An antioxidant graphite plug and a method for preparing the same

Abstract

The application provides an antioxidant graphite plug rod and a preparation method thereof. The antioxidant graphite plug rod comprises a plug rod body, a threaded groove is arranged on the surface of the plug rod body, and the surface of the plug rod body is coated with an antioxidant coating; the antioxidant coating comprises a solid component and a solvent; the solid component comprises the following raw materials in mass fraction: 40-60% of ZrO2, 20-40% of Al2O3 and 15-30% of SiO2. The high-temperature antioxidant coating composed of inorganic salts and solvents is coated on the surface of the graphite plug rod, the antioxidant performance of the graphite plug rod can be greatly improved without changing the material of the graphite plug rod, the threaded groove is arranged on the surface of the plug rod body, the friction coefficient of the graphite plug rod is increased, the coating can be effectively prevented from falling off, and the service life of the graphite plug rod is prolonged.

Description

Technical Field

[0001] This invention relates to the field of copper alloy smelting equipment technology, and more specifically, to an antioxidant graphite stopper rod and its preparation method. Background Technology

[0002] Graphite stopper rods are components used in copper alloy smelting to control the flow rate of molten copper during continuous casting, ensuring the stability of the casting process and the quality of the cast billets. Graphite begins to oxidize at 450-500℃, and oxidation occurs rapidly above 1000℃, at a rate 20-50 times faster. Since the temperature of molten copper is generally maintained above 1000℃, the graphite stopper rod undergoes a severe "diameter reduction" phenomenon under the high-temperature oxidation and repeated scouring by the molten copper. When the diameter of the graphite stopper rod is too small, it is prone to breakage during venting. Once broken, the flow rate of the molten copper cannot be controlled, potentially leading to production accidents. Therefore, to ensure production safety and ingot quality, graphite stopper rods with a diameter less than 30mm must be scrapped. Currently, the lifespan of graphite stopper rods used in copper continuous casting is approximately 50-70 hours, while those used in brass have a lifespan of approximately 100-140 hours. Frequent replacement of graphite stopper rods leads to decreased production efficiency and increased manufacturing costs.

[0003] Existing technologies disclose several methods to improve the lifespan of graphite stoppers: one method is to change the composition ratio of the graphite stopper, such as patent CN103332886A which discloses an anti-oxidation integral stopper. In this method, the stopper material is no longer solely graphite; pitch is added as a solvent to improve the adhesive strength of the graphite stopper, and silicon carbide is added to enhance its oxidation resistance, thus increasing the lifespan of the graphite stopper to 480-720 hours. However, pure graphite stoppers are simple to manufacture and easy to machine, while these stoppers with added high-hardness silicon carbide and pitch require high-performance extrusion equipment, and the machining difficulty is significantly increased. Another method is to directly use other materials, such as steel or alloys, to replace graphite. However, these metal stoppers are heavy and easily dissolve at high temperatures, introducing impurities into molten copper. Therefore, these stoppers are only suitable for brass with less stringent requirements and are not suitable for casting copper or bronze alloys. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to improve the service life of graphite stopper rods without changing the material.

[0005] To solve the above-mentioned technical problems, the present invention provides an antioxidant graphite stopper rod, comprising a stopper rod body, the surface of which is provided with threaded grooves, and the surface of which is coated with an antioxidant coating, the antioxidant coating comprising a solid component and a solvent, wherein the solid component comprises the following raw materials in mass fractions: 40-60% ZrO2, 20-40% Al2O3, and 15-30% SiO2.

[0006] This invention coats the surface of a graphite stopper rod with a high-temperature anti-oxidation coating composed of inorganic salts and solvents, which can significantly improve its anti-oxidation performance without changing the material of the graphite stopper rod. In addition, the surface of the stopper rod body is opened with threaded grooves, which increases the friction coefficient of the graphite stopper rod, effectively preventing the coating from falling off and extending the service life of the graphite stopper rod.

[0007] In a preferred or optional embodiment, the solvent for the antioxidant coating is an aqueous solution of aluminum dihydrogen phosphate, wherein the aluminum dihydrogen phosphate accounts for 70-95% by mass. Aluminum dihydrogen phosphate has excellent high-temperature resistance and adhesive strength. The solid component can be dissolved in the aqueous solution of aluminum dihydrogen phosphate. By limiting the proportion of aluminum dihydrogen phosphate in the solvent, the coating becomes a semi-solid state, which is beneficial for adhesion to the stopper rod surface.

[0008] In a preferred or optional embodiment, the mass ratio of solvent to solid component in the antioxidant coating is (1-2):5. This ensures the coating has a certain degree of fluidity, facilitating application and entry into the threaded grooves. Once the coating solidifies together on the stopper rod surface and within the grooves, a coating that is not easily detached is formed.

[0009] In a preferred or optional embodiment, the raw material for the solid component is a solid powder with a particle size of less than 10 μm. Limiting the particle size of the solid component facilitates uniform mixing and ensures that the coating is free of large particles.

[0010] In a preferred or optional embodiment, the coating thickness of the antioxidant coating is 0.5-1.0 mm. The coating needs to have a certain thickness to ensure the antioxidant effect, but it should not be too thick, otherwise it will easily peel off.

[0011] In a preferred or optional embodiment, the diameter of the stopper rod body is 60-100 mm, and the depth of the threaded groove is 1-3 mm. The threaded groove needs to have a certain depth to ensure the adhesion of the coating, but the depth should not exceed 1 / 20 of the diameter of the stopper rod body to ensure the strength of the stopper rod.

[0012] In a preferred or optional embodiment, the width of the threaded groove is 1-2 mm, and the thread pitch is 2-4 cm. The threaded groove needs to be designed with a reasonable width to ensure that the coating inside the groove has sufficient adhesion strength; similarly, if the thread pitch is too wide, the coating adhesion on the surface is small, and if the thread pitch is too narrow, the processing between the threads is difficult, and the graphite is prone to breakage, which will also cause the coating to peel off.

[0013] In a preferred or optional embodiment, the opening direction of the threaded groove is inclined toward the head direction of the stopper rod body, and the angle with the length direction of the stopper rod body is 30-65°. Since the anti-oxidation coating is originally a semi-solid state, the inclined setting of the threaded groove can prevent the coating from peeling off due to gravity.

[0014] Another aspect of the present invention provides a method for preparing the above-mentioned antioxidant graphite stopper rod, comprising the following steps:

[0015] S1. Pre-machining of the stopper rod body: The surface of the stopper rod body is machined with threaded grooves using a lathe.

[0016] S2. Preparation of antioxidant coating: Weigh the solid components of the antioxidant coating, mix them using a ball mill, and then add solvent and stir until uniform;

[0017] S3. Coating: Erect the stopper rod body with threaded grooves in the installation direction, use a brush to apply solvent to the surface of the graphite stopper rod, use another brush to apply anti-oxidation coating to the surface of the stopper rod body, and then apply another coat evenly so that the thickness difference of the coating in different parts does not exceed 0.2mm.

[0018] S4. Drying: Place the graphite stopper rod coated with antioxidant coating into an oven for baking, and cool it down to 50-70℃ with the oven. Store the graphite stopper rod in the oven.

[0019] This invention does not require changing the material of the graphite stopper rod. The graphite stopper rod is easy to machine. First, the threaded groove is machined, then an anti-oxidation coating is applied, and after baking, a coating that fills the groove is formed, which greatly improves the high-temperature oxidation resistance of the graphite stopper rod.

[0020] In a preferred or optional embodiment, step S4 employs gradient heating baking. The first stage involves baking at 100-120°C for 6-10 hours to dry the free water in the solvent. The second stage involves heating to 260-300°C for 2-3 hours to dry the water of crystallization in the solvent. The heating rate in each stage should not exceed 50°C / min to prevent the water seal from failing to precipitate properly due to excessive heating, which could lead to the formation of pores inside the coating and a reduction in its service life.

[0021] In summary, the present invention has the following beneficial effects:

[0022] (1) The present invention does not require changing the material of the graphite stopper rod. The anti-oxidation performance of the stopper rod is improved by structural design and coating with anti-oxidation coating. The service life of the graphite stopper rod of the present invention can reach 800-1000h, thereby improving the production efficiency of copper alloy and reducing manufacturing costs.

[0023] (2) The graphite stopper rod surface is machined with threaded grooves by lathe. The parameters of the threaded grooves are specifically designed to improve the adhesion of the anti-oxidation coating.

[0024] (3) The solid component of the anti-oxidation coating is selected from high melting point inorganic salts, which can form an anti-oxidation layer on the surface of the stopper rod. The solid component is selected from inorganic salts with a coefficient of expansion close to that of graphite, so as to prevent the coating from cracking due to expansion during temperature rise and fall. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the antioxidant graphite stopper rod in a specific embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional view of the antioxidant graphite stopper rod in a specific embodiment of the present invention;

[0027] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle. Attached image description:

[0029] 1-Plug body, 2-Threaded groove. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar symbols and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] This invention provides an antioxidant graphite stopper rod for controlling the flow rate of molten copper during continuous casting. The graphite stopper rod includes a stopper rod body 1, the surface of which is coated with an antioxidant coating. The antioxidant coating improves the antioxidant properties of the graphite stopper rod and extends its service life in high-temperature environments.

[0034] Combination Figure 1 and Figure 2As shown in the figure, the left side is the head of the stopper rod body 1, and the right side is the tail. The stopper rod body 1 is installed with the head facing down. The surface of the stopper rod body 1 is provided with threaded grooves 2 to improve the friction coefficient of the stopper rod body 1, which can effectively prevent the coating formed by the anti-oxidation coating from peeling off.

[0035] Combination Figure 3 As shown, to ensure the anti-detachment effect, the parameters of the threaded groove 2 need to be designed. The diameter of the stopper rod body 1 is generally 60-100mm, and the corresponding depth of the threaded groove 2 should not exceed 1 / 20 of the diameter of the stopper rod body 1 to ensure the original strength of the stopper rod. The depth of the threaded groove 2 should not be too shallow, otherwise the adhesion effect of the coating cannot be guaranteed. Therefore, the depth of the threaded groove 2, h = 1-3mm.

[0036] Similarly, the width of the thread groove 2 should not be too small, otherwise the coating will not be able to enter the groove, and the coating formed in the groove will have limited effect on strengthening the adhesion of the surface coating; the thread groove 2 should not be too wide either, otherwise the adhesion of the coating in the groove will decrease, and the coating will be easy to fall off. Therefore, the width of the thread groove 2 is limited to l = 1.0mm-2.0mm.

[0037] Similarly, if the thread pitch is too wide, the coating on the surface will not adhere well; if the thread pitch is too narrow, the threads will be difficult to process, and the graphite will be prone to breakage, which will also cause the coating to peel off. Therefore, the thread pitch H is limited to 2-4cm.

[0038] Since the anti-oxidation coating is semi-solid when applied, in order to prevent it from peeling off due to gravity, the opening direction of the threaded groove 2 is inclined towards the head of the stopper rod body 1, and the angle with the length direction of the stopper rod body 1 is 30-65°.

[0039] In a specific embodiment, the anti-oxidation coating comprises a solid component and a solvent. The solid component includes the following raw materials by mass fraction: 40-60% ZrO2, 20-40% Al2O3, and 15-30% SiO2. To ensure the anti-oxidation effect and to avoid affecting the molten copper, the solid component in the coating is mainly a high-melting-point inorganic salt. Zirconia and alumina both have melting points above 2000℃. The high-melting-point inorganic salt forms an anti-oxidation layer on the graphite surface, preventing graphite oxidation. Furthermore, the above-mentioned raw materials have a coefficient of thermal expansion close to that of graphite, which can prevent the coating from cracking due to expansion during temperature rises and falls. The addition of silica allows the coating to effectively adhere to the surface of the stopper rod body 1 at high temperatures. However, the amount of silica added should not be too large, otherwise copper oxide may also adhere to the surface and bottom of the stopper rod, and the graphite stopper rod will not be able to stably adhere to the vent hole, affecting the stable control of the molten copper during casting.

[0040] Preferably, the raw materials for the solid components are all solid powders with a particle size of less than 10μm, which facilitates uniform mixing and ensures that there are no large particles remaining in the coating.

[0041] In a specific embodiment, the solvent used in the antioxidant coating is an aqueous solution of aluminum dihydrogen phosphate, wherein the mass percentage of aluminum dihydrogen phosphate is 70-95%. Aluminum dihydrogen phosphate has excellent high-temperature resistance and adhesive strength. The solid component can dissolve in the aqueous solution of aluminum dihydrogen phosphate. By limiting the proportion of aluminum dihydrogen phosphate in the solvent, the coating becomes a semi-solid state, which is beneficial for adhesion to the surface of the stopper rod body 1. Furthermore, the mass ratio of solvent to solid component in the antioxidant coating is (1-2):5. This ensures that the coating has a certain degree of fluidity, which is conducive to brushing and entry into the threaded groove 2. After the coating on the surface and in the groove solidifies together, a coating that is not easy to peel off can be formed.

[0042] Specific embodiments of the present invention also provide a method for preparing the above-mentioned antioxidant graphite stopper rod, comprising the following steps:

[0043] S1. Pre-machining of the stopper rod body: The surface of the stopper rod body 1 is machined with threaded grooves 2 using a lathe. The depth of the threaded grooves 2 is 1-3 mm, the width is 1-2 mm, the thread pitch is 2-4 cm, and the angle of the groove opening with the length direction of the stopper rod body 1 is 30-65°. The purpose of machining the grooves is to increase the coefficient of friction of the stopper rod body 1. At the same time, during the subsequent coating process, some of the coating enters into the grooves and solidifies together with the coating on the surface, which can effectively prevent the coating from peeling off. Once the coating peels off, the graphite stopper rod loses its surface protection and is extremely prone to oxidation.

[0044] S2. Preparation of Antioxidant Coating: Weigh the solid component of the antioxidant coating, which consists of 40-60% ZrO2, 20-40% Al2O3, and 15-30% SiO2. The particle size of the solid powder is less than 10μm. Mix the solid component using a ball mill at a speed of 500-1000 r / min for 8-10 hours. Then, remove the mixture and place it in a container. Add an aqueous solution of aluminum dihydrogen phosphate at a mass fraction of 20-40% of the solid component and stir until homogeneous to obtain a semi-solid coating with no particle residue.

[0045] S3. Coating: Erect the stopper rod body 1 with threaded grooves 2 according to the installation direction. Use a brush to apply an aqueous solution of aluminum dihydrogen phosphate to the surface of the stopper rod to remove excess graphite powder and increase the adhesion of the stopper rod body. Use another brush to apply an anti-oxidation coating to the surface of the stopper rod body 1, allowing part of the composite coating to adhere to the substrate. Then apply another coat evenly, ensuring that the thickness of the coating on the stopper rod surface is 0.5-1.0 mm, and the thickness difference between different parts does not exceed 0.2 mm. The coating thickness should not be too thin, otherwise the anti-oxidation effect cannot be guaranteed. However, excessive thickness or uneven thickness can easily lead to cracking during the heating and cooling process. In addition, if the coating is too thick, the internal and external moisture will not easily dissipate, and the water vapor will cause blistering and rupture during the heating process, thus losing the anti-oxidation effect.

[0046] S4. Drying: Place the graphite stopper rod coated with antioxidant coating into an oven for baking. Use gradient heating for baking. In the first stage, bake at 100-120℃ for 6-10 hours to dry the free water in the solvent. In the second stage, heat to 260-300℃ and bake for 2-3 hours to dry the water of crystallization in the solvent. The heating rate in each stage shall not exceed 50℃ / min. Cool down in the oven to 50-70℃ and store the graphite stopper rod in the oven.

[0047] When using graphite plug rods, they should be installed one hour in advance to allow them to heat up gradually, preventing the coating from cracking due to excessively rapid heating.

[0048] This invention develops a high-temperature anti-oxidation coating composed of various inorganic salts without changing the graphite stopper rod material. By designing threaded grooves on the stopper rod, the coating can be ensured to adhere to the graphite stopper rod, thereby improving the oxidation resistance and service life of the graphite stopper rod, extending its service life to 800-1000 hours. This is of great help in improving the efficiency of copper alloy preparation and reducing costs.

[0049] The technical solution and effects of the present invention will be illustrated below with specific embodiments.

[0050] Example 1

[0051] This embodiment provides an antioxidant graphite stopper rod for copper, and the preparation process is as follows:

[0052] 1) Pre-machining of the stopper rod body: Prepare a stopper rod body with a diameter of φ80mm. The surface is machined with threaded grooves on a lathe. The threaded grooves are 1.5mm deep, 1.5mm wide, and 3cm apart. The groove angle is 45° to the installation direction of the graphite stopper rod.

[0053] 2) Preparation of antioxidant coating: The solid component consists of 50% ZrO2, 30% Al2O3, and 20% SiO2. The solvent is an aqueous solution of aluminum dihydrogen phosphate, of which aluminum dihydrogen phosphate accounts for 95% by mass. The solid powder is weighed according to the proportion and then mixed in a ball mill at 600 r / min for 10 hours. After mixing, it is taken out and placed in a container, and then 30% by mass of aluminum dihydrogen phosphate is added. The mixture is stirred evenly to obtain a semi-solid coating.

[0054] 3) Coating: Stand the machined stopper rod body upright in the installation direction. First, use a brush to apply a portion of aluminum dihydrogen phosphate to the surface of the graphite stopper rod. Then, use another clean brush to apply a small amount of composite coating to the entire stopper rod. Finally, apply another coat evenly. The coating thickness is about 0.8mm.

[0055] 4) Drying: Place the graphite stopper rod coated with antioxidant coating into the oven for gradient heating and baking. In the first stage, bake at 110-120℃ for 10 hours, then raise the temperature to 300℃ for 3 hours, and then cool down to 60℃ in the oven.

[0056] When using this graphite stopper rod, install it one hour in advance to allow it to heat up gradually and prevent the coating from cracking due to excessively rapid heating.

[0057] After 50 hours of direct use of the stopper rod body, the diameter at the smallest position in the stopper rod body was 42 mm; while the graphite stopper rod prepared in this embodiment showed almost no reduction in diameter after 50 hours of use, and its field service life reached 912 hours.

[0058] Example 2

[0059] This embodiment provides an anti-oxidation stopper rod for bronze, and the preparation process is as follows:

[0060] 1) Pre-machining of the stopper rod body: Prepare a stopper rod body with a diameter of φ80mm. The surface is machined with threaded grooves using a lathe. The threaded grooves are 2mm deep, 2mm wide, and 2cm apart. The groove angle is 60° to the installation direction of the graphite stopper rod.

[0061] 2) Preparation of antioxidant coating: The solid component consists of 60% ZrO2, 30% Al2O3, and 10% SiO2. The solvent is an aqueous solution of aluminum dihydrogen phosphate, of which aluminum dihydrogen phosphate accounts for 90% by mass. The solid powder is weighed according to the proportion and then mixed in a ball mill at 600 r / min for 10 hours. After mixing, it is taken out and placed in a container. Then, aluminum dihydrogen phosphate with a mass fraction of 30% of the solid component is added and stirred evenly to obtain a semi-solid coating.

[0062] 3) Coating: Stand the machined stopper rod body upright in the installation direction. First, use a brush to apply a portion of aluminum dihydrogen phosphate to the surface of the graphite stopper rod. Then, use another clean brush to apply a small amount of composite coating to the entire stopper rod. Finally, apply another coat evenly. The thickness of the coating should be about 1.0 mm.

[0063] 4) Drying: Place the graphite stopper rod coated with antioxidant coating into the oven for gradient heating and baking. In the first stage, bake at 110-120℃ for 10 hours, then raise the temperature to 300℃ for 3 hours, and then cool down to 60℃ in the oven.

[0064] When using this graphite stopper rod, install it one hour in advance to allow it to heat up gradually and prevent the coating from cracking due to excessively rapid heating.

[0065] After 50 hours of direct use of the stopper rod body, the diameter of the stopper rod body shrank to 55mm; while the graphite stopper rod prepared in this embodiment did not shrink in diameter after 50 hours of use, and its field service life reached 840 hours.

[0066] Example 3

[0067] This embodiment provides an anti-oxidation stopper rod for brass, and the preparation process is as follows:

[0068] 1) Pre-machining of the stopper rod body: Prepare a stopper rod body with a diameter of φ80mm. The surface is machined with thread grooves using a lathe. The thread groove depth is 1.5mm, the width is 1.2mm, the thread pitch is 3cm, and the groove angle is 45° with the installation direction of the graphite stopper rod.

[0069] 2) Preparation of antioxidant coating: The solid component consists of 40% ZrO2, 40% Al2O3, and 20% SiO2. The solvent is an aqueous solution of aluminum dihydrogen phosphate, of which aluminum dihydrogen phosphate accounts for 75% by mass. The solid powder is weighed according to the proportion and then mixed in a ball mill at 500 r / min for 10 hours. After mixing, it is taken out and placed in a container, and then 30% by mass of aluminum dihydrogen phosphate is added. The mixture is stirred evenly to obtain a semi-solid coating.

[0070] 3) Coating: Stand the machined stopper rod body upright in the installation direction. First, use a brush to apply a portion of aluminum dihydrogen phosphate to the surface of the graphite stopper rod. Then, use another clean brush to apply a small amount of composite coating to the entire stopper rod. Finally, apply another coat evenly. The coating thickness is about 0.8mm.

[0071] 4) Drying: Place the graphite stopper rod coated with antioxidant coating into an oven for gradient heating and baking. The first stage is baking at 110-120℃ for 10 hours, followed by heating to 280℃ for 3 hours, and then cooling down to 60℃ in the oven.

[0072] When using this graphite stopper rod, install it one hour in advance to allow it to heat up gradually and prevent the coating from cracking due to excessively rapid heating.

[0073] After 60 hours of direct use of the stopper rod body, the diameter of the stopper rod body shrank to 60mm; while the graphite stopper rod prepared in this embodiment did not shrink in diameter after 60 hours of use, and its field service life reached 1000 hours.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An antioxidant graphite stopper rod for copper alloy smelting, characterized in that, The device includes a stopper rod body, the surface of which is provided with threaded grooves. The diameter of the stopper rod body is 60-100 mm, the depth of the threaded grooves is 1-3 mm, the width of the threaded grooves is 1-2 mm, and the thread pitch is 2-4 cm. The surface of the stopper rod body is coated with an antioxidant coating, which includes a solid component and a solvent. The solid component includes the following raw materials in mass fractions: 40-60% ZrO2, 20-40% Al2O3, and 15-30% SiO2. The solvent of the antioxidant coating is an aqueous solution of aluminum dihydrogen phosphate, wherein the mass percentage of aluminum dihydrogen phosphate is 70-95%. The mass ratio of the solvent to the solid component in the antioxidant coating is (1-2):

5.

2. The antioxidant graphite stopper rod for copper alloy smelting according to claim 1, characterized in that, The raw material for the solid component is a solid powder with a particle size of less than 10 μm.

3. The antioxidant graphite stopper rod for copper alloy smelting according to claim 1, characterized in that, The coating thickness of the antioxidant coating is 0.5-1.0 mm.

4. The antioxidant graphite stopper rod for copper alloy smelting according to claim 1, characterized in that, The opening direction of the threaded groove is inclined toward the head direction of the stopper body, and the angle with the length direction of the stopper body is 30-65°.

5. A method for preparing an antioxidant graphite stopper rod for copper alloy smelting as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Pre-machining of the stopper rod body: The surface of the stopper rod body is machined with threaded grooves using a lathe. S2. Preparation of antioxidant coating: Weigh the solid components of the antioxidant coating, mix them using a ball mill, and then add solvent and stir until uniform; S3. Coating: Erect the stopper rod body with threaded grooves in the installation direction, use a brush to apply solvent to the surface of the graphite stopper rod, use another brush to apply anti-oxidation coating to the surface of the stopper rod body, and then apply another coat evenly so that the thickness difference of the coating in different parts does not exceed 0.2mm. S4. Drying: Place the graphite stopper rod coated with antioxidant coating into an oven for baking, and cool it down to 50-70℃ with the oven. Store the graphite stopper rod in the oven.

6. The method for preparing the antioxidant graphite stopper rod for copper alloy smelting according to claim 5, characterized in that, In step S4, gradient heating baking is adopted. In the first stage, the temperature is raised to 100-120℃ for 6-10 hours, and in the second stage, the temperature is raised to 260-300℃ for 2-3 hours. The heating rate in each stage does not exceed 50℃ / min.

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