A continuous casting argon blowing plug rod and its preparation method and application

Abstract

The present invention discloses a continuous casting argon blowing stopper rod and its preparation method and application, which belong to the technical field of steelmaking and continuous casting. The stopper rod includes a stopper rod body and a stopper rod head located at the front end of the stopper rod body, and the stopper rod head is made of mesoporous material; a tubular argon gas channel leading to the stopper rod head is provided in the stopper rod body, and two or more spherical air chambers connected to the tubular argon gas channel and arranged adjacently in the vertical direction are provided inside the stopper rod head, and the volume of each spherical air chamber gradually decreases from top to bottom, and an anti-scouring layer is distributed circumferentially on the outer side wall of the connection between the stopper rod body and the stopper rod head; and the mesoporous material and the anti-scouring layer are special formula raw materials designed by the present invention. The stopper rod can completely eliminate the problem of argon blowing concentration, ensure that argon gas with a stable flow rate is diffusely blown into the molten steel, and form small and uniform bubbles to eliminate the influence of large bubbles on the crystallizer liquid level fluctuation, and effectively remove the flocculent inclusions on the rod head, improve the flow control accuracy, enhance the argon blowing effect, and purify the quality of the molten steel.

Description

Technical Field

[0001] The invention relates to using a stopper rod to blow argon in a continuous casting process to improve a water nozzle casting state, belongs to the technical field of steelmaking continuous casting, and specifically relates to a continuous casting argon blowing stopper rod and a preparation method and application thereof. Background Art

[0002] The stopper rod is one of the "three major parts" of steelmaking and continuous casting, and is a functional refractory material for continuous casting. The stopper rod mainly plays the role of opening and closing the tundish. In addition to being able to automatically control the flow of molten steel from the tundish to the crystallizer in conjunction with the submerged nozzle or upper nozzle, the stopper rod can also be used to blow argon and other inert gases into the tundish through the argon blowing function of the stopper rod. The stopper rod has the functions of controlling the steel flow and purifying the molten steel. The stopper rod is in a closed state when pouring is started and stopped, and is usually in an open state.

[0003] There are two main types of stopper rods: combined stopper rods and integral stopper rods. Due to the large number of joints and installation reasons, molten steel and slag can easily corrode the joints of combined stopper rods, causing the rod to break or the plug head to fall off; integral stopper rods can avoid the above problems and disadvantages. Among argon-blown stopper rods, the commonly used structural forms are single-hole type and multi-hole type argon-blown stopper rods, that is, there are different numbers of gas guide holes on the stopper rod head, and these gas guide holes are connected to the argon gas channel in the stopper rod body. During use, the argon gas blown in through the air guide holes is relatively concentrated, and large bubbles are easily formed in the molten steel, resulting in fluctuations in the liquid level of the crystallizer and slag rolls, which poses a risk of steel leakage. At the same time, the argon gas blown in through the air guide holes is unevenly distributed and cannot effectively remove the flocculent inclusions initially deposited on the surface of the stopper head. As the flocculent inclusions continue to aggregate and become larger inclusions, they are washed off by the steel flow and enter the crystallizer, causing an overflow accident in the crystallizer. In addition, impurities in the molten steel are easily deposited on the surface of the stopper head, affecting the flow control accuracy of the stopper head, and cannot be closed normally when pouring is stopped, resulting in a risk of steel leakage. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a continuous casting argon blowing stopper rod and its preparation method and application. The stopper rod can completely eliminate the problem of argon blowing concentration, ensure that argon gas with a stable flow rate is diffusely blown into the molten steel, form small and uniform bubbles, eliminate the influence of large bubbles on the crystallizer liquid level fluctuation, and effectively remove flocculent inclusions on the rod head, improve the flow control accuracy, enhance the argon blowing effect, and purify the quality of the molten steel.

[0005] To achieve the above technical objectives, the present invention discloses a continuous casting argon blowing stopper rod, which comprises a stopper rod body and a stopper rod head located at the front end of the stopper rod body, wherein the stopper rod head is made of a mesoporous material; a tubular argon gas passage leading to the stopper rod head is provided in the stopper rod body, and two or more spherical gas chambers connected to the tubular argon gas passage and arranged adjacent to each other in the vertical direction are provided inside the stopper rod head, wherein the volume of each spherical gas chamber gradually decreases from top to bottom, and an anti-scouring layer is distributed circumferentially on the outer side wall of the connection between the stopper rod body and the stopper rod head;

[0006] Wherein, the mesoporous material is prepared from the following raw materials in the following weight percentages:

[0007] Sintered corundum 40% to 77%, mesoporous corundum 10% to 30%, graphite 3% to 10%, activated alumina 2% to 5%, microporous zirconium aluminum oxide 5% to 10%, resin 3% to 8%, the added diluent is 0.5% to 3% of the total of all raw materials of the mesoporous materials, and the antioxidant is 0.3% to 3% of the total of all raw materials of the mesoporous materials;

[0008] The anti-scour layer comprises the following raw materials in weight percentage:

[0009] Zirconia corundum 30%-65%, zircon sand 20%-40%, graphite 3%-10%, activated alumina 2%-5%, spinel 5%-10%, resin 5%-8%, antioxidant 0.5%-3%.

[0010] Furthermore, the apparent porosity of the mesoporous material is ≥18%, and the median diameter of the pores is ≤50 nm.

[0011] Furthermore, the mesoporous material is prepared from the following raw materials in weight percentage:

[0012] Sintered corundum 77%, mesoporous corundum 10%, graphite 3%, activated alumina 2%, microporous zirconium aluminum oxide 5%, resin 3%, additional diluent 0.5%, antioxidant 0.3%.

[0013] Furthermore, the volume density of the anti-scour layer and the stopper rod body is ≥3.2 g / cm 3 .

[0014] Furthermore, the anti-scour layer comprises the following raw materials in percentage by weight:

[0015] Zirconia corundum 30%, zircon sand 40%, graphite 10%, activated alumina 5%, spinel 10%, resin 5%, and the added antioxidant is 3% of the total of all raw materials of the anti-scour layer.

[0016] Furthermore, the microporous zirconium aluminum oxide is a zirconium aluminum oxide crystalline microporous material with high stability and high specific surface area.

[0017] The resin is a conventional liquid thermosetting phenolic resin used in the production of continuous casting three large parts.

[0018] The added diluent is one or more alcohol or ketone organic solvents;

[0019] The antioxidant is one or more of boron carbide, silicon carbide, metal aluminum and metal silicon.

[0020] Furthermore, the maximum length of the spherical air chamber with the largest volume in the horizontal direction is not greater than 40% of the length of the stopper rod head on the same horizontal line, and the maximum length of the spherical air chamber with the smallest volume in the horizontal direction is not less than the diameter of the tubular argon gas channel;

[0021] The distance between the bottom end of the spherical air chamber with the smallest volume and the bottom end of the stopper rod head is 25-40% of the height of the stopper rod head.

[0022] Furthermore, the vertical axes of the spherical gas chambers are on the same straight line and coincide with the vertical axis of the tubular argon gas channel.

[0023] Furthermore, the scouring layer consists of a body scouring portion and a rod head scouring portion, the height of the body scouring portion is 30-80 mm, the height of the rod head scouring portion is 30-80% of the height of the stopper rod head, and the thickness of the scouring layer is 25%-40% of the wall thickness of the stopper rod body.

[0024] Another technical purpose of the present invention is to disclose a method for preparing the stopper rod, which comprises the following steps:

[0025] 1) Ingredients: The various parts of the stopper rod are mixed with various raw materials according to the weight ratio according to the ingredient list;

[0026] 2) Mixing and granulation: put the prepared raw materials into a granulator for mixing and granulation;

[0027] 3) Material trapping: Place the prepared materials in the material trapping room, ensure that the temperature in the trapping room is 20-25°C, the humidity is less than 40%, and the trapping time is 18-24h;

[0028] 4) Molding: Add the trapped plug body material, plug head material, and anti-scouring layer material into the mold respectively, and mold them in an isostatic pressing device with a molding pressure of 120-140MPa;

[0029] 5) Drying: Dry the formed plug rod in a drying kiln at 220-250°C for 18-24 hours;

[0030] 6) Firing: Place the stopper rod in a reducing atmosphere firing kiln at 1100-1200°C for 5-6 hours;

[0031] 7) Machining: Turn the fired stopper rod according to the size requirements of the drawing;

[0032] 8) Coating: evenly coat the outside of the stopper rod with an anti-oxidation coating with a coating thickness of 0.15 to 0.3 mm;

[0033] 9) Flaw detection: Perform X-ray flaw detection on the stopper rod;

[0034] 10) Packaging: Finished products will be packaged after passing the inspection.

[0035] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0036] 1. The present invention provides a spherical air chamber inside the plug rod head, and the volume of each spherical air chamber gradually decreases from top to bottom, which is beneficial to buffering the argon gas flow and improving the stability of the argon gas flow.

[0037] 2. The anti-scour layer of the present invention is made of a material with a relatively high density, and the outer wall of the contact portion between the body and the club head is integrally formed with the same anti-scour layer, thereby improving the firmness of the combination between the body and the club head.

[0038] 3. The plug rod head of the present invention is made of mesoporous material. Under the premise of ensuring the overall strength of the rod head, argon gas is diffusely blown into the molten steel to form small and uniform bubbles, so as to eliminate the influence of large bubbles on the liquid level fluctuation of the crystallizer, and can effectively remove flocculent inclusions on the rod head, improve the flow control accuracy, enhance the argon blowing effect, and purify the quality of the molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A longitudinal cross-sectional view of a continuous casting argon blowing stopper rod designed for an embodiment of the present invention;

[0040] in, Figure 1 The parts numbers are as follows:

[0041] The stopper rod body 1, the stopper rod head 2, the tubular argon gas channel 3, the spherical gas chamber 4 (including the spherical gas chamber 4.1 with the largest volume and the spherical gas chamber 4.2 with the smallest volume), and the anti-scouring layer 5 (including the body scouring part 5.1 and the rod head scouring part 5.2). DETAILED DESCRIPTION

[0042] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0043] Example 1

[0044] Combination Figure 1 It can be seen that the present invention discloses a continuous casting argon blowing plug rod, combined with Figure 1It can be seen that it includes a stopper rod body 1 and a stopper rod head 2 located at the front end of the stopper rod body 1, a tubular argon gas channel 3 leading to the stopper rod head 2 is provided in the stopper rod body 1, and the stopper rod head 2 is made of mesoporous material. The apparent porosity of the mesoporous material of the present invention is ≥18%, and the median diameter of the pore size is ≤50nm. It is further preferred that the apparent porosity of the mesoporous material is 18-30%. This is because when the apparent porosity is too large, the density of the stopper rod head is too low and the structure is loose, which affects the use effect; when the apparent porosity is too small, the air permeability is low, which affects the argon blowing effect.

[0045] The stopper head 2 is provided with two or more spherical air chambers 4 connected to the tubular argon gas channel 3 and arranged adjacent to each other in the vertical direction, and the volume of each spherical air chamber 4 gradually decreases from top to bottom. Each spherical air chamber 4 plays a role in buffering the argon gas flow, and the design of each spherical air chamber 4 from large to small is conducive to improving the stability of the argon gas flow entering the stopper head 2. The present invention further preferably has a maximum horizontal length of the spherical air chamber 4.1 with the largest volume not greater than 40% of the length of the stopper head 2 on the same horizontal line, and a maximum horizontal length of the spherical air chamber 4.2 with the smallest volume not less than the diameter of the tubular argon gas channel 3. On the one hand, this design size does not affect the wall diameter of the stopper head and thus ensures the overall strength of the stopper head. On the other hand, it does not affect the anisotropy of the inflowing argon, ensuring that the argon gas is diffusely blown into the molten steel through the mesoporous material in a uniform and stable manner, thereby improving the argon blowing effect. The present invention further preferably has the vertical axes of the spherical air chambers 4 on the same straight line and coincide with the vertical axis of the tubular argon gas channel 3, and the distance between the bottom end of the spherical air chamber 4.2 with the smallest volume and the bottom end of the stopper rod head 2 is 25-40% of the height of the stopper rod head. Figure 1 It can be seen that in this embodiment, two spherical air chambers 4.2 are preferably designed.

[0046] At the same time, the outer wall of the connection between the stopper rod body 1 and the stopper rod head 2 is circumferentially distributed with an anti-scouring layer 5, which is composed of a body scouring portion 5.1 and a rod head scouring portion 5.2. The height of the body scouring portion 5.1 is 30-80 mm, and the height of the rod head scouring portion 5.2 is 30-80% of the height of the stopper rod head 2. When the height of the anti-scouring layer is too high, not only the production cost is high, but also the air permeability and argon blowing effect of the rod head are affected; when the height of the anti-scouring layer is too low, the connection and anti-scouring property between the body and the rod head cannot be effectively enhanced, thereby affecting the argon blowing effect and service life. The thickness of the scouring layer 5 is 25%-40% of the wall thickness of the stopper rod body 1. When the thickness of the anti-scouring layer is too small, the bonding degree with the body and the rod head is poor, the overall anti-scouring property is weak, and the service life is short; when the thickness of the anti-scouring layer is too large, the stability of the stopper rod body and the rod head is affected, and the production cost is increased.

[0047] The volume density of the anti-scour layer 5 and the stopper rod body 1 is ≥3.2 g / cm 3 The preferred weight of the present invention is 3.2 to 3.7 g / cm3 When the volume density of the anti-scour layer 5 is too small, the anti-scour property of the stopper rod portion cannot be improved, which affects the service life; when the volume density is too large, the tightness of the anti-scour layer and the stopper rod body and rod head is affected, and the production cost is too high.

[0048] The present invention also selects and designs the anti-scour layer 5 and reasonably adjusts the material and thickness of the anti-scour layer 5 to further improve the anti-scour property of the stopper rod head 2 and prolong the service life while ensuring that the stopper rod body and the rod head are tightly combined.

[0049] Example 2

[0050] The present invention discloses a method for preparing a stopper rod having the structure of the above-mentioned embodiment 1, which comprises the following steps:

[0051] 1) Ingredients: The various parts of the stopper rod are mixed with various raw materials according to the weight ratio according to the ingredient list;

[0052] The stopper rod head 2 is made of mesoporous material, wherein the mesoporous material is made of the following raw materials in the following weight percentages:

[0053] Sintered corundum 40%-77%, mesoporous corundum 10%-30%, graphite 3%-10%, activated alumina 2%-5%, microporous zirconium aluminum oxide 5%-10%, resin 3%-8%, additional diluent 0.5%-3%, antioxidant 0.3%-3%;

[0054] The anti-scour layer comprises the following raw materials in weight percentage:

[0055] Zirconia corundum 30%-65%, zircon sand 20%-40%, graphite 3%-10%, activated alumina 2%-5%, spinel 5%-10%, resin 3%-8%, antioxidant 0.3%-3%.

[0056] The material of the stopper rod is conventional material in the art.

[0057] 2) Mixing and granulation: put the prepared raw materials into a granulator for mixing and granulation;

[0058] 3) Material trapping: Place the prepared materials in the material trapping room, ensure that the temperature in the trapping room is 20°C, the humidity is less than 40%, and the trapping time is 24h;

[0059] 4) Molding: Add the trapped plug body material, plug head material, and anti-scour layer material into the mold respectively, and mold them in an isostatic pressing device with a molding pressure of 125MPa;

[0060] 5) Drying: Dry the formed plug rod in a drying kiln at 250°C for 18 to 24 hours;

[0061] 6) Firing: Place the stopper rod in a reducing atmosphere firing kiln at 1100°C for 6 hours;

[0062] 7) Machining: Turn the fired stopper rod according to the size requirements of the drawing;

[0063] 8) Coating: evenly coat the outside of the stopper rod with an anti-oxidation coating with a coating thickness of 0.15 to 0.3 mm;

[0064] 9) Flaw detection: Perform X-ray flaw detection on the stopper rod;

[0065] 10) Packaging: Finished products will be packaged after passing the inspection.

[0066] The ingredients of Example 2 and Example 4, Comparative Example 1 and Comparative Example 2 are shown in Table 1 and Table 2, respectively; the preparation process is shown in Table 4; and the properties of the obtained stopper rods are shown in Table 5.

[0067] Table 1 List of raw material compositions of the club heads of various embodiments and comparative examples (Wt, %)

[0068]

[0069]

[0070] Table 2 Raw material composition list of each embodiment and comparative example anti-scour layer (Wt, %)

[0071]

[0072] Table 3 List of main process parameters of each rod head in Table 1

[0073]

[0074] Table 4 Performance list of each club head in Table 3

[0075]

[0076] Table 5 Performance list of each anti-scour layer in Table 2

[0077]

[0078] It can be seen from the above embodiments that the porosity of the stopper rod head designed by the present invention is ≥18%, and the median diameter of the pores is ≤50nm. Under the premise of ensuring the overall strength of the rod head, the stopper rod head allows argon to be diffusely blown into the molten steel to form small and uniform bubbles to eliminate the influence of large bubbles on the crystallizer liquid level fluctuation, and can effectively remove the flocculent inclusions on the rod head, improve the flow control accuracy, enhance the argon blowing effect, and purify the quality of the molten steel. The volume density of the anti-scouring layer designed by the present invention is ≥3.2g / cm 3Its mechanical strength is comparable to that of other parts of the plug head, and it is manufactured using an integrated molding process, which is beneficial to improving the overall firmness.

[0079] The above embodiments are only the best examples, and are not intended to limit the implementation of the present invention. In addition to the above embodiments, the present invention has other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A continuous casting argon blowing plug rod, characterized in that: It comprises a stopper rod body (1) and a stopper rod head (2) located at the front end of the stopper rod body (1), wherein the stopper rod head (2) is made of a mesoporous material; a tubular argon gas passage (3) leading to the stopper rod head (2) is provided inside the stopper rod body (1), and two or more spherical gas chambers (4) connected to the tubular argon gas passage (3) and arranged adjacent to each other in the vertical direction are provided inside the stopper rod head (2), wherein the volume of each spherical gas chamber (4) gradually decreases from top to bottom, and an anti-scouring layer (5) is distributed along the circumferential direction on the outer side wall of the connection between the stopper rod body (1) and the stopper rod head (2); Wherein, the mesoporous material is prepared from the following raw materials in the following weight percentages: Sintered corundum 40%-77%, mesoporous corundum 10%-30%, graphite 3%-10%, activated alumina 2%-5%, microporous zirconium aluminum oxide 5%-10%, resin 3%-8%, additional diluent 0.5%-3%, antioxidant 0.3%-3%; The anti-scour layer comprises the following raw materials in weight percentage: Zirconia corundum 30%-65%, zircon sand 20%-40%, graphite 3%-10%, activated alumina 2%-5%, spinel 5%-10%, resin 5%-8%, antioxidant 0.5%-3%.

2. The continuous casting argon blowing stopper rod according to claim 1, characterized in that: The apparent porosity of the mesoporous material is ≥18%, and the median diameter of the pores is ≤50nm.

3. The continuous casting argon blowing stopper rod according to claim 2, characterized in that: The mesoporous material is prepared from the following raw materials in weight percentage: Sintered corundum 77%, mesoporous corundum 10%, graphite 3%, activated alumina 2%, microporous zirconium aluminum oxide 5%, resin 3%, additional diluent 0.5%, antioxidant 0.3%.

4. The continuous casting argon blowing stopper rod according to claim 1, characterized in that: The volume density of the anti-scour layer (5) and the stopper rod body (1) is ≥3.2 g / cm 3 .

5. The continuous casting argon blowing stopper rod according to claim 4, characterized in that: The anti-scour layer comprises the following raw materials in weight percentage: Zirconia corundum 30%, zircon sand 40%, graphite 10%, activated alumina 5%, spinel 10%, resin 5%, antioxidant 3%.

6. The continuous casting argon blowing stopper rod according to claim 3 or 5, characterized in that: The microporous zirconium aluminum oxide is a microporous zirconium aluminum oxide crystal material; The resin is a liquid thermosetting phenolic resin; The added diluent is one or more alcohol or ketone organic solvents; The antioxidant is one or more of boron carbide, silicon carbide, metal aluminum and metal silicon.

7. The continuous casting argon blowing stopper rod according to claim 1 or 2 or 3 or 4 or 5, characterized in that: The maximum length of the spherical air chamber (4.1) with the largest volume in the horizontal direction is not greater than 40% of the length of the stopper rod head (2) on the same horizontal line, and the maximum length of the spherical air chamber (4.2) with the smallest volume in the horizontal direction is not less than the diameter of the tubular argon gas channel (3); The distance between the bottom end of the spherical air chamber (4.2) with the smallest volume and the bottom end of the stopper rod head (2) is 25-40% of the height of the stopper rod head.

8. The continuous casting argon blowing stopper rod according to claim 7, characterized in that: The vertical axes of the spherical gas chambers (4) are on the same straight line and coincide with the vertical axis of the tubular argon gas channel (3).

9. The continuous casting argon blowing stopper rod according to claim 1 or 2 or 3 or 4 or 5, characterized in that: The anti-scouring layer (5) is composed of a body scouring portion (5.1) and a rod head scouring portion (5.2); the height of the body scouring portion (5.1) is 30 to 80 mm, the height of the rod head scouring portion (5.2) is 30 to 80% of the height of the stopper rod head (2); and the thickness of the anti-scouring layer (5) is 25% to 40% of the wall thickness of the stopper rod body (1).

10. A method for preparing the stopper rod according to claim 1, characterized in that: It includes the following steps: 1) Ingredients: The various parts of the stopper rod are mixed with various raw materials according to the weight ratio according to the ingredient list; 2) Mixing and granulation: put the prepared raw materials into a granulator for mixing and granulation; 3) Material trapping: Place the prepared materials in the material trapping room, ensure that the temperature in the trapping room is 20-25°C, the humidity is less than 40%, and the trapping time is 18-24h; 4) Molding: Add the trapped plug body material, plug head material, and anti-scouring layer material into the mold respectively, and mold them in an isostatic pressing device with a molding pressure of 120-140MPa; 5) Drying: Dry the formed plug rod in a drying kiln at 220-250°C for 18-24 hours; 6) Firing: Place the stopper rod in a reducing atmosphere firing kiln at 1100-1200°C for 5-6 hours; 7) Machining: Turn the fired stopper rod according to the size requirements of the drawing; 8) Coating: evenly coat the outside of the stopper rod with an anti-oxidation coating with a coating thickness of 0.15 to 0.3 mm; 9) Flaw detection: Perform X-ray flaw detection on the stopper rod; 10) Packaging: Finished products will be packaged after passing the inspection.

Images