Method for determining minimum inner diameter of ladle nozzle seating brick and ladle nozzle seating brick

Abstract

The invention provides a method for determining the minimum diameter of a ladle nozzle pocket block. The method comprises the steps that S1, a first device is incompletely embedded in a base of a second device; s2, the first device is filled with stuffing sand, molten steel is poured into a second device, and the molten steel is heated and subjected to heat preservation so that a sintering layer can be formed on the surface of the stuffing sand; s3, adjusting the diameter of the inner cavity of the first device, and repeating the steps to obtain a plurality of sintering layers; pressing the sintered layer until the sintered layer is broken, and recording a plurality of pressure values P; s4, calculating the molten steel static pressure P0 of the molten steel in the steel ladle to the ladle filler sand sintering layers in the bottom seating bricks of the steel ladles in the step S3 in the actual production process; and S5, relation curves of P-D and P0-D are drawn respectively, and the position of the intersection point of the two curves is the minimum inner diameter Dmin of the filler sand self-opening nozzle pocket block. According to the method, the minimum diameter, determined according to the method, of the ladle nozzle pocket block can effectively guarantee the self-opening rate of the ladle, and the method has high accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ladle nozzle seat bricks, in particular to a method for determining the minimum inner diameter of a ladle nozzle seat brick and a ladle nozzle seat brick. BACKGROUND

[0002] In the continuous casting process, whether the molten steel can be self-opened per furnace is a key factor affecting the production rhythm and the quality of molten steel. When the ladle is opened, if the drainage sand filled in the bottom of the ladle cannot be self-opened smoothly, the opening process needs to be completed through the oxygen burning operation, which not only leads to a significant extension of the opening process time, affecting the production rhythm, but also causes serious secondary oxidation of the molten steel, affecting the cleanliness of the molten steel.

[0003] In order to ensure the self-opening of the drainage sand when the ladle is opened, researchers have conducted relevant research on the structure of the drainage sand and the nozzle seat brick. Many studies have also been conducted in the field of patents, such as:

[0004] In terms of drainage sand, a Chinese patent with publication number CN115650740A discloses a high-quality magnesium drainage sand for ladles and a preparation method thereof. The prepared drainage sand has good flowability, high refractoriness, good high-temperature sintering performance, and high self-opening rate, thereby making the cleanliness of the molten steel higher and helping to further improve the quality of high-quality steel; a Chinese patent with publication number CN118420357A discloses a high self-opening rate refining drainage sand and a preparation method thereof. The prepared drainage sand has good flowability and low thermal expansion rate, appropriate sintering layer thickness, strong anti-permeation and anti-erosion, and can effectively improve the automatic opening rate; a Chinese patent with publication number CN118439875A discloses a ladle drainage sand and a production process thereof. By adding mullite sand and graphene, the drainage sand has moderate sintering layer thickness, stable composition, ensures the self-opening rate of the ladle, and is not prone to steel penetration.

[0005] In terms of the structure of the nozzle seat brick, a Chinese patent with publication number CN222221131U discloses a ladle nozzle seat brick for improving the self-opening rate of the ladle, which avoids the residual steel slag caused by the small platform on the inner wall of the water gap, greatly reduces the drainage frequency of the caster before the first five furnaces of the new ladle and the water gap hot change; a Chinese patent with publication number CN215033574U discloses a seat brick structure for improving the self-opening rate of the ladle, which replaces the original membrane structure by adding a bowl brick piece, compensates for the height difference between the ladle bottom pouring layer and the seat brick piece, and is not prone to produce steel slag and flow back into the water gap seat brick channel, thereby improving the self-opening rate of the ladle; a Chinese patent with publication number CN210254223U discloses a ladle water gap, which can effectively improve the self-opening rate of the ladle, enhance the sealing effect of the continuous casting protection pouring, prevent the absorption of oxygen and nitrogen by the molten steel, prevent the tumescence of the ladle protection sleeve, and improve the cleanliness of the molten steel.

[0006] The inner diameter size of the water gap base brick is a key parameter affecting the self-opening of the drainage sand; with the increase of the inner diameter, the sintered layer area formed by the contact surface of the drainage sand and the molten steel increases, the difficulty of the molten steel in the ladle to break the sintered layer by relying on the static pressure to realize the self-opening decreases, thereby helping to improve the self-opening rate of the ladle. However, with the increase of the inner diameter of the base brick, the weight of the drainage sand to be filled increases, and the pollution to the cleanliness of the molten steel intensifies. Therefore, in order to ensure the self-opening of the ladle drainage sand, while avoiding the serious pollution to the cleanliness of the molten steel caused by the excessive addition of the drainage sand, it is necessary to accurately determine the minimum inner diameter of the base brick to ensure the self-opening of the ladle. However, no related method is provided in the prior art. SUMMARY

[0007] The technical problem solved by the present application is to provide a method for determining the minimum inner diameter of the ladle water gap base brick. The minimum inner diameter of the ladle water gap base brick determined by the determination method provided in the present application can effectively ensure the self-opening rate of the ladle, and the method has high accuracy.

[0008] Therefore, the present application provides a method for determining the minimum diameter of the ladle water gap base brick, comprising the following steps:

[0009] S1, the first device is not completely embedded in the base of the second device, the shape of the first device is the same as the shape of the base of the ladle, and the inner cavity diameter D of the first device is the same as the inner cavity diameter of the base of the ladle;

[0010] S2, fill the drainage sand in the first device, pour the molten steel into the second device, so that the molten steel covers at least the top of the first device, heat and keep the molten steel, pour out the molten steel after keeping, and form a sintered layer on the surface of the drainage sand; the diameter of the sintered layer is the same as the inner cavity diameter D of the first device;

[0011] S3, adjust the inner cavity diameter of the first device according to the inner cavity diameters of a plurality of bases of the ladle, repeat steps S1-S2, and obtain a plurality of sintered layers corresponding to a plurality of bases of the ladle;

[0012] Press the sintered layer to break, and record a plurality of pressure values P;

[0013] S4, calculate the static pressure P0 of the molten steel in the ladle on the sintered layer of the drainage sand in the base of the ladle in the actual production process, and the calculation formula is as follows:

[0014] P0=π×(D 2 / 4)×ρ×g×H0×10 -9 ;

[0015] The inner cavity diameter of the base of the ladle is the same as the inner cavity diameter of the first device;

[0016] In the formula, P0 is the molten steel pressure borne by the sintered layer in the bottom block of the ladle, kN; π is the circular constant, 3.14 m / s 2 ; D is the inner diameter of the nozzle block at the bottom of the ladle, mm; ρ is the density of the molten steel, 7200 kg / m 3 ; g is the acceleration of gravity, 9.8 m / s 2 ; H0 is the depth of the molten steel in the ladle, m;

[0017] S5, draw the P-D relationship curve and the P0-D relationship curve in the same coordinate system respectively, and the intersection position of the two relationship curves is the minimum inner diameter D of the nozzle block self-opened by the drainage sand min .

[0018] In some specific embodiments, the height H2 of the first device exposed to the base of the second device is 100-250 mm, the inner cavity height H3 of the first device is 150-450 mm, the inner diameter D1 of the second device is 700-1200 mm, the inner cavity height H1 of the second device is 700-1000 mm, and the inner cavity diameter D is 250-600 mm.

[0019] In some specific embodiments, the temperature T of the heating is the same as the temperature of the transferred molten steel in the ladle in the actual production process, and the heat preservation time is the same as the molten steel transfer time in the actual production process.

[0020] In some specific embodiments, in step S2, during the molten steel pouring process, the molten steel flow is located at the gap position between the first device and the second device.

[0021] In some specific embodiments, the pressing process is specifically:

[0022] The sintered layer is placed horizontally on the pressure anvil, so that the center of the sintered layer and the center of the pressure anvil are on a vertical line, and the diameter D of the sintered layer is greater than the inner diameter D5 of the pressure anvil.

[0023] The center position of the sintered layer is pressed by the pressure rod until the sintered layer is crushed.

[0024] In some specific embodiments, D-D5 is 10-30 mm.

[0025] In some specific embodiments, the diameter D3 of the pressure rod is 20-40 mm.

[0026] In some specific embodiments, the D includes a series of values of 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 340 mm, 360 mm, 380 mm, 400 mm, 420 mm, 440 mm, 460 mm, 480 mm, 500 mm.

[0027] In some embodiments, the first device is a ladle bottom brick to simulate the actual production process; and the second device is a crucible.

[0028] The application also provides a ladle nozzle brick, the inner diameter size of which is greater than or equal to the inner diameter size determined by the method.

[0029] The application provides a method for determining the minimum inner diameter of a ladle nozzle brick, which first uses a simulation model to prepare a series of first devices with the same inner cavity diameter as the ladle bottom brick, then crushes the series of sintered layers to obtain a series of pressure values P corresponding to the sintered layer of the ladle bottom brick, then calculates the static pressure P0 of the molten steel in the ladle on the sintered layer of the drainage sand in the ladle bottom brick with the same inner cavity diameter, and finally draws the P-D curve of the simulation and the P0-D curve, and the intersection of the two curves is the minimum inner diameter D of the nozzle brick. min The method provided by the application determines the minimum inner diameter of the actual nozzle brick by using the P-D curve of the simulation model and the P0-D curve of the actual production, and realizes the determination of the minimum inner diameter of the nozzle brick through the accurate control of the simulation model, thereby ensuring the accuracy of the minimum inner diameter of the nozzle brick, and the small inner diameter of the nozzle brick determined by the application can effectively ensure the self-opening rate of the ladle and reduce the filling amount of the drainage sand and the pollution of the drainage sand to the molten steel. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the device for obtaining the sintered layer of the drainage sand.

[0031] Figure 2 The figure is a schematic diagram of the device for crushing the sintered layer.

[0032] Figure 3 The figure is a diameter-pressure curve diagram provided by the embodiment of the application. DETAILED DESCRIPTION

[0033] In order to further understand the application, the preferred embodiments of the application are described below in combination with the examples, but it should be understood that the description is only for further illustrating the features and advantages of the application, and is not a limitation on the claims of the application.

[0034] In view of the technical blank of the method for determining the minimum inner diameter of the ladle nozzle brick self-opened by the drainage sand in the prior art, the application provides a method for determining the minimum inner diameter of the ladle nozzle brick, which can accurately determine the minimum inner diameter of the ladle nozzle brick, effectively ensure the self-opening rate of the ladle drainage sand, and reduce the filling amount of the drainage sand; specifically, the embodiment of the application discloses a method for determining the minimum diameter of a ladle nozzle brick, which comprises the following steps:

[0035] S1, the first device is not completely embedded in the base of the second device, the shape of the first device is the same as the shape of the ladle bottom base brick, the inner cavity diameter D of the first device is the same as the inner cavity diameter of the ladle bottom base brick;

[0036] S2, fill the first device with drainage sand, pour molten steel into the first device, so that the molten steel covers at least the top of the first device, heat and keep the molten steel, pour out the molten steel after keeping, and form a sintered layer on the surface of the drainage sand; The diameter of the sintered layer is equal to the inner cavity diameter D of the first device;

[0037] S3, adjust the inner cavity diameter of the first device according to the inner cavity diameters of a plurality of ladle bottom base bricks, repeat steps S1-S2, and obtain a plurality of sintered layers corresponding to a plurality of ladle bottom base bricks;

[0038] The sintered layer is pressed to break, and a plurality of pressure values P are recorded;

[0039] S4, calculate the static pressure P0 of the molten steel in the ladle on the sintered layer of the drainage sand in the ladle bottom base brick in the actual production process, and the calculation formula is as follows:

[0040] P0=π×(D 2 / 4)×ρ×g×H0×10 -9 ;

[0041] In the formula, P0 is the molten steel pressure borne by the sintered layer in the ladle bottom base brick, kN; π is the circular constant, taking 3.14 m / s 2 ; D is the inner diameter of the ladle nozzle base brick, mm; ρ is the density of molten steel, taking 7200 kg / m 3 ; g is the acceleration of gravity, taking 9.8 m / s 2 ; H0 is the depth of molten steel in the ladle, m;

[0042] S5, draw the P-D relationship curve and the P0-D relationship curve in the same coordinate system respectively, and the intersection position of the two curves is the minimum inner diameter D min of the nozzle base brick opened by the drainage sand.

[0043] In the method for determining the minimum diameter of the ladle nozzle base brick, in step S1, a first device is incompletely embedded in a base of a second device, the first device has the same shape as the ladle bottom base brick, and the inner diameter D of the first device is the same as the inner cavity diameter of the ladle bottom base brick; in the present application, the first device is specifically a container, which simulates the ladle bottom base brick (ladle nozzle base brick) in the actual production process; the second device is specifically a crucible; the first device is used for placing drainage sand, and the second device has the first device placed inside, and the first device remains fixed in position when molten steel is poured into the second device. Specifically, the first device and the second device are devices with grooves, and the inner diameter size and the height are different; in some specific embodiments, the structural schematic diagram of the first device and the second device is as shown in Figure 1 Figure 1 In the structural schematic diagram, 1 is a crucible, 2 is a container, 3 is drainage sand, D1 is the inner diameter of the crucible, D is the inner diameter of the container, H1 is the inner cavity height of the crucible, H2 is the height of the container exposed to the base of the crucible, and H3 is the inner cavity height of the container, wherein the height H2 of the first device exposed to the base of the second device is 100-250 mm, the inner cavity height H3 of the first device is 150-450 mm, the inner diameter D1 of the second device is 700-1200 mm, the inner cavity height H1 of the second device is 700-1000 mm, and the inner cavity diameter D is 250-600 mm. Specifically, H2 is 150-200 mm, H3 is 250-400 mm, D1 is 800-1000 mm, and H1 is 800-900 mm. The above first device and second device are simulation devices, and the above dimensions are limited to ensure the feasibility of the simulation model and the accuracy of the test results.

[0044] In step S2, the first device is filled with drainage sand, molten steel is poured into the first device, the molten steel covers at least the top of the first device, the molten steel is heated and kept warm, the molten steel is poured out after being kept warm, and a sintered layer is formed on the surface of the drainage sand; the diameter of the sintered layer is equal to the inner cavity diameter D of the first device; in the above process, the first device is filled with drainage sand and completely filled with drainage sand, then molten steel is poured into the second device, and the molten steel completely immerses the first device to ensure the formation of the sintered layer; in order to avoid the molten steel stream directly impacting the drainage sand in the first device, the molten steel stream is located in the gap between the second device and the first device during pouring. After pouring, the molten steel is heated and kept warm, and then the molten steel is poured out, thereby forming a sintered layer on the surface of the drainage sand, and the diameter of the sintered layer is the same as the inner cavity diameter of the first device; the heating temperature T is the same as the temperature of the molten steel in the ladle in the actual production process, and the keeping warm time t is the same as the molten steel transfer time in the actual production process, that is, the above simulates the process of transferring the molten steel in the ladle to the nozzle, thereby ensuring the accuracy of the determination method.​

[0045] In actual production, the inner cavity diameter of the ladle bottom seat brick is not only 1, but also several different inner cavity diameters of the ladle bottom seat brick. In view of this, the inner cavity diameter D of the first device is adjusted, which can be several of 250 mm, 260 mm, 270 mm, 280 mm, 290 mm, 300 mm, 310 mm, 320 mm, 330 mm, 340 mm, 350 mm, 360 mm, 370 mm, 380 mm, 390 mm, 400 mm, 410 mm, 420 mm, 430 mm, 440 mm, 450 mm, 460 mm, 470 mm, 480 mm, 490 mm, 500 mm, 510 mm, 520 mm, 530 mm, 540 mm, 550 mm, 560 mm, 570 mm, 580 mm, 590 mm, 600 mm, and can also include several other unlisted above, on this basis, the above S1 and S2 steps are repeated, that is, several sintered layers corresponding to several ladle bottom seat bricks are obtained,

[0046] The above-mentioned several sintered layers are pressed in turn to be crushed, and the pressure value P of pressing to be crushed is recorded. In a specific embodiment, the device for pressing is shown in the schematic diagram Figure 2 , wherein 4 is a pressing rod, 5 is a drainage sand sintered layer, 6 is a pressure anvil, D3 is the diameter of the pressing rod, D is the diameter of the sintered layer, and D5 is the inner diameter of the pressure anvil. The process of pressing is specifically:

[0047] Place the sintered layer on the pressure anvil, so that the center of the sintered layer and the center of the pressure anvil are on a vertical line, and the diameter D of the sintered layer is greater than the inner diameter D5 of the pressure anvil;

[0048] Slowly apply pressure to the center position of the sintered layer through the pressing rod until the sintered layer is crushed.

[0049] In the above pressing process, D-D5 is 10-30 mm, and the diameter D3 of the pressing rod is 20-40 mm. Specifically, D-D5 is 15-20 mm, and the diameter D3 of the pressing rod is 25-35 mm. In the present application, the above D-D5 is preferably limited to make the diameter of the sintered layer slightly larger than the inner diameter of the pressure anvil, so as to ensure that the sintered layer can be placed on the pressure anvil, and avoid that the sintered layer falls into the inner cavity of the pressure anvil due to the too large inner diameter of the pressure anvil. The diameter of the pressing rod is limited to ensure that the pressure of the pressing rod can be accurately concentrated on the center position of the sintered layer. If the diameter of the pressing rod is too small, the bending deformation of the pressing rod may occur during the pressing process. If the diameter of the pressing rod is too large, it may be difficult to align the pressing rod with the center position of the sintered layer, and the contact area between the pressing rod and the sintered layer is too large, which increases the lateral frictional stress on the contact surface and affects the test results of the vertical pressure.

[0050] As described above, the first device corresponding to several sintered layers, after the above pressing, the first device with different inner cavity diameters corresponds to several pressure values.

[0051] In some embodiments, the sintered layer 1 of the first device 1 with the first inner cavity diameter can be prepared first, and the pressure value 1 corresponding to the inner cavity diameter can be obtained after pressing. Then, the sintered layer 2 of the first device 2 with the second inner cavity diameter can be prepared by repeating the above process, and the pressure value 2 corresponding to the inner cavity diameter can be obtained after pressing. The process is repeated in sequence to obtain a series of pressure values P corresponding to the inner cavity diameters H.

[0052] According to the present application, in step S4, the molten steel static pressure P0 of the molten steel in the ladle on the sintered layer of the drainage sand in the bottom block of the ladle is calculated, and the calculation formula is as follows:

[0053] P0=π×(D 2 / 4)×ρ×g×H0×10 -9 ;

[0054] In the formula, P0 is the molten steel pressure borne by the sintered layer in the bottom block of the ladle, kN; π is the circular constant, taking 3.14 m / s 2 ; D is the inner diameter of the nozzle block of the ladle, mm; ρ is the density of the molten steel, taking 7200 kg / m 3 ; g is the acceleration of gravity, taking 9.8 m / s 2 ; H0 is the depth of the molten steel in the ladle, m;

[0055] In the above static pressure P0, D corresponds to D in steps S1-S3 above, that is, the number and value of D in the first device in the simulation model are the same as the number and value of D in the bottom block of the ladle in the actual production in step S4.

[0056] According to the present application, in step S5, the P-D relationship curve and the P0-D relationship curve are finally drawn in the same coordinate system, and the intersection position of the two curves is the minimum inner diameter D min of the nozzle block of the drainage sand self-opening; in specific embodiments, the horizontal coordinate is the diameter, and the vertical coordinate is the pressure.

[0057] The present application also provides a ladle nozzle block, and the inner diameter size of the ladle nozzle block is greater than or equal to the inner diameter size determined by the determination method.

[0058] In order to further understand the present application, the determination method of the minimum inner diameter of the ladle nozzle block provided by the present application is described in detail below, and the protection scope of the present application is not limited by the following embodiments.

[0059] Example 220-ton ladle molten steel transfer process ensures the calculation and verification of the minimum diameter of the nozzle block of the drainage sand self-opening

[0060] (1) Steel and drainage sand contact area sintering layer preparation

[0061] (1.1) Figure 1 The structure diagram of the sintering layer preparation device is shown in Figure 1 The ladle bottom seat brick in the actual production process is simulated by the container. The inner diameter D of the container is equal to the inner diameter of the ladle seat brick in the actual production process. The actual container inner cavity diameter D used in sintering layer preparation includes 300 mm, 320 mm, 340 mm, …, 500 mm, a total of 11, the container height H2 = 200 mm, the container inner cavity height H3 = 250 mm, the inner diameter D1 of the crucible = 800 mm, and the inner cavity height H1 of the crucible = 900 mm.

[0062] (1.2) In Figure 1 The drainage sand is filled in the container inner cavity, and the molten steel is poured into the crucible. When the molten steel is poured into the crucible, the steel stream is located between the gap between the crucible and the container, so as to avoid direct impact of the steel stream on the drainage sand in the container.

[0063] (1.3) The molten steel poured in step (1.2) is continuously heated and kept in a vacuum induction furnace, so that the temperature is constantly maintained at T = 1600℃. T is the same as the temperature of the transferred molten steel in the ladle in the actual production process.

[0064] (1.4) After the molten steel in step (1.3) is heated and kept for t = 130 minutes (the same as the molten steel transfer time in the actual production process), the molten steel is poured out. At this time, a certain thickness of sintering layer is formed near the upper part of the initial pouring drainage sand and the molten steel contact surface. The sintering layer diameter is equal to the inner cavity diameter D of the container, including D = 300 mm, 320 mm, 340 mm, …, 500 mm, a total of 11 drainage sand sintering layers. After the sintering layer is cooled, it is taken out for standby use.

[0065] (2) Drainage sand sintering layer crushing test

[0066] (2.1) Figure 2 The structure diagram of the sintering layer crushing test device is shown in the figure, wherein the pressure rod diameter D3 = 20 mm, and D5 is the inner diameter of the pressure anvil, and D-D5 = 20 mm.

[0067] (2.2) The 11 different diameter drainage sand sintering layers prepared in step (1) are respectively placed on the pressure anvil, and the sintering layer is aligned with the center of the pressure anvil.

[0068] (2.3) Slowly apply pressure to the center position of the drainage sand sintering layer through the pressure rod until the drainage sand sintering layer is crushed. Record the sintering layer crushing pressure value P at this time. The actual measured crushing pressure P of the 11 drainage sand sintering layers is shown in Table 1.

[0069] Table 1 Measured bursting pressure data of drainage sand sintering layers with different diameters

[0070]

[0071] (3) Calculate the pressure of molten steel in the ladle on the drainage sand sintering layer

[0072] Based on formula (1), the static pressure P0 of the molten steel in the ladle on the drainage sand sintering layer in the seat bricks with different inner diameters (D = 300mm, 320mm, 340mm, ... 500mm) in the actual production process is calculated. The results are shown in Table 2.

[0073] P0=π×(D 2 / 4)×ρ×g×H0×10 -9 (1);

[0074] Where P0 is the molten steel pressure on the sintered layer of the block, in kN; π is the pi, which is 3.14 m / s 2 ; D is the inner diameter of the ladle nozzle brick (with Figure 1 The inner diameter of the container is equal), D = 300mm, 320mm, 340mm, ... 500mm, a total of 11 different inner diameters; ρ is the density of molten steel, which is 7200kg / m 3 ; g is the acceleration due to gravity, which is 9.8m / s 2 ; H0 is the depth of molten steel in the ladle, which is 4.2m.

[0075] Table 2 Static pressure of molten steel on the drainage sand sintered layer in block bricks with different inner diameters

[0076]

[0077]

[0078] (4) Determine the minimum inner diameter of the ladle nozzle seat brick to ensure the drainage sand opens automatically

[0079] The crushing pressure P corresponding to the drainage sand sintered layer with different diameters (D) determined by actual measurement in step (2.3) and the molten steel static pressure P0 of the drainage sand sintered layer in the nozzle seat brick with different inner diameters (D) determined by calculation in step (3) are plotted in a "diameter-pressure" diagram with the horizontal axis being the diameter and the vertical axis being the pressure, as shown in the figure: Figure 3 As shown in the figure, the horizontal coordinate corresponding to the intersection of the two curves "DP" and "D-P0" is the minimum inner diameter D of the water nozzle seat brick to ensure the self-opening of the drainage sand. min , it can be seen from the figure that D min =399.2mm, thus the minimum inner diameter D of the nozzle seat brick is obtained min =399.2mm.

[0080] To verify D minThe accuracy of the D = 399.2 mm, in actual production process, for ladle with different inner diameter nozzle seat brick, tracking statistics of the flow sand self-opening, the results are shown in Table 3;

[0081] Table 3 tracking statistics of the flow sand self-opening of the ladle

[0082] Seat brick inner diameter D, mm Number of furnaces Number of self-starting furnaces Number of non-self-starting furnaces Self-starting rate, % 360 20 6 14 30 380 20 10 10 50 400 20 19 1 95 420 20 20 0 100 440 20 20 0 100 460 20 20 0 100

[0083] From Table 3, it can be seen that when the inner diameter of the seat brick is increased from below 400 mm to 400 mm, the self-opening rate is greatly increased to 95%, and when the inner diameter of the seat brick is above 400 mm, the self-opening rate reaches 100%, thereby proving the accuracy of the D = 399.2 mm determined by the present application. min

[0084] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0085] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.​

Claims

1. A method for determining the minimum diameter of a ladle nozzle seat brick, comprising the following steps: S1. Partially embedding the first device in the base of the second device, wherein the shape of the first device is the same as the shape of the ladle bottom base brick, and the inner cavity diameter D of the first device is the same as the inner cavity diameter of the ladle bottom base brick; S2. Fill the first device with drainage sand, pour molten steel into the second device until the molten steel covers at least the top of the first device, heat the molten steel and keep it warm, pour out the heated molten steel, and form a sintered layer on the surface of the drainage sand; the diameter of the sintered layer is the same as the inner diameter D of the first device; S3, adjusting the inner cavity diameter of the first device according to the inner cavity diameters of the plurality of ladle bottom seat bricks, repeating steps S1 to S2, and obtaining a plurality of sintered layers corresponding to the plurality of ladle bottom seat bricks; Press the sintered layer until it breaks, and record several pressure values ​​P; S4. Calculate the static pressure P0 of the molten steel in the ladle on the drainage sand sintering layer in the base brick at the bottom of the ladle during actual production. The calculation formula is as follows: P0=π×(D 2 / 4)×ρ×g×H0×10 -9 ; The inner diameter of the base brick at the bottom of the ladle is the same as the inner diameter of the first device; Where P0 is the molten steel pressure on the sintered layer of the ladle bottom brick, kN; π is the pi, which is 3.14m / s 2 ; D is the inner diameter of the water nozzle brick at the bottom of the ladle, mm; ρ is the density of molten steel, which is 7200kg / m 3 ; g is the acceleration due to gravity, which is 9.8m / s 2 ; H0 is the depth of molten steel in the ladle, m; S5. Draw the PD relationship curve and the P0-D relationship curve in the same coordinate system. The intersection of the two relationship curves is the minimum inner diameter D of the water inlet brick of the drainage sand self-opening min .

2. The determination method according to claim 1, characterized in that The height H2 of the first device exposed from the base of the second device is 100-250 mm, the inner cavity height H3 of the first device is 150-450 mm, the inner diameter D1 of the second device is 700-1200 mm, the inner cavity height H1 of the second device is 700-1000 mm, and the inner cavity diameter D is 250-600 mm.

3. The determination method according to claim 1, characterized in that The heating temperature T is the same as the transfer temperature of the molten steel in the ladle during actual production, and the holding time is the same as the transfer time of the molten steel during actual production.

4. The determination method according to claim 1, characterized in that In step S2, during the molten steel pouring process, the molten steel stream is located in the gap between the first device and the second device.

5. The determination method according to claim 1, characterized in that: The specific process of the pressing is: Placing the sintered layer flat on the anvil so that the center of the sintered layer and the center of the anvil are on a vertical line, and the diameter D of the sintered layer is larger than the inner diameter D5 of the anvil; A pressure rod is used to apply pressure to the center of the sintered layer until the sintered layer is broken.

6. The determination method according to claim 5, characterized in that: D-D5 is 10~30mm.

7. The determination method according to claim 5, characterized in that: The diameter D3 of the pressure rod is 20-40 mm.

8. The determination method according to any one of claims 1 to 7, characterized in that: The D includes a series of values ​​including 240mm, 260mm, 280mm, 300mm, 320mm, 340mm, 360mm, 380mm, 400mm, 420mm, 440mm, 460mm, 480mm, and 500mm.

9. The determination method according to any one of claims 1 to 7, characterized in that: The first device is a container to simulate the bottom brick of the ladle in the actual production process; the second device is a crucible.

10. A ladle nozzle seat brick, wherein the inner diameter of the ladle nozzle seat brick is greater than or equal to the inner diameter determined by the determination method according to any one of claims 1 to 9.

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