Preparation method of Al-Ti-B grain refiner with high refining efficiency

Abstract

The invention relates to a preparation method of an Al-Ti-B grain refiner with high refining efficiency, the refiner comprises the following main components: 1.0 wt%-10.0 wt% of Ti, 0.1 wt%-3wt% of B, 0.01 wt%-0.5 wt% of Fe, 0.01 wt%-0.3 wt% of Si, 0.001 wt%-0.02 wt% of V and the balance of Al, and the content of vanadium needs to be strictly controlled. The key point of the method is material selection, proportioning and batch charging design, the added materials are divided into three batches to be proportioned according to different components, the materials with the two components need to be fully and uniformly mixed, the titanium material is added as an independent batch according to the proportion, and the temperature and the charging speed are strictly controlled in the preparation process. Generation and dispersion distribution of effective refined particles are achieved, and the prepared refining agent has high refining capacity. When the refiner is applied to wrought aluminum alloy cast ingot or cast rod production and the same grain size is obtained, the addition amount of the refiner is 50% or below of the addition amount of a similar refiner.

Description

Technical Field

[0001] The invention belongs to the technical field of new materials, relates to the manufacture of aluminum alloy materials, and in particular to a method for preparing an Al-Ti-B grain refiner with high refinement efficiency. Background Art

[0002] Grain refinement of aluminum and aluminum alloys refers to adding a small amount of grain refiner to the aluminum and aluminum alloy melt to form heterogeneous crystal nuclei, so that the castings and round ingots and flat ingots used for processing have fine structures, thereby preventing cracks from occurring during casting, facilitating processing deformation, and improving product performance.

[0003] In the 1940s, American scientists Cibula and others conducted extensive research on the refinement of Ti and believed that Al-Ti-B master alloy had the best refinement effect. In the late 1960s, Al-Ti-B alloy wire was born. The appearance of wire reduced the amount of refiner, achieved precise addition, and was conducive to eliminating the segregation of TiB2 in the refiner, and was conducive to automated production. It has now become the main application method.

[0004] Since its development and application, Al-Ti-B grain refiner has been considered an important additive material in the field of aluminum processing, and its quality plays a key role in product processing and performance. On the one hand, this is because the production technology of Al-Ti-B refiner products is difficult and the quality stability is not easy to control; on the other hand, the key refining mechanism has always been controversial. When conducting application tests on refiners, researchers found that the grain refining performance of Al-Ti-B refiners from different manufacturers and different batches varied greatly. Even in the same batch, the refining ability fluctuated greatly, which brought difficulties to the application of refiners and the quality control of aluminum processing products.

[0005] In 2008, MQP, a British company, first proposed the concept of high-refining efficiency Al-Ti-B (OPTIFINE super aluminum titanium boron) through the detection and analysis of a large amount of data on-site at aluminum processing enterprises and the development and verification of the refinement ability evaluation method of the refiner. MQP uses the exclusive Opticast refinement ability evaluation method to accurately and stably detect the refinement efficiency of grain refiners. This method selects samples with good refinement efficiency as standard samples, and its refinement efficiency is 100%. The tested samples are compared with the standard samples. If the refinement efficiency reaches 85%, it meets the standard requirements of high-efficiency refiners or super refiners. On this basis, MQP realized the commercial application of its high-refining efficiency Al-Ti-B (OPTIFINE super aluminum titanium boron) and technology in 2010, which can reduce the addition of Al-Ti-B by more than 70%, bringing significant economic benefits and product quality improvement to customers. Super refiners have been widely used in aluminum processing enterprises at home and abroad. Super refiners and their applications can reduce material addition, save production costs, and are conducive to low carbon and aluminum recycling, which is a milestone in the development of the aluminum industry.

[0006] The advantage of super refiner products lies in their reduced usage and improved refinement efficiency. In order to study its mechanism of action and realize industrial application, Lizhong Sitong New Materials, British MQP Company and Brunel University in London conducted a joint study. By comparing the TiB2 particle structure in the high refinement efficiency of Al-Ti-B and the ordinary refinement capacity, it was found that the refiner with high refinement efficiency contains a high proportion of effective refinement composite particles, that is, TiB2 particles covered with a TiAl3 layer on the surface. This kind of particle is a necessary condition for its refinement nucleation. Therefore, how to maximize the technology of obtaining high-refining capacity composite particles becomes the key.

[0007] The present invention develops a method for obtaining particle generation and dispersion distribution with high refining ability, and develops a production technology and method of a high refining efficiency Al-Ti-B grain refiner through material selection, component ratio, feed design, process design, etc. Summary of the invention

[0008] The purpose of the present invention is to improve the refinement efficiency of Al-Ti-B grain refiner, maximize its refinement ability, reduce the amount of refiner and the negative impact on quality during application, and meet the manufacturing needs of high-performance aluminum alloy materials and components. The present invention is designed by material selection, proportioning, batch feeding and process matching. First, by controlling the introduction of V, an element that is not conducive to grain refinement, into the raw materials, the agglomeration of TiB2 particles is suppressed from the source. Secondly, the present invention controls the material proportion and addition order according to the material properties and in a targeted manner. The titanium-containing material has both potassium fluorotitanate and metallic titanium because the reaction characteristics of the added materials during alloying are different from those of the formed particles. The order of forming microstructures using materials with different proportions and the interdependent conditions between the structures are used to control the generation rate, structure, growth mode and particle size of TiAl3 and TiB2 particles. Specifically, after the first batch of materials are added, an environment rich in Ti and containing a certain amount of TiB2 particles is first formed in the aluminum melt, and then the second batch of materials is added under certain temperature conditions (aluminum ingot temperature control), at which time the mixed materials form TiB2 particles with a specific structure; finally, the third batch of pure Ti material is added, and with further alloying, by controlling the alloying temperature and time, the added Ti combines with the pre-formed TiB2 particles to form multi-component composite particles, that is, a TiAl3 layer is formed on the TiB2 surface. At the same time, by adding sodium fluoroaluminate to the raw materials, the separation of the reaction products can be promoted, and the fluidity and purity of the alloy can be improved. This method solves the problem of low refinement efficiency and poor stability of ordinary Al-Ti-B refiners.

[0009] The technical solution to solve the problem of the present invention is:

[0010] The present invention provides a method for preparing an Al-Ti-B grain refiner with high refinement efficiency, comprising the following steps:

[0011] S1 uses aluminum ingots (basic material), titanium-containing materials and potassium fluoroborate (additive material), sodium fluoroaluminate (additive auxiliary material). Reserve no less than 10% of the total feed amount of aluminum ingots for temperature adjustment.

[0012] Divide the added materials into three batches:

[0013] The Al-Ti-B refiner to be prepared is called the target alloy, and the first batch of materials consists of potassium fluorotitanate, metallic titanium and potassium fluoroborate; the mass of titanium generated by the first batch of potassium fluorotitanate accounts for 10%-30% of the total mass of titanium in the target alloy, the mass of titanium generated by metallic titanium accounts for 0.1-5% of the total mass of titanium in the target alloy, and the mass of boron generated by potassium fluoroborate accounts for 5-30% of the total mass of boron in the target alloy;

[0014] The second batch of materials consists of potassium fluorotitanate, potassium fluoroborate and sodium fluoroaluminate, the mass of titanium generated by the potassium fluorotitanate added in the second batch accounts for 55%-85% of the total mass of titanium in the target alloy, the mass of boron generated by potassium fluoroborate accounts for 70-95% of the total mass of boron in the target alloy, and the mass of sodium fluoroaluminate accounts for 1-20% of the mass of this batch of added materials;

[0015] The third batch of materials is titanium metal, and the mass of titanium generated by the third batch of added titanium metal accounts for 1-10% of the total mass of titanium in the target alloy;

[0016] S2 adds the aluminum ingot into the induction furnace, heats and melts it, degasses it for 5-30 minutes at a temperature of 690-730°C, and then removes the slag;

[0017] S3: Heat the aluminum melt to 680-750℃, add the first batch of materials at a uniform speed once or twice using a feeding car, stir the melt continuously during feeding to ensure sufficient reaction between the added materials and the aluminum liquid, control the feeding time to 5-30min, keep the alloy at 730-900℃ for 10-30min, remove the reaction products or ash; continue to add materials to the alloy melt or transfer the melt to another electric furnace, add cooling aluminum ingots to adjust the aluminum liquid temperature to 680-750℃, add the second batch of materials at a uniform speed once or 2-4 times, stir the melt continuously during feeding, and add each time After the end, the melt is stirred for 5-25min, the alloying temperature is controlled at 730-900℃, the total feeding time is controlled at 20-90min, and after the feeding is completed, the alloying is kept at 750-950℃ for 10-60min, the reaction product or ash is removed, and the remaining cooling ingots (if any) are added; continue to feed or transfer to another electric furnace. The third batch of materials is pure titanium material, the melt is in the converter or in the original furnace, the feeding temperature is controlled at 780-850℃, the material is added evenly, the time is controlled at 5-30min, the alloying time is 10-30min, and the temperature is controlled between 780-950℃.

[0018] S4 slag removal: after the reaction is completed, clean the salt solution or surface oxides, and control the temperature at 750-1000℃;

[0019] S5 melt refining, the temperature is controlled in the range of 750-1000℃, the alloy melt is refined for 10-60min, and slag is removed during refining;

[0020] S6 casting and continuous casting and rolling, clean the slag on the surface of the melt, control the casting temperature at 760-1000℃, cast into ingots or roll into wires.

[0021] Furthermore, the three batches of materials are added in sequence. Each time the materials are added, they need to be fully stirred, with no accumulation of materials on the surface as the standard.

[0022] Furthermore, the V content in the aluminum ingot and the additive material is controlled below 0.02%, and the V content in the product is 0.001-0.02%.

[0023] Furthermore, the metallic titanium is titanium powder or titanium block with a purity greater than 98wt%.

[0024] Further, after adding the first batch of materials, alloying is performed at 830-850° C. for 10-30 min.

[0025] Furthermore, the temperature is controlled at 680-720°C before adding the second batch of materials, and is adjusted by adding a cooling ingot.

[0026] Further, after adding the second batch of materials, alloying is carried out at 780-820° C. for 20-40 min.

[0027] Further, after adding the third batch of materials, alloying is performed at 790-820° C. for 10-20 min.

[0028] Furthermore, the casting temperature is controlled at 800-850°C.

[0029] The key to the present invention lies in the selection of materials, preparation ratio and batch feeding design, as well as matching process control, including preparing potassium fluorotitanate, metallic titanium, potassium fluoroborate and sodium fluoroaluminate that meet the standards (mainly V < 0.02wt%) in batches in proportion and mixing them evenly. The purpose of controlling V is mainly to inhibit the aggregation of effective particles during and after formation, which is conducive to dispersed distribution. The additive material is divided into three batches, two of which are mixtures of titanium-containing materials and potassium fluoroborate, and one batch is pure titanium material. The purpose of this design is to match different materials with processes, and form a small amount of TiB2 particles with smaller size in the early stage, and a small amount of Ti in the melt, which has an initial melt environment. With the addition of further additive materials, the newly generated particles can be well combined with the particles formed in the early stage to form a large number of TiB2 particles that meet certain size and structural requirements. Finally, the added Ti is coated on the surface of TiB2 to promote the formation of composite particles, and these particles will become the key to refinement; sodium fluoroaluminate is mixed into the material, and its role is to facilitate the separation of reaction products and aluminum during the alloying reaction, improve purity and fluidity, and facilitate uniform distribution of particles and stable product quality. The present invention focuses on the generation and uniform dispersion of effective refined particles in the Al-Ti-B refiner through raw material selection, ratio design, mixing, feeding sequence design, and process control. The typical grades of refiners mainly include AlTi3B1, AlTi5B1, AlTi5B0.2, etc.

[0030] The present invention uses aluminum as a matrix material, potassium fluorotitanate, pure titanium material, potassium fluoroborate and sodium fluoroaluminate as additive materials to prepare an alloy material. According to the material properties and the formation structure characteristics, in the first stage, materials are added, mainly potassium fluorotitanate, and a small amount of potassium fluoroborate is added to form a melt environment mainly composed of Ti and having certain Ti and B components, and a small amount of TiB2 particles will be formed; then in the second stage, materials are added, a mixture of potassium fluorotitanate, potassium fluoroborate and sodium fluoroaluminate is added, the starting temperature of the reaction is controlled, and on the basis of the original melt environment, a part of the composite is generated by reacting with the newly added material. Particles and TiB2 particles with good interface and structure, at this time, through sufficient reaction and alloying, and then using the purification effect of sodium fluoroaluminate, the separation of reaction products and slag inclusions is promoted to form a clean melt and dispersed distribution of TiAl3 and TiB2 particles; in the third stage, the remaining pure titanium material is added, alloyed at a certain temperature, and the remaining pure titanium is added at the same time. These titaniums will quickly dissolve and combine with the TiB2 particles generated in the melt to form a large number of effective composite particles, that is, TiB2 particles covered with TiAl3 layers, thereby improving the product's refinement ability. In addition, the V content is controlled in the present invention mainly because V will generate TiBV compounds during the alloying process, which promotes the aggregation of TiB2, resulting in uneven organization and affecting the refinement stability.

[0031] Advantages and beneficial effects of the present invention:

[0032] The present invention controls the V content of the raw materials according to the product characteristics of the Al-Ti-B grain refiner through material composition control, material ratio, feeding sequence design and process matching, and realizes the generation of high-efficiency refined particles and the production of high-efficiency refiner by designing different feeding ratios and alloying processes through material and process control. The method is simple, the process is short, and industrial production is easy to realize.

[0033] The high-refining-efficiency Al-Ti-B grain refiner can be manufactured in batches and stably by using the present invention, and has uniform composition and structure and strong refining ability.

[0034] The Al-Ti-B refiner manufactured using this invention has been widely verified and applied. Currently, more than 5 million tons of aluminum are manufactured annually worldwide using this refiner, saving more than 50% of the refiner usage, saving manufacturing costs, transportation and storage costs, and saving use costs, meeting the manufacturing needs of high-performance aluminum alloy materials and components, and contributing to the low-carbon and sustainable development of the aluminum industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a flow chart of the preparation method of the present invention;

[0036] Figure 2 This is a photo of the AlTi3B1 product manufactured in Example 1;

[0037] Figure 3 This is a microstructure photo of AlTi3B1 manufactured in Example 1;

[0038] Figure 4 High-resolution transmission electron microscopy photos of the composite particles in AlTi3B1 prepared in Example 1, wherein (a) is a basal plane image of TiB2 particles observed by electron microscopy, and (b) is an atomic arrangement image of TiB2 and the surface Al3Ti 2DC layer;

[0039] Figure 5 This is a photo of the AlTi3B1 refinement produced in Example 1 (TP-1 method);

[0040] Figure 6 This is a comparison chart of the refining ability of AlTi3B1 manufactured in Example 1 and a common refiner in AA1050 aluminum alloy;

[0041] Figure 7 This is a comparison chart of the refining ability of AlTi3B1 manufactured in Example 1 and common refining agent in 6061 aluminum alloy casting rod;

[0042] Figure 8 Microstructure photo of AlTi3B1 manufactured in Comparative Example 2;

[0043] Fig. 9 This is a microstructure photograph of AlTi5B1 manufactured in Example 2;

[0044] Fig.10 This is the energy spectrum analysis photograph of TiB2 aggregation containing V in AlTi5B1 produced in Comparative Example 3. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0046] Example 1: Production of AlTi3B1 grain refiner with high refining efficiency

[0047] The V content in the aluminum ingot is 0.012wt%, and the V content in other materials is less than 0.01wt%.

[0048] According to the composition of AlTi3B1 alloy and the output of 1100kg of finished products, the amount of aluminum used is 1050kg, and titanium and boron are mixed according to the theoretical content of Ti3.05 wt% (33.55kg) and B1.02 wt% (11.22kgB, equivalent to 129kg potassium fluoroborate). 200kg of aluminum ingots are reserved for cooling.

[0049] The raw materials are divided into three batches. The first batch of materials contains 37.5 kg of potassium fluorotitanate (accounting for about 22.3% of the total mass of titanium in the alloy), 0.5 kg of metallic titanium (accounting for about 1.5% of the total mass of titanium in the alloy), and 10 kg of potassium fluoroborate (accounting for about 7.7% of the total mass of boron in the alloy); the second batch of materials contains 120 kg of potassium fluorotitanate (accounting for about 71.5% of the total mass of titanium in the alloy), 119 kg of potassium fluoroborate (accounting for about 92.3% of the total mass of boron in the alloy), and 10 kg of sodium fluoroaluminate (accounting for about 3.3% of the weight of this batch of materials). The third batch of materials contains 1.6 kg of titanium powder (accounting for about 4.7% of the total titanium content in the alloy).

[0050] Mix the first batch and the second batch of materials evenly and load them into the material cart. Use tools to add the third batch of materials evenly.

[0051] Weigh 900kg aluminum ingot, add it into the induction furnace for melting, degas for 8-10min at a temperature of 720-730℃, and then remove slag;

[0052] Adjust the aluminum melt temperature to 700-705℃, add the first batch of materials at a uniform speed in 2 times using a feeding car, stir the melt continuously during feeding, control the full reaction between the materials and the aluminum melt, control the feeding time to 5-8min, keep the alloy at 830-840℃ for 10-15min, remove the reaction products or ash; continue to feed the alloy melt, add the second batch of materials at a uniform speed in 2 times, stir the melt continuously during feeding, add aluminum ingots before feeding or adjust the aluminum melt temperature to 690-700℃, and finish each feeding. After the bundle is bundled, the melt is stirred for 10-15 minutes, the temperature is controlled at less than 900°C, the total feeding time is controlled at 25-30 minutes, and after the feeding is completed, the alloying is kept at 790-800°C for 30-40 minutes, the reaction product or ash is removed, and the remaining cooling ingots (if any) are added; the melt is transferred to another electric furnace, the third batch of materials is pure titanium material, the feeding temperature is controlled at 780-790°C, it is added evenly, the time is controlled at 5-7 minutes, the alloying temperature is 810-815°C, and the time is 18-20 minutes.

[0053] After the reaction is finished, remove the slag, clean the salt solution or surface oxides, and control the temperature at 800-810℃;

[0054] Melt refining: adjust the temperature in the range of 800-810℃, refine the alloy melt for 25-30min, and remove slag while refining;

[0055] Casting and continuous casting and rolling, clean the slag on the surface of the melt, control the casting temperature at 810-815℃, cast into ingots or roll into wires.

[0056] The hollow rolls manufactured in Example 1 are as follows Figure 2 .

[0057] The product manufactured in Example 1 was analyzed. It can be seen from Table 1 that the composition of AlTi3B1 manufactured in Example 1 is close to the theoretical value, the V content is 0.012wt%, and the microstructure is as follows: Figure 3 , it can be seen that TiAl3 and TiB2 are evenly distributed.

[0058] In order to verify the structure and mechanism of the refiner, a high-resolution transmission electron microscope was used to analyze the TiB2 particles in the refiner. Figure 4 As can be seen from a and b, a TiAl3 layer is formed on the surface of the TiB2 particles, and a large number of effectively refined particles exist in the structure.

[0059] The refinement ability test of the refiner is divided into refinement effect and refinement efficiency. The refinement effect usually adopts the internationally common TP-1 refinement ability test method, which can evaluate the refinement ability of the refiner to a certain extent; the other is the Optcast grain refiner evaluation method developed and used by the British MQP company to evaluate the refinement efficiency of the grain refiner. In conventional refinement inspection, the main process of the TP-1 grain refinement standard test method includes: adding 0.2% Al-Ti-B alloy to 99.7wt% pure aluminum melt, keeping it at 720-730℃ for 2min, casting it into a standard conical specimen, cooling the specimen mold by circulating water cooling, and then using the line intercept method to detect the grain morphology and grain size of the cross section of a specific part of the specimen. Generally, the standard for high-efficiency grain refiners requires that the average grain size should be less than 120μm. Optcast grain refiner evaluation method uses its special mold to test standard samples and samples to be tested at the same time. Refiner is added to 99.7wt% aluminum liquid, slowly cooled, and grain test is performed on the fixed position of the sample. It is compared with the standard sample and the refinement efficiency is calculated. Generally, a refinement efficiency greater than 85% is considered to be an efficient grain refiner.

[0060] Figure 5 This is a photo of the refinement results. From the figure, we can see that the grain structure is equiaxed grains, the average grain size is 115μm, and the refinement efficiency is 98%, which meets the standard requirements of high-efficiency refiners.

[0061] Figure 6 This is a comparison chart of the grain sizes of AlTi3B1 manufactured in Example 1 and ordinary refiners in 1050 aluminum alloy as the addition amount changes. The ordinary refiner needs to be added at 0.5kg / t to reach a grain size of 180 microns, while the addition amount of the super refiner (manufactured in Example 1) is less than 0.2kg / t. Overall, to obtain the same grain size, the amount of refiner manufactured in Example 1 is less than half of that of the ordinary refiner.

[0062] In addition, the effects of superfine agents and ordinary fine agents were verified in large-scale production. Figure 7As shown, the target alloy is 6061 aluminum alloy cast rod with a diameter of 420mm. Five melting comparison experiments were carried out, with the addition amount of ordinary refiner being 2kg / t and the addition amount of super refiner being 1kg / t. It can be seen that to achieve the same grain size, the amount of super refiner is less than 50% of that of ordinary refiner.

[0063] Comparative Example 1: Production of AlTi3B1 Grain Refiner

[0064] The difference from Example 1 is that the raw materials are the same, the feed amount is the same, the theoretical ratio of the materials is the same, and the difference is that there are only two batches of materials, the third batch of materials is mixed into the second batch of materials, and the feeding and alloying parameters remain the same as in Example 1.

[0065] The raw materials are divided into two batches. The first batch of materials includes 37.5 kg of potassium fluorotitanate (accounting for about 22.3% of the total mass of titanium in the alloy), 0.5 kg of metallic titanium (accounting for about 1.5% of the total mass of titanium in the alloy), and 10 kg of potassium fluoroborate (accounting for about 7.7% of the total mass of boron in the alloy); the second batch of materials includes 120 kg of potassium fluorotitanate (accounting for about 71.5% of the total mass of titanium in the alloy), 119 kg of potassium fluoroborate (accounting for about 92.3% of the total mass of boron in the alloy), 10 kg of sodium fluoroaluminate (accounting for about 3.3% of the weight of this batch of materials), and 1.6 kg of titanium powder (accounting for about 4.7% of the total titanium content in the alloy).

[0066] The product manufactured in Comparative Example 1 was analyzed. It can be seen from Table 1 that the composition of Comparative Example 1 is not much different from that of Example 1. However, the grain refining effect of AlTi3B1 manufactured in Comparative Example 1 is 135 microns, and the refining efficiency is 70%, which does not meet the requirements of a high-efficiency refiner.

[0067] Comparative Example 2: Production of AlTi3B1 Grain Refiner

[0068] The difference from Example 1 is that sodium fluoroaluminate is not added to the second batch of materials, and other material proportions, process conditions and operations are the same.

[0069] The product manufactured in Comparative Example 2 was analyzed. It can be seen from Table 1 that the composition of Comparative Example 2 is close to the theoretical value, the refinement effect is 123 microns, and the refinement efficiency is 80%, which is worse than that of Example 1. At the same time, there are TiB2 aggregations and mixed aggregations in the microstructure, such as Figure 8 As shown, this is mainly related to the separation of reaction products and the deterioration of fluidity.

[0070] Example 2: Production of AlTi5B1 grain refiner with high refining efficiency

[0071] The V content in the aluminum ingot is less than 0.02wt%, and the V content in other materials is less than 0.01wt%.

[0072] According to the composition of AlTi5B1 and the output of 1100kg of finished products, the amount of aluminum used is 1030kg, and titanium and boron are mixed according to the theoretical content of Ti5.05wt% (55.55kg) and B1.02wt% (1.22kgB, equivalent to 129kg potassium fluoroborate). 200kg of aluminum ingots are reserved as cooling aluminum ingots for temperature adjustment.

[0073] The raw materials are divided into three batches. The first batch of materials includes 80 kg of potassium fluorotitanate (accounting for about 28.8% of the total mass of titanium in the alloy), 1 kg of metallic titanium (accounting for about 1.8% of the total mass of titanium in the alloy), and 10 kg of potassium fluoroborate (accounting for about 7.7% of the total mass of boron in the alloy); the second batch of materials includes 178 kg of potassium fluorotitanate (accounting for about 64% of the total mass of titanium in the alloy), 119 kg of potassium fluoroborate (accounting for about 92.3% of the total mass of boron in the alloy), and 15 kg of sodium fluoroaluminate (accounting for about 3.7% of the weight of this batch of materials). The third batch of materials includes 3 kg of titanium powder (accounting for about 5.4% of the total titanium content in the alloy).

[0074] Mix the first batch and the second batch of materials evenly and load them into the material cart. Use tools to add the third batch of materials evenly.

[0075] Weigh 900kg aluminum ingot, add it into the induction furnace for melting, degas for 8-10min at a temperature of 720-730℃, and then remove slag;

[0076] Heat the aluminum melt to 690-700℃, add the first batch of materials at a uniform speed in two times using a feeding car, stir the melt continuously during feeding, control the full reaction between the materials and the aluminum liquid, control the feeding time to 13-15min, keep the alloy at 830-850℃ for 25-30min, remove the reaction products or ash; transfer the alloy melt to another electric furnace or continue to feed, add aluminum ingots or adjust the aluminum liquid temperature to 690-700℃, add the second batch of materials at a uniform speed to the alloy melt, stir the melt continuously during feeding, add aluminum ingots or adjust the temperature before feeding. The temperature of the aluminum liquid reaches 690-700℃. After each feeding, the melt is stirred for 8-10min and the temperature is controlled at 770-800℃. The total feeding time is controlled at 35-40min. After the feeding is completed, alloying is carried out at 800-810℃ for 30-35min, the reaction products or ash are removed, and the remaining cooling ingots (if any) are added; the melt is transferred to another electric furnace. The third batch of materials is pure titanium material. The feeding temperature is controlled at 800-810℃ and added evenly. The time is controlled at 8-9min and the alloying time is 10-12min.

[0077] After the reaction is finished, remove the slag, clean the salt solution or surface oxides, and control the temperature at 800-900℃;

[0078] Melt refining, the temperature is adjusted in the range of 810-820℃, the alloy melt is refined for 20-25min, and slag is removed during refining;

[0079] Casting and continuous casting and rolling, clean the slag on the surface of the melt, control the casting temperature at 840-850℃, cast into ingots or roll into wires.

[0080] The product manufactured in Example 2 is analyzed. It can be seen from Table 1 that the composition of AlTi5B1 manufactured in Example 2 is close to the theoretical value, and the V content is 0.012wt%. After the refinement test, the refinement ability is 110 microns and the refinement efficiency is 105%, which meets the standard requirements of the super refiner.

[0081] Fig. 9 This is a microstructure photograph of AlTi5B1 manufactured in Example 2. It can be seen from the figure that TiAl3 and TiB2 are evenly distributed.

[0082] Comparative Example 3: Production of AlTi5B1 Grain Refiner

[0083] The difference from Example 2 is that the V content of the aluminum ingot is greater than 0.02wt%, and other conditions remain unchanged.

[0084] The product manufactured in Comparative Example 3 was analyzed. From the composition, Ti and B components are close to the theoretical content, while the V content reaches about 0.035wt%. The grains are refined to 125 microns, and the refinement efficiency is 75%. The SEM analysis shows that Fig.10 Obvious TiB2 aggregation was observed in the product, and energy spectrum analysis showed that V was contained in it. It can be seen that the increase in V content intensified the aggregation of TiB2 particles, and it was inferred that the refinement ability was affected.

[0085] Comparative Example 4: Production of AlTi5B1 grain refiner

[0086] The difference from Example 2 is that no aluminum ingot is reserved for cooling, and no cooling aluminum ingot is added for temperature adjustment and control before adding the second batch of materials, and other conditions remain unchanged.

[0087] The product manufactured in Comparative Example 4 was analyzed. From Table 1, it can be seen that the Ti and B components are close to the theoretical content, the grain size is refined to 129 microns, and the refining efficiency is 70%, which is worse than that in Example 2 and does not meet the requirements of an efficient refiner.

[0088] Table 1 Composition and refining ability of refiners

[0089]

[0090] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept, which all belong to the protection scope of the present invention.

Claims

1. A method for preparing an Al-Ti-B grain refiner with high refining efficiency, characterized in that: The following steps are involved: S1 selects aluminum ingots and additive materials, wherein the additive materials include titanium-containing materials, potassium fluoroborate and sodium fluoroaluminate, and the titanium-containing materials include potassium fluorotitanate and metallic titanium, and reserves aluminum ingots of not less than 10% by weight of the total feed amount as cooling aluminum ingots; Divide the added materials into three batches: The Al-Ti-B refiner to be prepared is called a target alloy, and the first batch of materials consists of potassium fluorotitanate, metallic titanium, and potassium fluoroborate; the mass of titanium generated by the potassium fluorotitanate added in the first batch accounts for 10%-30% of the total mass of titanium in the target alloy, the mass of titanium generated by the metallic titanium accounts for 0.1-5% of the total mass of titanium in the target alloy, and the mass of boron generated by the potassium fluoroborate accounts for 5-30% of the total mass of boron in the target alloy; The second batch of materials consists of potassium fluorotitanate, potassium fluoroborate and sodium fluoroaluminate. The mass of titanium generated by the potassium fluorotitanate added in the second batch accounts for 55%-85% of the total mass of titanium in the target alloy, the mass of boron generated by potassium fluoroborate accounts for 70%-95% of the total mass of boron in the target alloy, and the mass of sodium fluoroaluminate accounts for 1-20% of the mass of this batch of added materials. The third batch of materials is titanium metal, and the mass of titanium generated by the third batch of added titanium metal accounts for 1-10% of the total mass of titanium in the target alloy; S2 adds the aluminum ingot into the induction furnace, heats and melts it, degassing it for 5-30 minutes at a temperature of 690-730℃, and then removes the slag; S3: Heat the aluminum melt to 680-750℃, add the first batch of materials at a uniform speed once or twice using a feeding car, and stir the melt continuously during feeding to ensure that the added materials react fully with the aluminum liquid. The feeding time is controlled at 5-30min, and alloying is carried out at 730-900℃ for 10-30min, and the reaction products or ash are removed; continue to add materials to the alloy melt or transfer the melt to another electric furnace, add cooled aluminum ingots to adjust the melt temperature to 680-750℃, and add the second batch of added materials to the alloy melt at a uniform speed once or 2-4 times, and stir the melt continuously during feeding to ensure that the added materials react fully with the aluminum liquid. Melt in time, stir the melt for 5-25 minutes after each addition, control the alloying temperature at 730-900℃, and control the total addition time at 20-90 minutes. After the addition is completed, alloy and keep warm at 750-950℃ for 10-60 minutes, remove the reaction products or ash, and add the remaining cooling ingots (if any); continue to add materials in the original furnace or transfer to another electric furnace; the third batch of materials is pure titanium material, the feeding temperature is controlled at 780-850℃, added evenly, the time is controlled at 5-30 minutes, the alloying time is 10-30 minutes, and the temperature is controlled between 780-950℃; S4 slag removal: after the reaction is completed, clean the salt solution or surface oxides, and control the temperature at 750-1000℃; S5 melt refining, controlling the temperature in the range of 750-1000℃, refining the melt for 10-60min, and removing slag during melt refining; S6 casting and continuous casting and rolling, cleaning the slag on the surface of the melt, controlling the casting temperature at 760-1000°C, casting into ingots or rolling into wires, the obtained aluminum titanium boron grain refiner contains 1.0wt%-10.0wt% Ti, 0.1wt%-3wt% B, 0.01wt%-0.5wt% Fe, 0.01wt%-0.3wt% Si, 0.001wt%-0.02wt% V, and the balance Al.

2. The preparation method according to claim 1, characterized in that The V content in the aluminum ingot and the added materials is controlled below 0.02%, and the V content in the product is 0.001-0.02%.

3. The method according to claim 1, characterized in that The metallic titanium is titanium powder or titanium block with a purity greater than 98 wt%.

4. The preparation method according to claim 1, characterized in that Each time you add material, you need to stir it thoroughly so that the added salt can dissolve in time and there is no salt accumulation on the surface.

5. The preparation method according to claim 1, characterized in that After adding the first batch of materials, alloying is carried out at 830-850℃ for 10-30min.

6. The preparation method according to claim 1, characterized in that The temperature was controlled at 680-720°C before adding the second batch of materials and was adjusted by adding cooling ingots.

7. The preparation method according to claim 1, characterized in that After adding the second batch of materials, alloying was carried out at 780-820°C for 20-40 minutes.

8. The preparation method according to claim 1, characterized in that After adding the third batch of materials, alloying was carried out at 790-820°C for 10-20 minutes.

9. The preparation method according to claim 1, characterized in that The casting temperature is controlled at 800-850℃.

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