Aluminum-titanium-boron wire intermediate alloy smelting production process

Abstract

The application provides a new smelting production process of aluminum-titanium-boron wire intermediate alloy, relates to the technical field of aluminum alloy material preparation, and solves the technical problem that the addition of other substances in the existing aluminum-titanium-boron wire production process introduces new impurities into the alloy, which weakens the refining effect.The application comprises the following steps: pure aluminum, potassium fluoborate and potassium fluotitanate are weighed respectively, and part of the potassium fluotitanate is mixed with all the potassium fluoborate to obtain a mixture; an aluminum ingot is melted to obtain aluminum liquid, and the mixture is first added into the aluminum liquid, then the remaining potassium fluotitanate is added, and stirring is continuously performed; the stirring reaction is performed for 20-40 min, and the reduction reaction is completed.The application adopts the method that the mixture is first configured and then the fluorsalt is added in batches and at intervals, thereby effectively improving the TiB2 content in the aluminum-titanium-boron wire intermediate alloy, reducing the impurity content, and improving the refining effect.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy material preparation technology, and more specifically, to a process for smelting an aluminum-titanium-boron wire master alloy. Background Technology

[0002] Aluminum-titanium-boron (ATiB) wire master alloy is a commonly used grain refiner in the production of aluminum and aluminum alloys. Adding ATiB wire master alloy during the production of master aluminum alloys can refine the base material, resulting in well-refined grains in the castings and more stable product quality. Currently, the industrial production of ATiB wire mainly uses the fluoride salt method, which involves a chemical reaction between a mixed salt of potassium fluorotitanate and potassium fluoroborate and liquid aluminum. The fluoride salt method for preparing ATiB wire master alloy mainly involves the following reactions:

[0003] 6KBF4+3K2TiF6+10Al=3TiB2 +9KAlF4+K3AlF6 (1)

[0004] 3K2 TiF6+13Al=3TiAl3+ 3KAlF4+ K3AlF6 (2)

[0005] 2KBF4+3Al= AlB2+ 2KAIF4 (3)

[0006] The Al-Ti-B system mainly contains TiB2 and TiAl3 particles. The TiAl3 particles dissolve after being added, increasing the content of dissolved titanium in the melt. The key TiB2 exists in the form of particles, and the smaller its diameter, the stronger its ability to refine the grains of aluminum or aluminum alloys.

[0007] Existing technologies typically employ rare earth doping methods to improve the morphology and size of TiAl3 and TiB2 particles in aluminum-titanium-boron alloys, thereby addressing the issue of TiB2 particle aggregation. For example, Chinese patent CN112011704A describes how adding rare earth oxides or rare earth fluorides improves the size, morphology, and distribution of TiAl3 and TiB2 particles in a grain refiner, resulting in a grain refiner with higher refining performance.

[0008] For example, the patent with publication number CN115305376A proposes an aluminum-titanium-boron wire with a strong grain refining effect and its preparation method. By adding a certain amount of vanadium and potassium to the aluminum-titanium-boron wire, the surface properties of TiB2 particles are effectively improved, thereby obtaining a grain refiner with higher refining performance.

[0009] Another method for preparing an aluminum-titanium-boron wire grain refiner is proposed in patent CN104561619A. First, potassium chloride is added to the aluminum liquid and melted to cover the surface of the aluminum liquid. Then, potassium fluoroborate is added to the aluminum liquid and mixed evenly. Then, potassium fluorotitanate is added to the aluminum liquid. After heating and stirring to complete the reaction, an alloy aluminum liquid is obtained. This method avoids the aluminum liquid from being oxidized or absorbing gas, which would cause porosity or looseness, and improves the elongation of the aluminum-titanium-boron wire.

[0010] However, the above preparation methods, which add rare earth oxides or rare earth fluorides, vanadium, potassium and potassium chloride to improve particle morphology and size, have the additives carried into the aluminum melt to form metal salts or impurities, which are difficult to remove effectively and completely from the aluminum-titanium-boron alloy. In actual operation, these impurities are easily carried into the refined alloy along with the refining agent, weakening the refining effect of the aluminum alloy.

[0011] In the preparation method of an aluminum-titanium-boron wire grain refiner proposed in patent CN104561619A, potassium fluoroborate is added to the aluminum melt and mixed evenly, and then potassium fluorotitanate is added to the aluminum melt. In the preparation of Al-Ti-B master alloy, although the chemical reactions that occur in sequence are different, only TiAl3 and TiB2 are ultimately generated. However, when KBF4 is added first and then K2TiF4, AlB2 is generated in addition to TiAl and TiB2. Due to the generation of AlB2, the amount of TiB2 that can actually be used for grain refinement in the alloy is reduced. Generally speaking, the nucleation ability of AlB2 is very poor. Therefore, the grain refinement ability of Al-Ti-B master alloy with this phase composition will be significantly reduced. Summary of the Invention

[0012] This invention provides a process for smelting an intermediate alloy for aluminum-titanium-boron wire, which solves the technical problem that adding other substances to the existing aluminum-titanium-boron wire production process introduces new impurities into the system, which are then carried into the alloy refining process, thus weakening the refining effect.

[0013] The embodiments of the present invention are achieved through the following technical solutions:

[0014] A process for smelting an aluminum-titanium-boron wire master alloy includes the following steps:

[0015] S1: Raw material selection: Weigh out pure aluminum, potassium fluoroborate and potassium fluorotitanate respectively, and mix part of potassium fluorotitanate with all of potassium fluoroborate to obtain a mixture;

[0016] S2: Aluminum melting and batching: Melt aluminum ingots to obtain molten aluminum, add the mixed material to the molten aluminum at intervals, then add the remaining potassium fluorotitanate, and continue stirring;

[0017] S3: Reduction reaction: Stir the reaction for 20-40 minutes. After the reduction reaction is complete, first pour out the salt produced, and then pour out the aluminum-titanium-boron intermediate alloy into an ingot.

[0018] S4: Slag Refining: The aluminum-titanium-boron intermediate alloy ingot obtained in S3 is melted again and slag refined by adding aluminum alloy slag remover.

[0019] S5: Stirring and degassing: After slag removal and refining, the aluminum liquid is conditioned and stirred again to remove gas, slag, and purify.

[0020] S6: Rolling and forming: After degassing and slag removal, the molten aluminum is guided through the flow channel into the continuous casting production line, stirred, and rolled into aluminum-titanium-boron rods.

[0021] Using this technical solution, a portion of potassium fluorotitanate and all of potassium fluoroborate are mixed in a certain proportion and added to the aluminum liquid to react. The aluminum liquid is in sufficient quantity relative to the potassium fluoroborate and potassium fluorotitanate. Reactions (1), (2) and (3) occur simultaneously in the reaction system. For reaction (1), the amount of potassium fluoroborate is in excess relative to the amount of potassium fluorotitanate. Therefore, the conversion rate of potassium fluorotitanate in the equilibrium state of reaction (1) is higher than that of potassium fluoroborate, which effectively improves the conversion rate of potassium fluorotitanate. The remaining potassium fluoroborate and potassium fluorotitanate react in reactions (3) and (2) respectively to generate AlB2 and TiAl3 respectively.

[0022] Then, the remaining potassium fluorotitanate was added under stirring. At this time, the potassium fluorotitanate was in excess and the aluminum liquid was not sufficient. Because the requirement of the amount of aluminum liquid for reaction (1) is relatively low compared with that for reactions (2) and (3), under the limitation of aluminum liquid, reaction (1) is mainly promoted, the degree of reaction (1) is increased, and the TiB2 content is increased. Reactions (2) and (3) are slightly affected. Because the potassium fluorotitanate is in excess, the degree of reaction (2) is higher than that of reaction (3), and the amount of TiAl3 generated is higher than that of AlB2. From the thermodynamic calculation and analysis, in the high-temperature Al-Ti-B melt, the stability of AlB2 is lower than that of TiB2. When Ti is present, AlB2 will transform into TiB2, as shown in reaction (4).

[0023] TiAl3(s)+AlB2(s)=TiB2(s)+4Al(1) (4)

[0024] Therefore, when the TiAl3 content is higher than that of AlB2, the AlB2 conversion rate can be improved, the AlB2 content can be reduced, and the TiB2 content can be effectively increased at the same time.

[0025] In the two processes above, the first process of adding the mixture is in the absence of potassium fluorotitanate. The conversion rate of potassium fluorotitanate in reaction (1) is high, but the content of TiB2 is low. At the same time, it can prevent the TiB2 content from being too high and agglomerating in the early stage. By adding potassium fluorotitanate in the later stage, the reactions (2) and (3) are promoted. The reaction degree of reaction (2) is too high due to the excess of potassium fluorotitanate, which in turn increases the AlB2 conversion rate in reaction (4) and effectively reduces the AlB2 content. The AlB2 generated in reaction (3) is converted into TiB2, which increases the TiB2 content. The TiB2 obtained in the later stage is uniformly distributed in the system because it is obtained from AlB2 through the conversion in reaction (4) and is not easy to agglomerate. The intermediate alloy with increased TiB2 content and reduced AlB2 content is obtained, which can effectively improve the alloy refinement effect.

[0026] Preferably, in step S1, pure aluminum, potassium fluoroborate, and potassium fluorotitanate are weighed out according to a mass ratio of pure aluminum, potassium fluoroborate, and potassium fluorotitanate within the range of 1:0.24 to 0.27:0.1 to 0.12; wherein the aluminum content of the pure aluminum is >99.70%.

[0027] Using this technical solution, potassium fluorotitanate is in overall excess for reaction (1), ensuring a high TiB2 content in the subsequent reaction.

[0028] Preferably, in step S1, the mass ratio of potassium fluoroborate and a portion of potassium fluorotitanate in the mixture is 2.4 to 2.8:1.

[0029] Using this technical solution, the potassium fluoroborate in the mixture is sufficient for reaction (1), ensuring that the conversion rate of potassium fluorotitanate increases when the mixture is added to the reaction.

[0030] Preferably, in step S2, when the temperature of the molten aluminum reaches 700-800°C, the mixture and the remaining potassium fluorotitanate are added sequentially at 3-5 minute intervals according to the mass ratio weighed in step S1.

[0031] Using this technical solution, the temperature of the aluminum liquid meets the reaction requirements and also meets the reaction conditions required for the thermodynamic forward direction of reaction (4).

[0032] Preferably, in step S3, the temperature change is detected every 5 minutes during the stirring process, and the reaction is continued for 20 to 40 minutes.

[0033] Using this technical solution, temperature changes are detected in order to control the temperature to meet the conversion conditions of reaction (4).

[0034] Preferably, in step S4, the temperature of the molten aluminum needs to be maintained at 720-760°C during the slag removal process.

[0035] Using this technical solution, the aluminum ingots are remelted by slag removal, ensuring uniform melting and sequential slag removal.

[0036] Preferably, in step S5, the temperature of the degassing and slag removal process is controlled at 740–780°C.

[0037] This technical solution utilizes a secondary slag removal process to increase the temperature, facilitating complete slag removal and purification.

[0038] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0039] 1. The addition of fluoride salt in this invention is divided into two processes. The first process is to add the mixture to improve the conversion rate of potassium fluorotitanate and prevent the TiB2 content from being too high and agglomerating in the early stage. Then, potassium fluorotitanate is added to promote the reactions (2), (3) and (4) and increase the TiB2 content.

[0040] 2. In this invention, reaction (4) has a high AlB2 conversion rate, which effectively reduces the AlB2 content. The AlB2 generated in reaction (3) is converted into TiB2. The TiB2 obtained subsequently is obtained from AlB2 through the conversion in reaction (4). It is evenly distributed in the system and is not easy to agglomerate. The intermediate alloy with increased TiB2 content and reduced AlB2 content is obtained, which can effectively improve the alloy refinement effect. Detailed Implementation

[0041] The pure aluminum used in the following examples and comparative examples is national standard pure aluminum with an aluminum content greater than 99.70%, and the potassium fluorotitanate and potassium fluoroborate are common chemically pure reagents with a purity ≥ 99.5%.

[0042] Example 1

[0043] A new process for smelting and producing an aluminum-titanium-boron wire master alloy includes the following steps:

[0044] 1) Raw material selection: Weigh out pure aluminum, potassium fluoroborate and potassium fluorotitanate according to the mass ratio of 1:0.24:0.12, and take 500 kg, 120 kg and 60 kg respectively. Take all 120 kg of potassium fluoroborate and 46 kg of potassium fluorotitanate to prepare a mixture, and keep the remaining 14 kg of potassium fluorotitanate separately.

[0045] 2) Melting aluminum and batching: Melt aluminum ingots in a medium frequency furnace. When the temperature reaches 750℃, pour the mixture into a ladle. Add the mixture and the remaining potassium fluorotitanate into the molten aluminum in two separate batches according to the ratio. Stir continuously for 20 to 40 minutes.

[0046] 3) Reduction reaction: Stirring is carried out as needed in the reduction reaction; the temperature change is monitored every 5 minutes during the stirring process, and the reaction is continued for 30 minutes. After the reduction reaction is completed, the salt produced in the reaction process is poured out first, and then the aluminum-titanium-boron intermediate alloy is poured out and cast into ingots for easy reintroduction into the medium frequency furnace.

[0047] 4) Slag removal and refining: The aluminum-titanium-boron intermediate alloy ingot is melted again in the medium frequency furnace. During the alloying process, the temperature of the aluminum liquid needs to be maintained at about 740℃. An aluminum alloy slag remover is added for slag removal, followed by degassing and refining.

[0048] 5) Stirring and degassing: After slag removal, the refined aluminum-titanium-boron master alloy is put into the holding furnace. The temperature is controlled at about 760℃ for stirring, degassing, slag removal and purification, so that the aluminum-titanium-boron master alloy is uniformly purified.

[0049] 6) Rolling: After the aluminum-titanium-boron intermediate alloy liquid is uniformly purified, fused and stabilized, the aluminum liquid is guided through the flow channel into the continuous casting production line, where it is stirred again and rolled into aluminum-titanium-boron rods.

[0050] Example 2

[0051] The only difference between this embodiment and Embodiment 1 is the selection of raw materials: pure aluminum, potassium fluoroborate, and potassium fluorotitanate are weighed according to a mass ratio of 1:0.24:0.1, and 500 kg, 120 kg, and 50 kg are taken respectively. All 120 kg of potassium fluoroborate and 46 kg of potassium fluorotitanate are used to prepare a mixture, and the remaining 4 kg of potassium fluorotitanate is reserved separately.

[0052] Example 3

[0053] The only difference between this embodiment and Embodiment 1 is the selection of raw materials: pure aluminum, potassium fluoroborate, and potassium fluorotitanate are weighed according to a mass ratio of 1:0.27:0.12, with 500 kg, 135 kg, and 60 kg of each respectively. All 135 kg of potassium fluoroborate and 52 kg of potassium fluorotitanate are used to prepare a mixture, and the remaining 8 kg of potassium fluorotitanate is reserved separately.

[0054] Example 4

[0055] The only difference between this embodiment and Embodiment 1 is the selection of raw materials: pure aluminum, potassium fluoroborate, and potassium fluorotitanate are weighed according to a mass ratio of 1:0.27:0.1, with 500 kg, 135 kg, and 50 kg of each respectively. All 135 kg of potassium fluoroborate and 48 kg of potassium fluorotitanate are used to prepare a mixture, and the remaining 2 kg of potassium fluorotitanate is reserved separately.

[0056] Comparative Example 1

[0057] The only difference between this embodiment and Embodiment 1 is the selection of raw materials: pure aluminum, potassium fluoroborate, and potassium fluorotitanate are weighed according to a mass ratio of 1:0.24:0.12, with 500 kg, 120 kg, and 60 kg respectively. During aluminum melting and batching, all 60 kg of potassium fluorotitanate and potassium fluoroborate are added to the molten aluminum.

[0058] Specifically, the material addition ratios and related data for Examples 1-4 and Comparative Example 1 are shown in Table 1:

[0059] Table 1. Material addition ratios and related data for Examples 1-4 and Comparative Example 1

[0060]

[0061]

[0062] As shown in the table above, Examples 1-4 represent different technical solutions for the present application when the total amount of potassium fluoroborate and potassium fluorotitanate is prepared with different proportions and the mixture is prepared with different proportions. The comparative example is the technical solution under the original process. It can be seen that compared with the comparative example, the technical solution of the present application first prepares a mixture of potassium fluoroborate and potassium fluorotitanate and then adds it to the remaining potassium fluorotitanate in turn, dividing the reaction process into two stages. In the first stage, reaction (1) is the main reaction to improve the conversion rate of potassium fluorotitanate. In the second stage, reaction (4) is the main reaction to reduce the AlB2 content and increase the TiB2 content. This can effectively increase the TiB2 content in the aluminum-titanium-boron wire intermediate alloy, reduce the impurity content, and improve its refining effect.

[0063] Specifically, compared to Example 2, Example 1 has a higher proportion of potassium fluorotitanate, a higher degree of reaction in the first stage (1), and a higher degree of reaction in the first stage, resulting in a higher TiB2 content. Compared to Example 3, Example 1 also has a higher proportion of potassium fluorotitanate, resulting in a higher TiB2 content. Compared to Example 4, Example 1 has a higher proportion of potassium fluorotitanate, but in the mixture, the proportion of potassium fluorotitanate in the mixture of Example 4 is also lower than that of Example 1, and its TiB2 content is lower than that of Example 1.

[0064] Compared with Example 4, Example 2 has the same total ratio of potassium fluoroborate and potassium fluorotitanate, but the proportion of potassium fluorotitanate in the composite material of Example 2 is higher, and the TiB2 content of Example 2 is higher than that of Example 4.

[0065] Furthermore, the TiB2 content in all the above examples is higher than that in the comparative example.

[0066] Therefore, the technical solution of this application effectively increases the TiB2 content in the aluminum-titanium-boron wire master alloy, reduces the impurity content, and improves its refining effect.

[0067] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for smelting and producing an aluminum-titanium-boron wire master alloy, characterized in that: Includes the following steps: S1: Raw material selection: Weigh the raw materials according to the mass ratio of pure aluminum, potassium fluoroborate, and potassium fluorotitanate 1:0.24~0.27:0.1~0.12, wherein the aluminum content of the pure aluminum is >99.70%; and mix a portion of potassium fluorotitanate with all of the potassium fluoroborate to obtain a mixture, wherein the mass ratio of potassium fluoroborate to potassium fluorotitanate in the mixture is 2.4~2.8:1; S2: Aluminum melting and batching: Melt aluminum ingots to obtain aluminum liquid. When the temperature of the aluminum liquid reaches 700~800℃, add the mixture and the remaining potassium fluorotitanate in sequence at 3~5 min intervals according to the mass ratio of step S1, and continue stirring. S3: Reduction reaction: During the stirring process, the temperature change is monitored every 5 minutes. The stirring is continued for 20 to 40 minutes to complete the reduction reaction. After the reduction reaction is completed, the salt produced is poured out first, and then the aluminum-titanium-boron intermediate alloy is poured out as an ingot. S4: Slag Refining: The aluminum-titanium-boron intermediate alloy ingot obtained in S3 is melted again and slag is removed by adding aluminum alloy slag remover; S5: Stirring and degassing: Adjust the temperature of the aluminum liquid after slag removal and refining, and stir again to remove gas, slag, and purify. S6: Rolling: After degassing and slag removal, the molten aluminum is guided through a flow channel into the continuous casting production line, where it is stirred and rolled into aluminum-titanium-boron rods.

2. The aluminum-titanium-boron wire master alloy smelting production process according to claim 1, characterized in that: In step S4, the temperature of the molten aluminum needs to be maintained at 720~760℃ during the slag removal process.

3. The aluminum-titanium-boron wire master alloy smelting production process according to claim 1, characterized in that: In step S5, the temperature of the degassing and slag removal process is controlled at 740~780℃.

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