Method for interface reaction modification of Al2O3 and Ce-containing molten steel in refractory and product

Abstract

The invention relates to a method for interface reaction modification of Al2O3 and Ce-containing molten steel in a refractory and a product. The method comprises the steps of raw material melting, electrode device connection, pulse current treatment and sampling air cooling. The device is simple in structure and method, low in cost and high in efficiency, an innovative thought for regulating and controlling an interface between Al2O3 in the refractory and molten steel to inhibit erosion reaction between rare earth elements and the refractory is provided, sample surface characterization is conducted on an original state, pulse current treatment and non-pulse current treatment through XRD, results can powerfully prove that the device has a remarkable effect, and the method is suitable for popularization and application. And a new solution is provided for inhibiting nozzle nodulation in the Ce-containing casting process.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical continuous casting, and specifically relates to a method and a product for modifying the interface reaction between Al2O3 in refractory materials and Ce-containing molten steel. Background Art

[0002] Rare earth metals are widely used in steel smelting due to their unique physical and chemical properties. Adding rare earth elements to molten steel can effectively purify the molten steel, modify inclusions, micro-alloy and refine grains. The deep drawing performance, corrosion resistance, wear resistance, drawing performance and other properties of the final product steel will be greatly improved. Therefore, it can replace the same type of steel at a lower cost and maximize profits.

[0003] Although rare earth steel has many advantages, in production, especially during continuous casting, the casting of rare earth steel is often interrupted due to blockage of the water nozzle during the casting process, resulting in low output of finished steel and a certain degree of resource waste.

[0004] Taking Ce-containing steel as an example, nozzle blockage is mainly caused by the contact between molten steel and refractory materials during continuous casting, which causes the graphite in the refractory materials to be dissolved by the molten steel. After losing the protection of graphite, Al2O3 in the refractory materials directly contacts with molten steel. Active elements in the molten steel, such as Ce, directly react with Al2O3 to produce rare earth aluminates, such as CeAlO3 and CeAlO3. 11 O 18 The high melting point inclusions in the molten steel, such as CaS and rare earth oxides, are deposited on the inner wall of the nozzle. Then, the high melting point inclusions in the molten steel, such as CaS and rare earth oxides, are attached to this as a base. As the surface morphology of the interface between the molten steel and the refractory material changes, turbulence is generated when the molten steel flows through this area, which accelerates the transfer of high melting point inclusions from the molten steel to the interface, and so on. The casting environment is sharply deteriorated, and finally the continuous casting is completely interrupted.

[0005] In the prior art, the nozzle blockage problem is mainly solved by blowing Ar, improving the cleanliness of the molten steel in the tundish, changing the nozzle structure, and changing the interface wettability. For example, the prior art (CN114716850B) and (CN115849920B) use a special coating on the nozzle surface to avoid direct contact between the molten steel and the refractory material, and the coating is not easy to react with La and Ce in the molten steel, which can inhibit the nozzle nodulation during the casting of rare earth steel. However, the nozzle coating preparation process is cumbersome, which increases time and labor costs, and the actual effect is not significant.

[0006] Traditional methods for suppressing nozzle blockage have long processes, complex processes, and limited anti-blocking capabilities. However, with the development of electromagnetic metallurgical technology, electric pulses, as a green and convenient means, have become a new hot research direction for suppressing nozzle blockage.

[0007] The prior art (CN112658241B) forms a double electric layer by applying an interfacial electric field, inhibits decarburization at the water nozzle, and reduces the degree of reaction between the refractory and the rare earth steel liquid, thereby improving the blockage of the water nozzle. However, in actual production, the flow field of the molten steel is complex, and it is impossible to form a stable double electric layer electric field on the entire contact surface between the molten steel and the refractory, and there is a great threshold for practical application. The prior art (CN111906266B) produces liquid compounds with refractory and rare earth metals by applying a pulsed electric field. The liquid compound acts as an intermediate layer to avoid direct contact between the refractory and the molten steel, inhibits the corrosion of the refractory by the molten steel, ensures the integrity of the overall structure of the water nozzle and the smoothness of the interface, thereby improving the blockage of the water nozzle. The pulsed electric field is applied on both sides of the refractory to regulate the reaction between the rare earth oxide and the refractory oxide to generate a multi-element liquid phase. However, in the casting process of the molten steel, in addition to the rare earth oxide, there are also molten rare earth elements in the molten steel, and the reaction priority cannot be guaranteed. If the rare earth elements react with the refractory before the rare earth oxides, the blockage of the water nozzle cannot be effectively improved. Therefore, there is an urgent need to provide a new processing method. Summary of the invention

[0008] In order to overcome the problems existing in the prior art, the present invention provides a method and product for modifying the interface reaction between Al2O3 in refractory and Ce-containing molten steel, which is used to solve the problem that the nozzle coating measures to inhibit nozzle blockage are relatively complicated and the effect of inhibiting the adhesion of inclusions is limited. The pulse current method currently used to inhibit nozzle blockage has a certain effect on aluminum-killed steel, sulfur-containing steel and other steels, but in rare earth steel casting, especially high rare earth steel casting, the effect cannot achieve the expected problem.

[0009] A method for modifying the interface reaction between Al2O3 in a refractory and a Ce-containing molten steel, the method comprising the following steps:

[0010] S1. The Ce-containing rare earth steel is placed in a crucible, and the crucible is heated in a pit furnace until the Ce-containing rare earth steel is completely melted, and kept warm for a certain period of time;

[0011] S2. Connect the wire in the electrode device to the nickel-based chuck and the pulse power supply, fix the two electrodes with two nickel-based chucks respectively, connect the end of one of the electrodes to the nozzle refractory rod, and then preheat the two electrodes;

[0012] S3. inserting the two preheated electrodes into the molten steel containing Ce, applying a pulse current to the two electrodes to modify the surface of the refractory Al2O3;

[0013] S4. After the pulse current treatment is completed, the two electrodes are taken out from the Ce-containing molten steel and air-cooled. After cooling to room temperature, the one electrode is separated from the refractory rod of the water nozzle to obtain a refractory material with Al2O3 modified on the refractory surface.

[0014] According to the above aspects and any possible implementation, there is further provided an implementation, wherein the Ce content in the molten steel in step S1 is in the range of 1-1000 ppm.

[0015] According to the aspects described above and any possible implementation method, an implementation method is further provided, wherein the materials of the two electrodes are pure iron electrodes or graphite electrodes, the refractory material is Al-C refractory material, and the shape of the nozzle refractory rod is rod-shaped or cylindrical.

[0016] According to the aspects described above and any possible implementation, there is further provided an implementation, wherein the nozzle refractory rod is connected to one of the electrodes by means of threads.

[0017] According to the above aspects and any possible implementation, an implementation is further provided, wherein when the Ce content in the molten steel is [1,100] ppm, the pulse frequency is set at 500 Hz or above, and the pulse current is set at 50 A or above.

[0018] According to the above aspects and any possible implementation, an implementation is further provided, when the Ce content in the molten steel is (100, 200] ppm, the pulse frequency is set at 5000 Hz or above, and the pulse current is set at 70 A or above.

[0019] According to the above aspects and any possible implementation, an implementation is further provided, when the Ce content in the molten steel is (200, 300] ppm, the pulse frequency is set at 10000 Hz or above, and the pulse current is set at 100 A or above.

[0020] According to the above aspects and any possible implementation, an implementation is further provided, when the Ce content in the molten steel is (300, 400] ppm, the pulse frequency is set at 20000 Hz and above, and the pulse current is set at 150 A and above.

[0021] According to the aspects described above and any possible implementation method, an implementation method is further provided, whereby when the Ce content in the molten steel is higher than 400 ppm, the pulse frequency is set at 40000 Hz or higher, and the pulse current is set at 200 A or higher.

[0022] The present invention also provides a refractory material, which is obtained by using the method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a method for controlling the modification of Al2O3 in refractory materials in Ce-containing molten steel by using pulse current, which can effectively inhibit the direct reaction between rare earth elements and refractory materials. Under the action of pulse current, Si elements in the molten steel and refractory materials react with refractory Al2O3 in priority to active metal elements such as Ce in the molten steel, first generating 3Al2O3·SiO2, and then Si reacts with the 3Al2O3·SiO2 phase to generate a low-melting-point liquid phase around the refractory Al2O3, thereby avoiding the contact reaction between Ce in the molten steel and the refractory Al2O3 to generate a high-melting-point phase structure at the interface; at the same time, the low-melting-point liquid phase inhibits the attachment of high-melting-point inclusions in the molten steel, such as CaS, rare earth oxides, etc., due to its low wettability. The present invention adopts pulse parameters of different frequencies according to the different Ce contents in the molten steel to ensure that the 3Al2O3·SiO2 layer has a certain thickness. When the thickness of the structure reaches 40μm or more, a sufficient number of low-melting-point phases can be generated. In addition, this method has a simple process and is easy to operate. Compared with traditional direct current, pulse current is greener and more energy-efficient, which is conducive to industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of an electrode device of the present invention;

[0026] Figure 2 This is an interface SEM-EDS image of controlling the modification of Al2O3 in refractory during continuous casting of Ce-containing steel using pulse current according to Example 1 of the present invention;

[0027] Figure 3 This is a reaction mechanism diagram of controlling the modification of Al2O3 in refractory during continuous casting of Ce-containing steel using pulse current according to Example 1 of the present invention;

[0028] Figure 4 The XRD phase structure diagrams of the original refractory material, Example 1 of the present invention, and Comparative Example 2 samples. DETAILED DESCRIPTION

[0029] In order to better understand the technical solution of the present invention, the content of the present invention includes but is not limited to the specific implementation methods described below, and similar technologies and methods should be considered to be within the scope of protection of the present invention. In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] It should be clear that the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0032] A method for modifying the interface reaction between Al2O3 in a refractory and a Ce-containing molten steel, the method comprising the following steps:

[0033] S1. The Ce-containing rare earth steel is placed in a crucible 3, and the crucible 3 is heated in a pit furnace 4 until the Ce-containing rare earth steel is completely melted, and kept warm for a certain period of time;

[0034] S2. Connect the wire 5 in the electrode device to the nickel-based chuck 1 and the pulse power supply 9, fix the two electrodes 2 with the two nickel-based chucks 1 respectively, connect the end of one of the electrodes to the nozzle refractory rod 8 made of Al-C nozzle refractory, and then preheat the two electrodes to reduce the temperature difference between the two when the refractory is inserted into the molten steel; the electrode device specifically includes a nickel-based chuck 1, a wire 5 and two electrodes 2, the end of one of the electrodes is connected to the nozzle refractory rod 8 through a thread, and the nickel-based chuck 1 and the wire 5, and the nickel-based chuck 1 and the electrode 2 are all fixed by bolts. Figure 1 The pit furnace 4 and the crucible 3 are the heating carriers of the device. The experimental temperature of the device is about 1550°C. The pit furnace 4 needs to be used for heating and the crucible 3 needs to be used for holding molten steel.

[0035] S3. Insert the two preheated electrodes into the crucible 3 of the molten Ce-containing steel liquid 7. The Al-C refractory material can conduct electricity at high temperatures. One electrode is inserted into the Ce-containing steel liquid, and the other electrode is connected to the water inlet refractory rod 8. The refractory part is inserted into the steel liquid. After power is turned on, the current density on the surface of the refractory material is relatively large, which can ensure the stable progress of the Al2O3 modification reaction on the surface of the refractory material. The current loop in the device is: power supply-electrode-molten steel-refractory-electrode-power supply. Pulse current is applied to the two electrodes for treatment. At the interface between the molten steel and the refractory surface, specifically on the surface of the refractory rod at the water inlet, the Si element in the molten steel and the refractory reacts with the refractory Al2O3 before active metal elements such as Ce in the molten steel, first generating 3Al2O3·SiO2, and then Si reacts with the 3Al2O3·SiO2 phase to generate a low-melting-point liquid phase around the refractory Al2O3, thereby avoiding the direct contact reaction between Ce in the molten steel and the refractory Al2O3 to generate a high-melting-point cerium aluminate structure at the interface; at the same time, the low-melting-point liquid phase inhibits the adhesion of high-melting-point inclusions in the molten steel, such as CaS, rare earth oxides, etc., due to its low wettability, thereby achieving Al2O3 modification on the refractory surface to inhibit the adhesion of inclusions;

[0036] S4. After the pulse current treatment is completed, the two electrodes are taken out from the Ce-containing molten steel and air-cooled. After cooling to room temperature, the one electrode is separated from the nozzle refractory rod, and a refractory material with Al2O3 modified on the surface of the nozzle refractory rod is obtained.

[0037] The present invention controls the interface reaction so that Si reacts with Al2O3 before Ce to generate an intermediate phase, thereby fundamentally inhibiting the generation of rare earth inclusions at the interface.

[0038] Preferably, according to the existing rare earth steel production situation, the Ce content of the molten steel in step S1 is in the range of 1-1000 ppm.

[0039] Preferably, the electrode material in step S2 includes but is not limited to pure iron electrode, graphite electrode, etc., and the refractory material is Al-C refractory material, which is modified with Al2O3.

[0040] Preferably, in step S2, the connection between the refractory material and the electrode includes but is not limited to various contact connections such as threaded connection 6 to facilitate current conduction.

[0041] Preferably, in steps S1 and S3, when the Ce content in the molten steel is different, the pulse parameters to achieve the modification of Al2O3 are also set differently, as follows:

[0042] When the Ce content in the molten steel is [1,100] ppm, the pulse frequency is 500 Hz or above, and the pulse current is 50 A or above, a 3Al2O3·SiO2 layer with a thickness of 40 μm or above can be stably generated to inhibit the adhesion of inclusions;

[0043] When the Ce content in the molten steel is (100,200]ppm, the pulse current frequency is 5000Hz or above, and the pulse current is 70A or above, a 3Al2O3·SiO2 layer with a thickness of 40μm or above can be stably generated to inhibit the adhesion of inclusions;

[0044] When the Ce content in the molten steel is (200,300]ppm, the pulse current frequency is 10000Hz or above, and the pulse current is 100A or above, a 3Al2O3·SiO2 layer with a thickness of 40μm or above can be stably generated to inhibit the adhesion of inclusions;

[0045] When the Ce content in the molten steel is (300,400]ppm, the pulse frequency is 20000Hz or above, and the pulse current is 150A or above, a 3Al2O3·SiO2 layer with a thickness of 40μm or above can be stably generated to inhibit the adhesion of inclusions;

[0046] When the Ce content in the molten steel is higher than 400ppm, the pulse current frequency is 40000Hz or above, and the pulse current is 200A or above, a 3Al2O3·SiO2 layer with a thickness of 40μm or above can be stably generated to inhibit the adhesion of inclusions.

[0047] As an embodiment disclosed in the present invention, the present invention also provides a refractory material, which is obtained by the described method. The material has the function of inhibiting the erosion of Ce-containing molten steel, ensuring the smoothness of the refractory surface, having low wettability with molten steel, and effectively preventing the adhesion of high-melting-point inclusions.

[0048] The method of the present invention will be described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0049] Example 1

[0050] S1. Raw material melting

[0051] 1000g of rare earth steel with a Ce content of about 300ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0052] S2. Electrode device connection

[0053] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0054] S3, Pulse current processing

[0055] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current with a parameter of 20000Hz-150A is applied for treatment;

[0056] S4, Sampling air cooling

[0057] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0058] After taking out, XRD detection was performed on the sample surface, which proved that there were no rare earth inclusions on the surface. SEM detection showed that the thickness of the 3Al2O3·SiO2 layer was about 50μm. Figure 2 The transient dissolution process of Al2O3-3Al2O3·SiO2-liquid phase is shown, which is the composition change of Al2O3 particles at the interface during the denaturation process after the reaction, which is Al2O3-3Al2O3·SiO2-liquid phase, Figure 3The schematic diagram of the reaction mechanism shows that under the action of pulse current, Al2O3 in the refractory reacts with the molten steel and Si in the refractory itself to generate an intermediate phase material 3Al2O3·SiO2 of a certain thickness. Subsequently, Si further reacts with the intermediate phase to generate a liquid phase. Elements such as Ce in the molten steel are dissolved in the liquid phase in the form of solutes, and the modification is completed.

[0059] Example 2

[0060] S1. Raw material melting

[0061] 1000g of rare earth steel with a Ce content of about 300ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0062] S2. Electrode device connection

[0063] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0064] S3, Pulse current processing

[0065] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current with a parameter of 30000Hz-150A is applied for treatment;

[0066] S4, Sampling air cooling

[0067] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0068] After taking out, XRD detection was performed on the sample surface, which proved that there were no rare earth inclusions on the surface. SEM detection showed that the thickness of the 3Al2O3·SiO2 layer was about 70μm.

[0069] Example 3

[0070] S1. Raw material melting

[0071] 1000g of rare earth steel with a Ce content of about 450ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0072] S2. Electrode device connection

[0073] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0074] S3, Pulse current processing

[0075] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current of 30000Hz-250A is applied for treatment;

[0076] S4, Sampling air cooling

[0077] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0078] After taking out, XRD detection was performed on the sample surface, which proved that there were no rare earth inclusions on the surface. SEM detection showed that the thickness of the 3Al2O3·SiO2 layer was about 67μm.

[0079] Example 4

[0080] S1. Raw material melting

[0081] 1000g of rare earth steel with a Ce content of about 150ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0082] S2. Electrode device connection

[0083] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0084] S3, Pulse current processing

[0085] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current of 7000Hz-90A is applied for treatment;

[0086] S4, Sampling air cooling

[0087] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0088] After taking out, XRD detection was performed on the sample surface, which proved that there were no rare earth inclusions on the surface. SEM detection showed that the thickness of the 3Al2O3·SiO2 layer was about 53μm.

[0089] Comparative Example 1

[0090] 1000g of rare earth steel with a Ce content of about 300ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0091] S2. Electrode device connection

[0092] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0093] S3, pulse current processing

[0094] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current with a parameter of 200Hz-30A is applied for treatment;

[0095] S4, Sampling air cooling

[0096] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0097] After taking out, the liquid phase on the sample surface did not completely cover the refractory material. XRD detection was performed and rare earth inclusions were generated on the surface. SEM detection did not find 3Al2O3·SiO2 layer. This is because at this rare earth content, the pulse parameters are not sufficient to generate enough 3Al2O3·SiO2 layer and then generate liquid phase to inhibit the reaction between rare earth and refractory material.

[0098] Comparative Example 2

[0099] 1000g of rare earth steel with a Ce content of about 300ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0100] S2. Electrode device connection

[0101] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0102] Then the two were inserted into the molten steel without applying pulse current. After the same time of heat preservation, no liquid phase was generated on the surface of the refractory material, and dark green material was attached to the surface. Through XRD detection, Figure 4 As shown, the substance is cerium aluminate.

[0103] Comparative Example 3

[0104] S1. Raw material melting

[0105] 1000g of rare earth steel with a Ce content of about 150ppm was placed in a crucible, heated in a pit furnace until it was completely molten, and kept warm for 10 minutes to make the internal temperature and composition uniform;

[0106] S2. Electrode device connection

[0107] Connect the nickel-based chuck with a wire, fix two graphite electrodes with the nickel-based chuck, connect the Al-C nozzle refractory rod to the end of one of the electrodes, and then preheat both of them;

[0108] S3, pulse current processing

[0109] After S2 is prepared, the two electrodes are preheated and inserted into the Ce-containing steel liquid in S1, and a pulse current of 2000Hz-30A is applied for treatment;

[0110] S4, Sampling air cooling

[0111] After the S3 pulse current treatment is completed, the electrode is taken out from the molten steel and air-cooled. After cooling to room temperature, the electrode is separated from the refractory material to obtain a refractory material with surface modified by Al2O3.

[0112] After the sample was taken out, dark green material adhered to the surface. XRD detection of the sample surface proved that there was cerium aluminate on the surface. SEM detection showed that no 3Al2O3·SiO2 layer was generated.

[0113] like Figure 4 As shown, the original refractory material is composed of C, Al2O3, ZrO2, and SiO2. The refractory material is placed in a steel liquid containing Ce, and no pulse current is applied. In addition to the unreacted refractory material itself, a new phase of cerium aluminate is generated on the surface. When the refractory material is placed in a steel liquid containing Ce, after a pulse current is applied, there is only a 3Al2O3·SiO2 structure on the surface, indicating that the method of the present invention can effectively inhibit the reaction of Ce with the refractory material and the attachment of high melting point inclusions. By comparing the embodiment with the comparative example, it can be seen that different parameters of pulse currents are required for different rare earth contents, otherwise the successful modification of Al2O3 cannot be achieved.

[0114] In summary, the device structure and method of the present invention are simple, low cost, high efficiency, and adopt an innovative idea of ​​controlling the Al2O3 denaturation pathway in the refractory to inhibit the reaction between rare earth and refractory. The surface characterization of the original state, pulse current treatment, and non-pulse current treatment samples by XRD can effectively prove the significant effect of the present invention, such as Figure 4 As shown. This provides a new solution to inhibit nozzle blockage during Ce-containing casting.

[0115] The above description shows and describes several preferred embodiments of the present invention, but as mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not depart from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for modifying the interface reaction between Al2O3 in refractory and molten steel containing Ce, characterized in that: The method comprises the following steps: S1. The Ce-containing rare earth steel is placed in a crucible, and the crucible is heated in a pit furnace until the Ce-containing rare earth steel is completely melted, and kept warm for a certain period of time; S2. Connect the wire in the electrode device to the nickel-based chuck and the pulse power supply, fix the two electrodes with two nickel-based chucks respectively, connect the end of one of the electrodes to the nozzle refractory rod, and then preheat the two electrodes; S3. inserting the two preheated electrodes into the molten steel containing Ce, applying a pulse current to the two electrodes to modify the surface of the refractory Al2O3; S4. After the pulse current treatment is completed, the two electrodes are taken out from the Ce-containing molten steel and air-cooled. After cooling to room temperature, the one electrode is separated from the refractory rod of the water nozzle to obtain a refractory material with Al2O3 modified on the refractory surface.

2. The method according to claim 1, characterized in that The Ce content in the molten steel in step S1 is in the range of 1-1000 ppm.

3. The method according to claim 1, characterized in that The two electrodes are made of pure iron electrodes or graphite electrodes, and the refractory material of the nozzle refractory rod is Al-C, and the shape is rod-shaped or cylindrical.

4. The method according to claim 1, characterized in that: The nozzle refractory rod is connected to one of the electrodes by threading.

5. The method according to claim 2, characterized in that: When the Ce content in the molten steel is [1,100] ppm, the pulse frequency is set at 500 Hz or above, and the pulse current is set at 50 A or above.

6. The method according to claim 2, characterized in that When the Ce content in the molten steel is (100,200]ppm, the pulse frequency is set at 5000Hz or above, and the pulse current is set at 70A or above.

7. The method according to claim 2, characterized in that When the Ce content in the molten steel is (200,300]ppm, the pulse frequency is set at 10000Hz or above, and the current is set at 100A or above.

8. The method according to claim 2, characterized in that: When the Ce content in the molten steel is (300,400]ppm, the pulse frequency is set at 20000Hz or above, and the pulse current is set at 150A or above.

9. The method according to claim 2, characterized in that: When the Ce content in the molten steel is higher than 400ppm, the pulse frequency is set at 40000Hz or above, and the pulse current is set at 200A or above.

10. A refractory material, characterized in that: The refractory material is obtained by the method according to any one of claims 1 to 9.

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