the molten steel weight in the ladle to the continuous casting basic automation system, and then communicates with the network through Ethernet communication and network switch. Upload to the PLC of the argon blowing control system, as shown in Figure 5. The continuous casting basic automation system receives the molten steel weight data in the ladle of the molten steel weighing system, and uploads the data to the argon blowing control system PLC through Ethernet communication and network switch. The argon blowing control system PLC receives the molten steel weight data in the ladle, and executes the argon flow automatic control instruction of the argon blowing control system PLC, and automatically adjusts the argon flow in the gas outlet pipeline according to the change of the molten steel weight in the ladle. Preferably, in the present invention, the gas permeable upper nozzle block in the above-mentioned argon blowing control device is the microporous ceramic rod gas permeable nozzle block in the present invention.

The present invention also provides a kind of argon blowing control method, is characterized in that, comprises the following steps:

The first step is to apply the argon blowing control device of the present invention for the first time, and measure the initial flow value of the soft blowing of the upper nozzle seat brick of the ladle full of air permeable;

In the second step, after the ladle is in the pouring position on the continuous casting ladle turntable, a metal hose is used to connect the air inlet pipe (4) of the gas permeable upper nozzle block with the gas source outlet of the argon gas control device, and the ladle is transferred to the pouring position to open. After pouring and flowing down, immediately use the manual bypass in the argon gas pipeline system to blow through the above-mentioned breathable upper nozzle block: by adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, gradually increase the pressure, Increase by 1-10mbar each time until the above-mentioned ventilating upper nozzle block is blown through.

In the third step, according to the different control requirements for inclusions in the steel, in the second step, after the permeable upper nozzle block is blown through, different automatic soft blowing modes are immediately activated. The change of the net weight of molten steel, linearly adjust the argon flow, the set value of argon flow during the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial flow value of the soft blowing when the ladle is full in step 1 + (2 ~5) NL/min, when the molten steel casting amount reaches 30-100% of the total molten steel in the ladle, keep the flow rate at 2-5NL/min and blow argon. Argon purge was stopped.

Preferably according to the present invention, in step 3, different automatic soft blowing modes are selected according to different control requirements for inclusions in the steel:

(1) For low-end steel grades without inclusion control requirements, use automatic soft blowing mode A: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow Argon, according to the change of the net weight of molten steel in the ladle, adjust the argon flow rate linearly, the set value of argon flow rate during the molten steel pouring = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial soft blowing when the ladle is full in step 1 The flow value is +(2~5)NL/min. When the molten steel casting amount reaches 30~40% of the total molten steel in the ladle, keep the flow rate at 2~5NL/min and blow argon. Stop blowing argon after the stage is ready for pouring;

(2) For mid-end steel grades with inclusion control requirements, use soft blowing mode B: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow argon. , according to the change of the net weight of molten steel in the ladle, adjust the argon flow linearly, the set value of argon flow during the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial flow of the soft blowing when the ladle is full in step 2 value +(2~5)NL/min, when the molten steel casting amount reaches 50~60% of the total molten steel in the ladle, keep the flow rate at 2~5NL/min and blow argon, when the ladle is poured, turn it back to the continuous casting turntable Stop blowing argon after pouring;

(3) For high-end steel grades with strict inclusion control, soft blowing mode C is selected: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow argon. The change of the net weight of molten steel in the ladle, linearly adjust the argon flow, and adjust it according to the following formula:

Argon flow setting value in molten steel pouring process = net weight of remaining molten steel in the ladle ÷ net weight of molten steel when the ladle is full × initial flow value of soft blowing when the ladle is full in step 2 + (2 to 5) NL/min,

When the ladle is under slag or the slag detection system alarms, keep the flow rate at 2~5NL/min and blow argon.

Preferably in the present invention, in step 1, the initial flow value of the soft blowing of the upper nozzle block of the ladle is fully blown: when the ladle is fully blown softly in the later stage of LF refining in the prior art, the argon gas for blowing the air-permeable brick at the bottom of the original ladle is turned off. , connect the argon gas of the permeable upper nozzle block, adjust the argon gas flow to gradually increase, observe the slight fluctuation of the molten steel level in the ladle, the argon blowing flow value when the molten steel surface is not exposed is the initial flow value of the ladle full ladle soft blowing .

Preferably, in the present invention, the gas permeable upper nozzle block in the above-mentioned argon blowing control method is the microporous ceramic rod gas permeable nozzle block in the present invention.

The net weight of molten steel when the ladle is full comes from the molten steel weighing system in the ladle set on the continuous casting turntable. The total weight of the net weight of the molten steel minus the calibrated tare weight of the ladle is the net weight of the molten steel when the ladle is full, and the tare weight of the ladle refers to the weight of the ladle when the ladle is empty.

The net weight of the remaining molten steel in the ladle comes from the molten steel weighing system in the ladle set on the continuous casting turntable, which means that during the pouring process of the ladle, the system automatically subtracts the calibrated weight from the total weight of the tare weight of the ladle and the net weight of the remaining molten steel in the ladle. The tare weight of the ladle is the net weight of the remaining molten steel in the ladle, and the tare weight of the ladle refers to the weight of the ladle when it is empty.

The beneficial effects of the present invention are:

1. The diameter d of the microporous ceramic rod in the air-permeable upper nozzle block of the ladle microporous ceramic rod involved in the present invention is 35-45 mm, and a ventilation hole is arranged in the microporous ceramic rod along the axial direction of the microporous ceramic rod. The microporous ceramic rod is evenly distributed on the cross section, the number of ventilation holes is 60-120, and the inner diameter of the ventilation holes is 0.075-0.1mm. The inner diameter of the air holes in the ceramic rod, increasing the number of air holes in the ceramic rod, blowing argon to form more and smaller argon bubbles than the ceramic tube described in the Chinese patent document CN106041044B (patent number: 201610634268.X), which improves the The ability of argon bubbles to capture and remove inclusions enhances the function of suppressing the slag under the ladle caused by the confluence vortex and the drainage sink at the end of the pouring stage, and the reduction of the inner diameter of the air hole makes the air hole difficult to infiltrate steel and easy to blow through. , the invention is applied to the double-flow slab continuous casting machine to produce the ultra-low carbon aluminum killed steel DC04, the automatic soft blowing mode C is selected, the weight of the electrolytic inclusions of the continuous casting slab sample is reduced by more than 20% year-on-year, and the molten steel pouring allowance of the ladle is year-on-year. At the same time, according to the erosion residual height of the breathable upper nozzle block of the LF refining ladle microporous ceramic rod, the height h of the ceramic rod is designed to be 140-180 mm, which reduces the height of the microporous ceramic rod and solves the problem. The problem of the ceramic rod described in the prior art Chinese patent CN104028739B is solved due to the high height in practical application, which leads to the poor molding quality of the ceramic rod and the difficult positioning of the ceramic rod during the pouring process of the ladle nozzle seat brick body.

2. The LF refining ladle microporous ceramic rod permeable upper nozzle block and the argon blowing control method involved in the present invention, through the actual ladle full ladle soft blowing initial flow value, ladle pouring process argon flow setting value = remaining in the ladle Net weight of molten steel ÷ Net weight of molten steel when the ladle is full × initial flow value of soft blowing when the ladle is full + (2～5) NL/min, and according to the different control requirements of inclusions in the steel, different soft blowing modes are selected to effectively solve the problem. Comparative example CN104028739B (Patent No.: 201410274221.8) The flow rate of argon blowing was not reduced according to the reduction of the molten steel level in the ladle, which caused problems such as exposed molten steel surface, slag entrainment and large temperature drop of molten steel, and the average temperature drop of molten steel in the ladle The year-on-year decrease is more than 0.1℃/min.

3. The shape of the brick body of the ladle nozzle seat of the present invention is designed from a traditional square to a cylindrical shape, and the iron ring is embedded in the surface layer of the lower part of the brick body of the ladle nozzle seat, which effectively suppresses the thermal stress of the brick body of the ladle nozzle seat. Compared with the comparative example CN104028739A (patent number: 201410274221.8), the average service life is increased by more than 4 heats compared with the same period of last year.

4. The ladle microporous ceramic rod air permeable nozzle block and the argon blowing control method thereof involved in the present invention are the same as the ladle ring seam type gas permeable nozzle block and the argon blowing metallurgy described in Chinese patent document CN109719290A (application number: 2019101296742.1). Compared with the methods, there are essential differences. First, the ventilation channels are different, the size and number of bubbles formed by argon blowing are different, and the metallurgical effect of argon blowing is different. The gas channel of the present invention is the ventilation hole in the ceramic rod. The axial arrangement of the microporous ceramic rod is uniformly distributed on the cross section of the microporous ceramic rod, the number of ventilation holes is 60 to 120, and the inner diameter of the ventilation holes is 0.075 to 0.1 mm. The diameter of the bubble near the rod is less than 1.8mm, and the inclusion removal rate obtained by the digital model is 54-67%, while the gas channel of CN109719290A (application number: 2019101296742.1) is a ring seam, and the width of the ring seam is 1.3-1.7mm. The bubble diameter of the annular seam measured in the model experiment is less than 2mm, and the inclusion removal rate obtained by the numerical model is 37-48%. Second, the argon blowing control method is different. Before the automatic soft blowing mode is selected in the present invention, the manual bypass in the argon gas pipeline system is used to blow through the permeable upper nozzle block bricks, which realizes one-time blowing through of the permeable upper nozzle block bricks. The flow rate is above 99%, and the flow rate of argon blowing is kept at 2~5NL/min in the later stage of ladle pouring, which avoids molten steel and steel slag from immersing in the ventilation channel of the permeable upper nozzle block, and improves the ladle ventilation. According to the different control requirements of inclusions in the steel, different automatic soft blowing modes are selected. Among them, the automatic soft blowing modes A and B are not argon blowing in the whole process, respectively, when the molten steel casting amount reaches 30-40% of the total molten steel in the ladle , 50-60%, the flow rate is 2-5NL/min to blow argon, and the comparative test results for the production of low-carbon aluminum-killed steel SPHC by the double-flow slab continuous casting machine of a steel plant show that the ladle involved in the present invention is applied. Compared with the argon blowing control method for the permeable upper nozzle block of the ladle related to the application of the comparative example CN109719290A (application number: 2019101296742.1), the average temperature drop of the molten steel in the ladle is reduced by 0.06°C/min year-on-year. The one-time blow-through rate of the permeable upper nozzle block brick is increased by 11% year-on-year, and the non-burning oxygen purging rate of the ladle permeable nozzle block brick is increased by 13% year-on-year. The invention relates to a ladle microporous ceramic rod permeable nozzle. obvious advantages.

Description of drawings

Fig. 1 is the front view of LF refining ladle microporous ceramic rod ventilation upper nozzle block structure in the embodiment of the present invention;

In the figure, 1. Ladle nozzle seat brick body; 2. Microporous ceramic rod; 3. Air chamber box; 4. Air inlet pipe; 5. Flow steel hole; 6. Upper nozzle installation hole;

Fig. 2 is the top view of LF refining ladle microporous ceramic rod breathable upper nozzle seat brick in the embodiment of the present invention;

In the figure, 1. Ladle nozzle block body; 2. Microporous ceramic rod; 3. Air chamber box; 4. Air intake pipe; 7. Iron ring.

3 is a schematic structural diagram of an air chamber box in an embodiment of the present invention;

In the picture, 8. Socket.

4 is a schematic diagram of an argon gas pipeline system in an embodiment of the present invention;

In the figure, 1. The ladle nozzle seat brick body; 4. The air inlet pipe; Four-ball valve 9c); 10. Pressure gauge (including first pressure gauge 10a, second pressure gauge 10b); 11. Gas filter (including first gas filter 11a1, second gas filter 11a2); 12. Pressure regulation 13. Solenoid valve (including automatic main circuit first solenoid valve 13b, manual bypass second solenoid valve 13c); 14. Metallurgical special mass flow controller; 15. Pressure sensor (including gas source main circuit first pressure sensor 15a. The second pressure sensor 15b) of the automatic branch; 16. Manual regulating valve; 17. Exhaust throttle valve; 18. Gas bus.

FIG. 5 is a schematic diagram of an electrical control system in an embodiment of the present invention.

detailed description

The present invention will be further described below with reference to the accompanying drawings and embodiments, but the protection scope is not limited thereto.

Example 1

A LF refined ladle microporous ceramic rod breathable upper nozzle block, as shown in Figures 1-3, includes a ladle nozzle block body 1, a microporous ceramic rod 2, an air chamber box 3, an air intake pipe 4, and an iron ring 7. , the middle part of the ladle nozzle seat brick body is provided with a flow steel hole 5 and an upper nozzle installation hole 6 that penetrate up and down, and the microporous ceramic rods 2 are 10, which are evenly arranged in the ladle nozzle seat brick body 1 in a ring shape, The top of each microporous ceramic rod 2 protrudes from the upper surface of the ladle nozzle block body, and the bottom end of each microporous ceramic rod 2 extends into the air chamber box, which is provided with a plurality of fixed microporous ceramic rods. There are 10 sockets 8 of the rod. The shape, quantity and position of the sockets correspond to the microporous ceramic rods. The side of the air chamber box 3 is connected with an air intake pipe 4. The side part of the mouth seat brick body 1 protrudes, and it is characterized in that the microporous ceramic rod 2 is cylindrical, the diameter d is 35mm, and the height h of the ceramic rod is 140mm.

The microporous ceramic rod 2 is provided with ventilation holes along the axial direction of the microporous ceramic rod, which are evenly distributed on the cross section of the microporous ceramic rod, the number of ventilation holes is 60, and the inner diameter of the ventilation holes is 0.1 mm.

The number of the microporous ceramic rods 2 is 10, which are evenly arranged in a ring shape, and the diameter of the ring ring is 300mm.

The air chamber box 3 is circular as a whole, and the air chamber box is a metal box made of 2.0mm steel plate. The cross section of the metal box is a rectangle, the width x of the rectangle is 50mm, and the height y is 30mm.

The height m of the upper end of the microporous ceramic rod 2 protruding from the upper surface of the ladle nozzle block body 1 is 5 mm, and the height n of the bottom end of the microporous ceramic rod 2 extending into the air inlet box is 10 mm.

The microporous ceramic rod breathable upper nozzle block includes an iron ring 7, and the iron ring 7 is embedded in the surface layer of the lower part of the ladle nozzle block body 1, which effectively suppresses the problem of cracks caused by thermal stress of the ladle nozzle block body.

The iron ring 7 is a circular shape as a whole, the height L is 40mm, the distance a between the lower end of the iron ring and the lower end of the ladle nozzle block body 1 is 50mm, and the iron ring 7 is embedded in the ladle nozzle block body 1 The depth z in the surface layer is 10mm.

The iron ring 7 is welded with a 1mm thick iron sheet, the overlapping length of the joint is 40mm, and full welding is adopted.

The ladle nozzle seat brick body 1 is cast and formed with chrome corundum castables, the bulk density is ≥3.0g/cm ³ , the high-temperature flexural strength is ≥12Mpa, the high-temperature compressive strength is ≥80Mpa, the content of AL ₂ O ₃ is ≥ 92%, and the Cr ₂ O ₃ content ≥ 3%.

The microporous ceramic rod 2 adopts the existing extrusion molding, high temperature sintering, and is made of zirconia toughened corundum.

The longitudinal centerline of the flow steel hole 5 and the upper nozzle installation hole 6 is on a straight line with the longitudinal centerline of the ladle nozzle block body 1. The upper part of the flow steel hole 5 is a circular truncated shape, and the diameter of the upper port of the circular truncated d1. The diameter of the lower port is 203mm, the diameter d2 of the lower port is 152mm, and the height c of the circular cone is 65mm. The lower part of the flow steel hole 5 is a cylindrical channel, and the diameter of the lower cylindrical channel is consistent with the diameter of the lower port of the upper circular cone. .

The upper part of the runner installation hole 6 is truncated, and the fitting size of the runner installation hole is designed according to the external dimension of the runner.

The shape of the ladle nozzle seat brick body 1 is cylindrical, the outer diameter D of the cylinder is 380mm, and the height H of the cylinder is 470mm.

The material of the air inlet pipe 4 of the present invention is a heat-resistant stainless steel round pipe, the end of which is provided with a connecting thread, and the size is M16×1.5.

The invention also provides an argon blowing control device for LF refining ladle microporous ceramic rod air permeable upper nozzle block, which is provided with a set of argon gas pipeline system and electrical control system, and has manual blowing and air permeable nozzle block and automatic soft blowing mode Select the function, and introduce the molten steel weighing signal in the ladle, and adjust the argon flow synchronously according to the change of the net weight of the molten steel in the ladle, which realizes the precise control of the argon blowing flow of the permeable upper nozzle block.

The argon gas pipeline system, as shown in FIG. 4 , is divided into a main gas source circuit, an automatic branch circuit, a manual bypass circuit and a release branch circuit. ; Wherein the main gas source circuit sequentially includes the first ball valve 9a, the first pressure gauge 10a, the first gas filter 11a1, the second gas filter 11a2, the pressure regulator 12, and the first pressure sensor 15a in the main gas source circuit; The circuit sequentially includes the automatic branch second ball valve 9b1, the first solenoid valve 13b, the metallurgical special mass flow controller 14, the second pressure sensor 15b, the second pressure gauge 10b, and the automatic branch third ball valve 9b2; the manual bypass sequentially includes Manual bypass fourth ball valve 9c, manual regulating valve 16; manual bypass is connected in parallel with the second ball valve 9b1 of the automatic branch, the second solenoid valve 13b, and the metallurgical special mass flow controller 14, used for automatic branch failure, For manual operation applications, the argon pipeline system involved in the present invention is also used for the high pressure blow-through before the LF refining ladle microporous ceramic rod breathable upper nozzle block brick is automatically blown with argon. The branch circuit includes the second solenoid valve 13c and the exhaust throttle valve 17 in sequence, and is used for exhausting and depressurizing when the intake metal hose connected to the ventilation upper nozzle seat brick needs to be pulled out.

The electrical control system adopts the existing technology, including network switch, argon blowing control system PLC, touch screen, continuous casting basic automation system, argon blowing control system PLC, touch screen set in the control box, argon blowing control system PLC, touch screen, The basic automation system of continuous casting is connected to the network switch through Ethernet communication. The molten steel weighing system in the ladle collects and sends the weight of molten steel in the ladle to the basic automation system of continuous casting, and uploads it to the argon blowing control system through Ethernet communication and network switch. PLC, as shown in Figure 5.

The components in the argon pipeline system are all purchased from the market, wherein the ball valve 9 (including the first ball valve 9a of the main gas source, the second ball valve 9b1 of the automatic branch, the third ball valve 9b2 of the automatic branch, manual bypass The model specification of the fourth ball valve 9c) is DN20 63bar 304SS G1; the model specification of the pressure gauge 10 (including the first pressure gauge 10a, the second pressure gauge 10b) is YT60, 2.5MPa; the gas filter 11 (including the first gas filter The model and specification of the gas filter 11a1 and the second gas filter 11a2) are AF60-F10, G1, the filter grade is 5um, the pressure is 3.0MPa, with manual drainage; the model and specification of the pressure regulator 12 is BK201-25, the pressure resistance is 40bar, and the The pressure range is 0.5-25bar; the model specification of the solenoid valve 13 (including the first solenoid valve 13b of the automatic main circuit and the second solenoid valve 13c of the release branch) is DC24V, G1/2MS; the model specification of the metallurgical mass flow controller 14 is FLOX[on]62, IP65, flow rate is 200NL/min; the model and specification of pressure sensor 15 (including the first pressure sensor 15a of the main air source and the second pressure sensor 15b of the automatic branch) is PT5403, 0-25bar G1/4 , 4-20mA 316L; the model specification of the manual regulating valve 16 is PN50; the model specification of the exhaust throttle valve 17 is G1/2MS, 25bar; the model specification of the gas bus bar 18 is 3.0MPa G1/2.

The electrical control system components are all purchased from the market, and the model specification of the PLC control system is Siemens S7 series, PLC S7200-Smart, including AI, AO, DI, DO and other accessories, and the model specification of the touch screen is Siemens 7-inch touch screen.

The present invention utilizes the argon blowing control method of the above-mentioned LF refining ladle microporous ceramic rod gas permeable upper nozzle block and argon blowing control device, comprising the following steps:

This embodiment is used for 130tLF refining ladle casting to produce ultra-low carbon aluminum killed steel DC04;

The first step is to measure the initial flow value of the ladle full ladle soft blowing before the initial application: when the ladle full ladle soft blowing in the late stage of LF refining in the prior art, close the argon gas of the original ladle bottom blowing air-permeable bricks, and connect the above-mentioned air-permeable water supply Adjust the argon gas flow of the mouth seat brick to gradually increase, observe the slight fluctuation of the molten steel level in the ladle, and the argon blowing flow value when the molten steel surface is not exposed is the initial flow value of the soft blowing when the ladle is full. The initial flow rate The value is 45NL/min;

In the second step, after the ladle is in the pouring position on the continuous casting ladle turntable, a metal hose is used to connect the air inlet pipe 4 of the above-mentioned breathable upper nozzle block with the gas source outlet of the argon gas control device, and the ladle is transferred to the pouring position to start pouring, After flowing down, immediately use the manual bypass in the argon gas pipeline system to blow through the above-mentioned gas-permeable upper nozzle block: by adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, gradually increase the pressure, each time Increase 3mbar until the above-mentioned ventilating upper nozzle block is blown through;

When there is a blockage of the permeable upper nozzle block, the second pressure gauge 10b shows that the pressure is greater than or equal to 1200 mbar. By adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, when the pressure is gradually increased, the second pressure gauge 10b shows that The pressure value continues to increase until the second pressure gauge 10b shows that the pressure value begins to decrease gradually after the vent block is blown through.

The third step is to choose different automatic soft blowing modes according to the different control requirements of inclusions in the steel:

Ultra-low carbon aluminum-killed steel DC04 is a high-end steel with strict inclusion control. Soft blowing mode C is selected: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main blowing mode in the argon gas pipeline system is used. Blow argon on the road, and adjust the argon flow linearly according to the change of the net weight of the molten steel in the ladle. The set value of the argon flow rate in the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the ladle is soft when the ladle is full in step 1. The initial flow value of blowing is 45NL/min+5NL/min. When the ladle has slag or slag detection system alarm, keep the flow rate at 5NL/min to blow argon, and stop blowing argon when the ladle is turned back to the continuous casting turntable for pouring. .

Example 2

With the LF refining ladle microporous ceramic rod breathable upper nozzle seat brick described in Example 1, the difference is:

The microporous ceramic rod 2 is cylindrical, the diameter d is 45 mm, and the height h of the ceramic rod is 180 mm. The number of ventilation holes in the microporous ceramic rod 2 is 120, and the inner diameter of the ventilation holes is 0.075 mm. The number of the microporous ceramic rods 2 is 6, which are evenly arranged in a ring shape, and the diameter of the ring ring is 320mm.

The air chamber box 3 is annular as a whole, and the air chamber box is a metal box made of 1.5mm steel plate. The cross section of the metal box is a rectangle, the width x of the rectangle is 60mm, and the height y is 40mm.

The height m of the upper end of the microporous ceramic rod 2 protruding from the upper surface of the ladle nozzle block body 1 is 10 mm, and the height n of the bottom end of the microporous ceramic rod 2 extending into the air inlet box is 5 mm.

The iron ring 7 is a circular ring as a whole, and the height L is 50mm. The distance a between the lower end of the iron ring and the lower end of the ladle nozzle seat brick body 1 is 60mm. 20mm.

The iron ring 7 is welded with a 1mm thick iron sheet, the overlapping length of the joint is 50mm, and full welding is adopted.

The material of the microporous ceramic rod is zirconia toughened corundum mullite.

The longitudinal centerline of the flow steel hole 5 and the upper nozzle installation hole 6 is on a straight line with the longitudinal centerline of the ladle nozzle block body 1. The upper part of the flow steel hole 5 is a circular truncated shape, and the diameter of the upper port of the circular truncated d1. The diameter of the lower port is 210mm, the diameter d2 of the lower port is 160mm, and the height c of the circular cone is 80mm. The lower part of the flow steel hole 5 is a cylindrical channel. .

The shape of the ladle nozzle block body 1 is cylindrical, the outer diameter D of the cylinder is 400mm, and the height H of the cylinder is 490mm.

The present invention utilizes the argon blowing control method of the above-mentioned LF refining ladle microporous ceramic rod gas permeable upper nozzle block and argon blowing control device, comprising the following steps:

This embodiment is used for 130tLF refining ladle casting to produce low carbon aluminum killed steel SPHC;

The first step is to measure the initial flow value of the ladle full ladle soft blowing before the initial application: when the ladle full ladle soft blowing in the late stage of LF refining in the prior art, close the argon gas of the original ladle bottom blowing air-permeable bricks, and connect the above-mentioned air-permeable water supply Adjust the argon gas flow of the mouth seat brick to gradually increase, observe the slight fluctuation of the molten steel level in the ladle, and the argon blowing flow value when the molten steel surface is not exposed is the initial flow value of the soft blowing when the ladle is full. The initial flow rate The value is 42NL/min;

In the second step, after the ladle is in the pouring position on the continuous casting ladle turntable, a metal hose is used to connect the air inlet pipe 4 of the above-mentioned breathable upper nozzle block with the gas source outlet of the argon gas control device, and the ladle is transferred to the pouring position to start pouring, After flowing down, immediately use the manual bypass in the argon gas pipeline system to blow through the above-mentioned gas-permeable upper nozzle block: by adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, gradually increase the pressure, each time Increase 5mbar until the above-mentioned ventilating upper nozzle block is blown through;

The third step is to choose different automatic soft blowing modes according to the different control requirements of inclusions in the steel:

Low-carbon aluminum-killed steel SPHC is a mid-end steel with inclusion control requirements, and soft blowing mode B is selected: After the above-mentioned breathable upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic soft blowing mode in the argon gas pipeline system is used. Blow argon on the main road, adjust the argon flow linearly according to the change of the net weight of molten steel in the ladle. The set value of argon flow during the pouring process of molten steel = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the ladle is soft when the ladle is full in step 1 The initial flow rate of blowing is 42NL/min+3NL/min. When the molten steel casting amount reaches 60% of the total molten steel in the ladle, keep the flow rate at 3NL/min and blow argon. When the ladle is turned back to the continuous casting turntable, it stops after the pouring position. Blow argon.

Example 3

With the LF refining ladle microporous ceramic rod breathable upper nozzle seat brick described in Example 1, the difference is:

The microporous ceramic rod 2 is cylindrical, the diameter d is 40 mm, and the height h of the ceramic rod is 160 mm. The number of ventilation holes in the microporous ceramic rod 2 is 105, and the inner diameter of the ventilation holes is 0.085 mm. The number of the microporous ceramic rods 2 is 8, which are evenly arranged in a circular ring, and the diameter of the circular ring is 310 mm.

The air chamber box 3 is a circular ring as a whole, and the air chamber box is a metal box made of 1.8mm steel plate. The cross section of the metal box is a rectangle, the width x of the rectangle is 55mm, and the height y is 35mm.

The height m of the upper end of the microporous ceramic rod 2 protruding from the upper surface of the ladle nozzle block body 1 is 7 mm, and the height n of the bottom end of the microporous ceramic rod 2 extending into the air inlet box is 7 mm.

The iron ring 7 is a circular ring as a whole, the height L is 45mm, the distance a between the lower end of the iron ring and the lower end of the ladle nozzle seat brick body 1 is 55mm, and the iron ring 7 is embedded in the ladle nozzle seat brick body 1 The inner depth z is 15mm.

The longitudinal centerline of the flow steel hole 5 and the upper nozzle installation hole 6 is on a straight line with the longitudinal centerline of the ladle nozzle block body 1. The upper part of the flow steel hole 5 is a circular truncated shape, and the diameter of the upper port of the circular truncated d1. The diameter of the lower port is 190mm, the diameter d2 of the lower port is 140mm, and the height c of the circular cone is 55mm. The lower part of the flow steel hole 5 is a cylindrical channel, and the diameter of the lower cylindrical channel is the same as the diameter of the lower port of the upper circular cone. .

The shape of the ladle nozzle seat brick body 1 is cylindrical, the outer diameter D of the cylinder is 390mm, and the height H of the cylinder is 480mm.

The present invention utilizes the argon blowing control method of the above-mentioned LF refining ladle microporous ceramic rod gas permeable upper nozzle block and argon blowing control device, comprising the following steps:

This embodiment is used for 130tLF refining ladle casting to produce Q345B;

The first step is to measure the initial flow value of the ladle full ladle soft blowing before the initial application: when the ladle full ladle soft blowing in the late stage of LF refining in the prior art, close the argon gas of the original ladle bottom blowing air-permeable bricks, and connect the above-mentioned air-permeable water supply Adjust the argon gas flow of the mouth seat brick to gradually increase, observe the slight fluctuation of the molten steel level in the ladle, and the argon blowing flow value when the molten steel surface is not exposed is the initial flow value of the soft blowing when the ladle is full. The initial flow rate The value is 40NL/min;

In the second step, after the ladle is in the pouring position on the continuous casting ladle turntable, a metal hose is used to connect the air inlet pipe 4 of the above-mentioned breathable upper nozzle block with the gas source outlet of the argon gas control device, and the ladle is transferred to the pouring position to start pouring, After flowing down, immediately use the manual bypass in the argon gas pipeline system to blow through the above-mentioned gas-permeable upper nozzle block: by adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, gradually increase the pressure, each time Increase by 7mbar until the above-mentioned ventilating upper nozzle block is blown through;

The third step is to choose different automatic soft blowing modes according to the different control requirements of inclusions in the steel:

Q345B is a low-end steel grade without inclusion control requirements. Soft blowing mode A is selected: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow argon. According to the change of the net weight of molten steel in the ladle, adjust the argon flow rate linearly. The set value of the argon gas flow during the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial flow value of the soft blowing when the ladle is full in step 1 40NL/min+2NL/min, when the molten steel casting amount reaches 30% of the total molten steel in the ladle, keep the flow rate at 2NL/min to blow argon, and stop blowing argon when the ladle is transferred back to the continuous casting turntable for pouring.

Comparative Example 1

The difference from Example 1 is that the ladle breathable nozzle seat brick disclosed in Example 1 in Chinese patent document CN104028739B (patent number: 201410274221.8) is used to replace the microporous ceramic rod breathable nozzle seat involved in Example 1 of the present invention. Bricks, everything else is the same.

Comparative Example 2

The difference from Example 2 is that the ladle breathable nozzle seat brick disclosed in Example 2 in Chinese patent document CN104028739B (patent number: 201410274221.8) is used to replace the microporous ceramic rod breathable nozzle seat involved in Example 2 of the present invention. Bricks, everything else is the same.

Comparative Example 3

The difference from Example 3 is that the ladle breathable nozzle seat brick disclosed in Example 3 in Chinese patent document CN104028739B (patent number: 201410274221.8) is used to replace the microporous ceramic rod breathable nozzle seat involved in Example 3 of the present invention. Bricks, everything else is the same.

Comparative Example 4

The difference from Embodiment 2 is that the argon blowing control method of the nozzle block brick is different, and the argon blowing control method of the ladle circular seam type air permeable upper nozzle block brick disclosed in the embodiment 2 of Chinese patent document CN109719290 (application number: 2019101296742.1) is used. , instead of the argon blowing control method of the ladle microporous ceramic rod breathable upper nozzle block brick involved in the second embodiment of the present invention, and others are the same.

Experimental example

The application of the technical solutions involved in Examples 1-3 and Comparative Examples 1-4 in the production of ultra-low carbon aluminum-killed steel DC04, low-carbon aluminum-killed steel SPHC and plain carbon steel Q345B in a slab continuous casting machine of a steelmaking plant For comparison, large-scale electrolytic samples were taken at 1/4 of the casting billet, and processed into round bars with a diameter of 60 mm and a height of 100 mm, and the large-scale electrolytic inclusions were detected and compared. The same slag detection system is used for the molten steel pouring allowance of the killed steel DC04. The comparison results are shown in Table 1 below.

Table 1

Through the comparison of the data in Table 1 above, the application of the ladle microporous ceramic rod air permeable nozzle seat brick involved in the present invention is not easy to block, and it is easy to blow through, compared with the ladle air permeable nozzle seat brick involved in the comparative example CN104028739A (patent number: 201410274221.8). The weight of electrolytic inclusions in the continuous casting billet sample was reduced by more than 20% year-on-year, the average temperature drop of the steel level in the ladle was reduced by more than 0.1°C/min year-on-year, and the burn-free oxygen purging rate of the ladle’s air-permeable upper nozzle block brick was increased by more than 4% year-on-year. The balance is reduced by more than 20% year-on-year, and the average life of the ladle nozzle block brick is increased by 4 heats compared with the same period last year; the application of the argon blowing control method for the ladle permeable upper nozzle block brick involved in the present invention is compared with the application of the ladle involved in the comparative example CN109719290A (application number: 2019101296742.1). The argon blowing control method for the permeable upper nozzle block, the average temperature drop of the steel level in the ladle is reduced by 0.06℃/min year-on-year, the one-time blow-through rate of the ladle permeable nozzle block is increased by 11% year-on-year, and the ladle permeable nozzle block is free from oxygen-burning blowing The scan rate increased by 13% year-on-year.

Taking the slab continuous casting tundish of a steelmaking plant as the same experimental research object, according to the same research method, the ladle microporous ceramic rod air permeable upper nozzle seat brick according to the present invention and the Chinese patent document CN109719290A (application number: 2019101296742.1) were investigated. The water model experiment and numerical model study of the above-mentioned ladle ring seam vented upper nozzle block are carried out. The research results of the water model experiment show that when the simulated air blowing volume under normal process conditions is 3NL/min, the current measured in the water model experiment is 3NL/min. The diameter of the bubble near the ceramic rod of the invention is less than 1.8mm, while the diameter of the bubble near the annular seam described in Chinese patent document CN109719290A is less than 2mm; The removal rate of inclusions is 54-67%, while the removal rate of inclusions in the ladle circular seam type air permeable upper nozzle block brick described in Chinese patent document CN109719290 is 37-48%.

Through the water model experiment and the numerical model research, the advantages of the argon blowing metallurgical effect of the ladle microporous ceramic rod permeable upper nozzle block brick of the present invention are obvious.

Claims (17)

1. An LF refined ladle microporous ceramic rod permeable upper nozzle block brick, comprising a ladle nozzle block body (1), a microporous ceramic rod (2), an air chamber box (3), an air intake pipe (4), a flow steel hole ( 5), the upper nozzle mounting hole (6); it is characterized in that:

   The flow steel hole (5) and the upper nozzle installation hole (6) are connected up and down, and are installed in the middle of the ladle nozzle seat brick body (1);

   The air chamber box (3) is embedded in the surface layer of the upper part of the ladle nozzle block body (1); the air chamber box (3) is provided with a plurality of sockets (8), and the sockets (8) are used for fixing the microporous ceramic rod ( 2);

   There are a plurality of microporous ceramic rods (2), which are uniformly arranged in the ladle nozzle block body (1) in a ring shape, and the top of each microporous ceramic rod (2) protrudes out of the ladle nozzle block body (1). On the upper surface, the bottom end of each microporous ceramic rod (2) extends into the air chamber box (3), and the shape, number and position of the sockets (8) correspond to those of the microporous ceramic rod (2);

   One end of the air inlet pipe (4) is connected to the side part of the air chamber box (3), and the other end extends from the side part of the ladle nozzle block body (1).
2. The nozzle seat brick according to claim 1, characterized in that the microporous ceramic rod (2) is cylindrical, the diameter d is 35-45 mm, and the height h of the ceramic rod is 140-180 mm.
3. The nozzle seat brick according to claim 1, characterized in that, the microporous ceramic rod breathable upper nozzle seat brick further comprises an iron ring (7), and the iron ring (7) is embedded in the ladle nozzle seat brick body (1) in the lower surface.
4. The nozzle block brick according to claim 3, characterized in that, the iron ring (7) is a circular ring as a whole, the height L is 40-50 mm, and the distance between the lower end of the iron ring and the lower end of the ladle upper nozzle block body (1) a is 50-60 mm, and the iron ring (7) is buried in the inner surface layer of the ladle nozzle seat brick body (1) with a depth z of 10-20 mm.
5. The nozzle seat brick according to claim 3, characterized in that, the iron ring (7) is welded with a 1mm thick iron sheet, the overlapping length of the joint is 40-50mm, and full welding is adopted.
6. The nozzle block according to claim 1, characterized in that the microporous ceramic rod (2) is provided with ventilation holes along the axial direction of the microporous ceramic rod, and on the cross section of the microporous ceramic rod Evenly distributed, the number of ventilation holes is 60-120, the inner diameter of the ventilation holes is 0.075-0.1mm, and the ventilation holes longitudinally penetrate the upper and lower end surfaces of the microporous ceramic rod;

   Preferably, the number of the microporous ceramic rods (2) is 6-10, which are evenly arranged in an annular shape, and the diameter of the annular ring is 300-320 mm;
7. The nozzle seat brick according to claim 1, characterized in that the height m of the upper end of the microporous ceramic rod (2) protruding from the upper surface of the ladle nozzle seat brick body (1) is 5-10 mm, and the The height n of the bottom end of the hole ceramic rod (2) extending into the air chamber box is 5-10 mm.
8. The nozzle seat brick according to claim 1, wherein the microporous ceramic rod (2) is extruded and fired at high temperature, and the material is zirconia toughened corundum or zirconia toughened corundum mullite .
9. The nozzle block according to claim 1, characterized in that, the air chamber box (3) is in the shape of a circular ring as a whole, and the air chamber box is made of a metal box with a thickness of 1.5-2.0 mm, and the longitudinal direction of the metal box is The cross section is a rectangle, the width x of the rectangle is 50-60mm, and the height y is 30-40mm; the cross-section of the metal box is a ring, and a plurality of sockets (8) are evenly distributed on the ring.
10. The nozzle seat brick according to claim 1, characterized in that, the ladle nozzle seat brick body (1) is cast and formed by chrome corundum castable, the bulk density is ≥ 3.0g/cm ³ , the high temperature flexural strength is ≥ 12Mpa, and the high temperature Compressive strength ≥80Mpa, AL ₂ O ₃ content ≥ 92%, Cr ₂ O ₃ content ≥ 3%;
11. The nozzle block according to claim 1, characterized in that the longitudinal centerline of the flow steel hole (5) and the upper nozzle mounting hole (6) is in a straight line with the longitudinal centerline of the ladle nozzle block body (1). Above, the upper part of the flow steel hole (5) is a truncated cone, the diameter d1 of the upper port of the round table is 190-210mm, the diameter d2 of the lower port is 140-160mm, and the height c of the round table is 55-80mm. The lower part of the hole (5) is a cylindrical channel, the diameter of the lower cylindrical channel is the same as the diameter of the lower port of the upper circular table, and the cylinder height b is 250-270 mm;
12. The nozzle seat brick according to claim 1, characterized in that, the upper part of the nozzle mounting hole (6) is truncated, and the fitting size of the nozzle mounting hole is designed according to the external dimension of the nozzle;

    The shape of the ladle nozzle seat brick body (1) is cylindrical, the cylindrical outer diameter D is 380-400 mm, and the cylindrical height H is 470-490 mm.
13. An argon blowing control device for a permeable upper nozzle block, which is characterized in that a set of argon gas pipeline system and an electrical control system is provided, and has a function module for manually blowing through the permeable nozzle block and automatic soft blowing mode selection, and receiving a ladle Internal molten steel weighing signal, calculate the change of the net weight of molten steel in the ladle and adjust the argon flow synchronously;

    The breathable upper nozzle seat brick is the microporous ceramic rod breathable upper nozzle seat brick according to claim 1 .
14. The argon blowing control device according to claim 13, wherein the argon gas pipeline system is divided into a main gas source circuit, an automatic branch circuit, a manual bypass and a release branch, and the main gas source circuit, the automatic branch circuit and the The manual bypass is communicated through the gas bus (18), where

    The main gas source circuit includes in sequence a first ball valve (9a), a first pressure gauge (10a), a first gas filter (11a1), a second gas filter (11a2), a pressure regulator (12), a first pressure sensor (15a),

    The automatic branch circuit sequentially includes a second ball valve (9b1) of the automatic branch circuit, a first solenoid valve (13b), a metallurgical special mass flow controller (14), a second pressure sensor (15b), a second pressure gauge (10b), an automatic Branch third ball valve (9b2),

    The manual bypass sequentially includes the fourth manual bypass ball valve (9c) and the manual regulating valve (16),

    The manual bypass is connected in parallel with the second ball valve (9b1), the second solenoid valve (13b), and the metallurgical special mass flow controller (14) of the automatic branch, and is used for manual operation after the automatic branch fails.

    A release branch is arranged at the rear end of the manual regulating valve (16), which in turn includes a second solenoid valve (13c) and an exhaust throttle valve (17). Exhaust and depressurize when plugging in.
15. The argon blowing control device according to claim 13, wherein the electrical control system comprises a network switch, an argon blowing control system PLC, a touch screen, and a continuous casting basic automation system,

    The argon blowing control system PLC and touch screen are installed in the control box. The argon blowing control system PLC, touch screen and continuous casting basic automation system are all connected to the network switch through Ethernet communication. The molten steel weighing system in the ladle collects and sends the weight of the molten steel in the ladle. To the basic automation system of continuous casting, it is uploaded to the PLC of the argon blowing control system through Ethernet communication and network switch.
16. A kind of argon blowing control method is characterized in that comprising the steps:

    The first step is to apply the argon blowing control device of claim 13 for the first time, and measure the initial flow value of the soft blowing of the ladle full ladle breathable upper nozzle seat brick; the breathable upper nozzle seat brick is the microporous ceramic rod breathable according to claim 1 Shuikou block brick;

    In the second step, after the ladle is in the pouring position on the continuous casting ladle turntable, a metal hose is used to connect the air inlet pipe (4) of the gas permeable upper nozzle block with the gas source outlet of the argon gas control device, and the ladle is transferred to the pouring position to open. After pouring and flowing down, immediately use the manual bypass in the argon gas pipeline system to blow through the above-mentioned breathable upper nozzle block: by adjusting the pressure regulator 12 of the main gas source circuit in the argon gas pipeline system, gradually increase the pressure, Increase by 1-10mbar each time until the above-mentioned ventilation upper nozzle block is blown through;

    In the third step, according to the different control requirements for inclusions in the steel, after blowing through in the second step, different automatic soft blowing modes are activated immediately, and the automatic main circuit in the argon gas pipeline system is used to blow argon. According to the change of the net weight of molten steel in the ladle, the linear Adjust the argon flow,

    Argon flow setting value in molten steel pouring process = net weight of remaining molten steel in ladle ÷ net weight of molten steel when ladle is full × initial flow value of soft blowing when ladle is full in step 1 + (2~5) NL/min,

    When the molten steel casting amount reaches 30-100% of the total molten steel in the ladle, keep the flow rate at 2-5NL/min and blow argon.
17. The argon blowing control method as claimed in claim 16, characterized in that, in step 1, the initial flow value of the soft blowing of the upper nozzle seat bricks when the ladle is full of air is measured: when the ladle is full of soft blowing in the later stage of LF refining in the prior art, it is closed. The original ladle bottom was blown with the argon gas of the breathable bricks, connected to the argon gas of the breathable upper nozzle block, and the argon flow was adjusted to gradually increase. It is the initial flow value of soft blowing when the ladle is full;

    In step 3, different automatic soft blowing modes are selected according to the different control requirements of inclusions in the steel:

    (1) For low-end steel grades without inclusion control requirements, use automatic soft blowing mode A: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow Argon, according to the change of the net weight of molten steel in the ladle, adjust the argon flow rate linearly, the set value of argon flow rate during the molten steel pouring = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial soft blowing when the ladle is full in step 1 The flow value is +(2~5)NL/min. When the molten steel casting amount reaches 30~40% of the total molten steel in the ladle, keep the flow rate at 2~5NL/min and blow argon. Stop blowing argon after the stage is ready for pouring;

    (2) For mid-end steel grades with inclusion control requirements, use soft blowing mode B: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow argon. , according to the change of the net weight of molten steel in the ladle, adjust the argon flow linearly, the set value of argon flow during the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial flow of the soft blowing when the ladle is full in step 2 value +(2~5)NL/min, when the molten steel casting amount reaches 50~60% of the total molten steel in the ladle, keep the flow rate at 2~5NL/min and blow argon, when the ladle is poured, turn it back to the continuous casting turntable Stop blowing argon after pouring;

    (3) For high-end steel grades with strict inclusion control, soft blowing mode C is selected: After the above-mentioned ventilating upper nozzle block is blown through, the automatic soft blowing mode is immediately activated, and the automatic main circuit in the argon gas pipeline system is used to blow argon. The change of the net weight of molten steel in the ladle, adjust the argon flow rate linearly, the set value of argon gas flow during the molten steel pouring process = the net weight of the remaining molten steel in the ladle ÷ the net weight of the molten steel when the ladle is full × the initial flow value of the soft blowing when the ladle is full in step 2 + (2 to 5) NL/min, when the ladle has slag or slag detection system alarm, keep the flow rate of 2 to 5NL/min and blow argon.

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