Preparation method of four-step high-quality Al-Ti-B grain refiner and application thereof

Abstract

The application discloses a four-step high-quality Al-Ti-B grain refiner preparation method and application thereof, and a preparation method of the refiner, which comprises the following steps: 1) after aluminum water is heated to 700-800 DEG C, degassing is carried out, then KBF4 and K2TiF6 mixed materials are added into the aluminum water for reaction in four times; 2) 22-25 wt% of the KBF4 and K2TiF6 mixed materials are added for the first time, after reaction, the water slag is poured out, alloying is carried out for 3-5 min, and residual water slag is removed; 3) 24-27 wt% of the KBF4 and K2TiF6 mixed materials are added for the second time, after feeding is completed, alloying is carried out for 5-10 min, after reaction, the water slag is poured out; 4) the step 3) is repeated twice to complete third and fourth feeding reactions; wherein, 24-27 wt% of the KBF4 and K2TiF6 mixed materials are added for the third time, and the remaining KBF4 and K2TiF6 mixed materials are added for the fourth time; 5) the flow tank is transferred into a casting furnace, degassing and standing are carried out, surface dross is removed, then trapezoidal strip ingots are directly cast or are rolled into wires by a continuous casting and rolling machine. The application has the advantages of simple operation, convenient industrial production, high product quality, small dosage and good refining effect.

Description

TECHNICAL FIELD

[0001] The present application relates to a four-step method for preparing high-quality Al-Ti-B grain refiner and its application, and belongs to the technical field of preparing Al-Ti-B grain refiner. BACKGROUND

[0002] Aluminum and its alloys have been widely used in the fields of aviation, aerospace, ship, automobile, machinery, building, decoration, packaging and household appliances, etc. due to their small density, high specific strength, excellent electrical conductivity and thermal conductivity, corrosion resistance, good cost performance, good modeling and comprehensive performance. At present, the production of aluminum is second only to steel and ranks first among various non-ferrous metals.

[0003] With the wide application of aluminum profiles, especially in the field of high-tech, the subsequent deep processing process puts strict requirements on the organization of aluminum ingot. In order to obtain excellent mechanical properties and processing properties of aluminum and its alloys, it is necessary to obtain aluminum and aluminum alloy ingots with qualified chemical composition, fine and uniform organization, low gas content and non-metallic inclusion. Grain size and morphology are the most important characteristics of as-cast structure, and equiaxed grains are the best as-cast structure. The micro-fining treatment of aluminum and its alloys can obtain fine and uniform cast ingot, and the surface finish of the refined aluminum and its alloys is good, which greatly improves the use value of aluminum products. In addition, the refined aluminum and its alloys can greatly improve the yield and reduce the waste rate in the melting and casting process.

[0004] The micro-fining treatment of aluminum and its alloys is an important research branch in the aluminum processing industry, which plays an important role in improving the quality of aluminum materials, increasing the yield of aluminum products, improving the mechanical properties and cold and hot processing properties of aluminum and its alloys.

[0005] With the development of society, customers have higher and higher quality requirements for refiners. In order to meet the needs of customers, the inventor specially develops a four-step method for preparing high-quality Al-Ti-B grain refiner, which can be used for the refinement of high-quality products. SUMMARY

[0006] The present application provides a four-step method for preparing high-quality Al-Ti-B grain refiner and its application, which is used to meet the needs of high-quality products.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0008] A four-step method for preparing high-quality Al-Ti-B grain refiner, comprising the following steps:

[0009] 1) After the aluminum water is heated to 700-800℃, the up and down stirring function of the induction furnace is started, argon is passed into the aluminum water to remove gas, then the KBF4 and K2TiF6 mixed material is transmitted into the aluminum water by the integrated salt mixing gas delivery system for four times, that is, the KBF4 and K2TiF6 mixed material is added for four times;

[0010] 2) First time: evenly add 22-25wt% of KBF4 and K2TiF6 mixed material into the aluminum water by the integrated salt mixing gas delivery system, control the feeding time for 10-15min, then pour out the water slag, alloy at 700-800℃ for 3-5min, evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual water slag;

[0011] 3) Keep the temperature at 700-800℃, carry out the second feeding reaction, add 24-27wt% of KBF4 and K2TiF6 mixed material, control the feeding time for 5-8min, evenly add the KBF4 and K2TiF6 mixed material by the integrated gas delivery system, after the feeding is completed, alloy at 700-800℃ for 5-10min, pour out the water slag after the reaction is completed, evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual water slag;

[0012] 4) Repeat step 3) twice to complete the third and fourth feeding reactions respectively; among them, add 24-27wt% of KBF4 and K2TiF6 mixed material for the third time, and add the remaining KBF4 and K2TiF6 mixed material for the fourth time;

[0013] 5) After adjusting the temperature of the obtained molten liquid to 720-800℃, transfer it into a casting furnace through a runner, let the molten liquid stand for 10-30min in the casting furnace to remove gas, remove the surface dross, then directly cast into a ladder-shaped strip ingot or roll it into a wire rod through a continuous casting and rolling machine.

[0014] The stirring power in each step is 300KW, and the electromagnetic frequency is 75HZ. Stirring is in a state until the reaction is completed, and it is turned off only when the acid water slag is poured.

[0015] The KBF4 and K2TiF6 mixed material in the application is added into the aluminum water for four times. The inventor found through long-term research and development practice that under the above specific process conditions, the feeding step of the KBF4 and K2TiF6 mixed material has a greater impact on the quality of the refining agent. Too many feeding steps will lead to the growth of the quality particles, and too few feeding steps will lead to uneven distribution of TiAl3 and TiB2 particles inside, and too few particles will reduce the refining ability during subsequent use.

[0016] The Al-Ti-B product produced by the application has fine TiB2 and TiAl3 particles with uniform dispersion, and the oxide and boride in the internal structure are effectively controlled, which can meet the requirements of high-quality aluminum and aluminum alloy material refining treatment.

[0017] The light calcium carbonate can effectively adsorb and crust the acid water residue, and facilitate complete cleaning.

[0018] In order to further ensure the quality of the refining agent, the mass ratio of KBF4 to K2TiF6 in the KBF4 and K2TiF6 mixture is 3.9:(6.1±0.5), and the mass ratio of aluminum water to the KBF4 and K2TiF6 mixture is 10:(4-6).

[0019] The mixing of KBF4 and K2TiF6 is completed on the integrated salt mixing and gas conveying equipment. First, KBF4 and K2TiF6 are placed in the feeding bin, then the conveying coefficient of the integrated salt mixing and gas conveying equipment is set, the first automatic weighing and mixing system of the integrated salt mixing and gas conveying equipment is started, KBF4 and K2TiF6 are weighed according to the calculated ratio, and then automatic mixing is performed until the raw materials are uniformly mixed.

[0020] The above-mentioned integrated gas conveying and feeding ensures that KBF4 and K2TiF6 mixture is uniformly added during the reaction process, and the reaction is more complete and complete. The generation of borides (TiB2, TiB3, TiB 12 , etc.) is effectively controlled.

[0021] The above-mentioned step 1) is to heat the clean aluminum water after refining and slagging to 700-800℃, and then transfer the aluminum water to the induction furnace through the aluminum water transfer system, start the up-down stirring function of the induction furnace, and at the same time, pass argon into the aluminum water to remove gas. The argon pressure in the induction furnace is 0.1-0.5Mpa.

[0022] The above-mentioned steps 2-4) need to pass argon during the reaction process, and the gas pressure is maintained at 0.1-0.5Mpa.

[0023] To further improve the quality of the grain refiner, step 5) is to adjust the temperature of the obtained melt to 720-800℃, then transfer into the casting furnace through the runner, and degassing and refining are carried out according to the following method: turn on the up-down stirring function of the casting furnace (stirring power 300KW, frequency 75Hz), at the same time, turn on the rotary degassing machine and the argon gas source, adjust the argon pressure to 0.1-0.5Mpa, the residues in the melt continuously float to the liquid surface, after 3-5min, turn off the up-down stirring function, turn off the degassing machine and turn off the argon gas source, and the liquid surface residues are removed, the process (referring to the process from "turning on the up-down stirring function of the casting furnace" to "removing the liquid surface residues") is repeated for 3-4 times until the liquid surface is clean; after the degassing and refining are completed, turn off the degassing machine, the up-down stirring function of the induction furnace and the gas source, remove the surface residues until the liquid surface is clean, and after the alloy liquid is placed for ≤10min, start preparing for casting or continuous casting and rolling.

[0024] The total time of the above degassing and refining is controlled to be ≤40min.

[0025] The above casting or continuous casting and rolling: when the temperature of the alloy liquid is 720-750℃, start casting or continuous casting and rolling, the alloy liquid in the furnace flows into the casting machine through the runner to directly produce Al-Ti-B alloy trapezoidal long ingots or flows into the continuous casting and rolling machine to produce Al-Ti-B alloy wires.

[0026] The technologies not mentioned in the present application refer to the prior art.

[0027] The four-step method for preparing high-quality Al-Ti-B grain refiner of the present application is simple to operate and convenient for industrial production; high-quality Al-Ti-B grain refiner can be prepared, and the prepared Al-Ti-B grain refiner has the following characteristics: in the longitudinal section of any 1cm 2 , 95% of the TiB2 particles are <0.5μm, the average size is about 0.11μm, the particles are uniformly dispersed, the homogenization is high, there are no inclusions in the ring-shaped TiB2 agglomerates and linear agglomerates; in the longitudinal section of any 1cm 2 , 99.7% of the TiAl3 particles are <6μm, and the average size of the TiAl3 particles is 2-4μm, which can be used to prepare high-quality products, the dosage is small, and the effect is long-lasting and durable without reducing the electrical conductivity. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the physical map of the four-step method for preparing high-quality Al-Ti-B grain refiner of the present application;

[0029] Figure 2 It is the metallographic structure of the four-step method for preparing high-quality Al-Ti-B grain refiner of the present application;

[0030] Figure 3SEM morphology picture of TiB2 particles in the four-step high-quality Al-Ti-B grain refiner of the present application;

[0031] Figure 4 Effect picture after refinement by the four-step high-quality Al-Ti-B grain refiner of the present application;

[0032] Figure 5 For Figure 4 State picture under microscope; DETAILED DESCRIPTION

[0033] In order to better understand the present application, the content of the present application is further illustrated below in combination with examples, but the content of the present application is not limited to the examples below.

[0034] Example 1

[0035] A preparation method of a four-step high-quality Al-Ti-B grain refiner, comprising the following steps:

[0036] After refining and cleaning 1 ton of aluminum water (purity 99.9wt%), the aluminum water is heated to 720℃, then transferred to an induction furnace through an aluminum water transfer system, the slag is removed, the up-down stirring function of the induction furnace is started (stirring power 300KW, frequency 75Hz), argon is blown into the aluminum water to remove gas, the argon pressure in the induction furnace is maintained at 0.3-0.4Mpa (this pressure needs to be maintained during the feeding process), then the KBF4 and K2TiF6 mixed material (the mass ratio of KBF4 to K2TiF6 is 3.9:6.1) is transferred to the aluminum water through an integrated salt mixing gas delivery system for reaction in four times, specifically as follows:

[0037] 1) The first time; 128kg of KBF4 and K2TiF6 mixed material is uniformly added into the aluminum water by using an integrated salt mixing gas delivery system, the feeding time is controlled to be 10min, after the feeding is completed, the acid water slag is poured out, the alloying is carried out for 3min under the condition that the temperature is 720℃, the light calcium carbonate is uniformly scattered on the surface of the molten liquid to remove the residual acid water slag;

[0038] 2) The temperature is maintained at 720℃, the second feeding reaction is carried out, 130kg of KBF4 and K2TiF6 mixed material is added, the feeding time is controlled to be 6min, the KBF4 and K2TiF6 mixed material is uniformly added by using an integrated gas delivery system, after the feeding is completed, the alloying is carried out for 5min under the condition that the temperature is 720℃, after the reaction is completed, the acid water slag is poured out, the light calcium carbonate is uniformly scattered on the surface of the molten liquid to remove the residual acid water slag;

[0039] 3) The step 2) is repeated twice to complete the third and fourth feeding reactions respectively; the amount of KBF4 and K2TiF6 mixed material added in the third and fourth times is 130kg respectively;

[0040] 4) The temperature of the resulting melt is adjusted to 720℃, and the melt is transferred into a casting furnace through a flow channel. The upper and lower stirring functions of the casting furnace are turned on (stirring power 300KW, frequency 75Hz). Meanwhile, the rotary degassing machine and argon gas source are turned on, and the argon pressure is adjusted to 0.2-0.3Mpa. The acid water slag in the melt continuously floats to the surface of the melt. After 3 minutes, the upper and lower stirring functions, the degassing machine and the argon gas source are turned off, and the acid water slag on the surface is removed. This process is repeated three times, and the surface is cleaned. The degassing machine, the upper and lower stirring functions of the induction furnace and the gas source are turned off, and the surface slag (oxidized slag) is removed until the surface is clean. After the alloy liquid is left to stand for 5 minutes, the alloy liquid at 720℃ is transferred into a continuous casting and rolling machine through a flow channel to produce a φ9.5mm wire rod. The product is shown in Figure 1 .

[0041] The metallographic structure diagram is shown in Figure 2 . It can be seen that the TiAl3 particles are fine and uniform, and there is no aggregation.

[0042] In any 1cm 2 longitudinal section, 99.7% of the TiAl3 particles are <6μm, the average diameter of TiAl3 is 2.68μm, and the maximum diameter is 6.83μm.

[0043] In any 1cm 2 longitudinal section, 98% of the TiB2 particles are <0.4μm, the average size is 0.11μm, the maximum size is 0.48μm, and the minimum size is 0.05μm. The distribution is dispersed and uniform, and there is no inclusion in the ring-shaped TiB2 agglomerates and linear agglomerates. It meets the industry standard 447.1-2011.

[0044] Refinement test: 500g of industrial pure aluminum is heated and melted to 720℃, and the prepared Al-Ti-B grain refiner is added in an amount of 0.2g / 100g of aluminum. After 15 minutes of heat preservation, the refined effect is shown in Figures 4-5 . The grain size at a distance of 51mm from the bottom surface of the sample is measured. After refinement, the grain size of the industrial pure aluminum can reach about 60μm, and there is no decrease in electrical conductivity.

[0045] Comparative Example 1

[0046] A five-step method for preparing high-quality Al-Ti-B grain refiner includes the following steps:

[0047] After refining 1 ton of clean aluminum water (purity 99.9wt%) to 720℃, the aluminum water is transported to the induction furnace through the aluminum water transport system, the slag is removed, the upper and lower stirring function of the induction furnace is started (stirring power 300KW, frequency 75Hz) while argon is introduced into the aluminum water to remove gas, the argon pressure in the induction furnace is maintained at 0.3-0.4Mpa, then the KBF4 and K2TiF6 mixed material (mass ratio of KBF4 to K2TiF6 is 3.9:6.1) is transported into the aluminum water through the integrated salt mixing gas delivery system in four times for reaction, as follows:

[0048] 1) First time; evenly add 128kg of KBF4 and K2TiF6 mixed material into the aluminum water using the integrated salt mixing gas delivery system, control the feeding time for 10min, after feeding is completed, pour out the acid water slag, alloy at 720℃ for 3min, evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual acid water slag;

[0049] 2) Maintain the temperature at 720℃, carry out the second feeding reaction, add 97.5kg of KBF4 and K2TiF6 mixed material, control the feeding time for 6min, evenly add KBF4 and K2TiF6 mixed material using the integrated gas delivery system, after feeding is completed, alloy at 720℃ for 5min, after reaction is completed, pour out the acid water slag, evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual acid water slag;

[0050] 3) Repeat step 2) three times to complete the third, fourth and fifth feeding reactions respectively; the amount of KBF4 and K2TiF6 mixed material added in the third, fourth and fifth times is 97.5kg;

[0051] 4) Adjust the temperature of the obtained molten liquid to 720℃, transfer into the casting furnace through the runner, start the upper and lower stirring function of the casting furnace (stirring power 300KW, frequency 75Hz), at the same time, start the rotary degassing machine and the argon gas source, adjust the argon pressure to 0.2-0.3Mpa, the acid water slag in the melt continuously floats out of the liquid surface, after 3min, turn off the upper and lower stirring function, turn off the degassing machine and turn off the argon gas source, remove the surface acid water slag (oxide slag), until the liquid surface is clean, after the alloy liquid is placed for 5min, the 720℃ alloy liquid is transferred into the continuous casting and rolling machine through the runner to produce φ9.5mm wire rod by continuous casting and rolling.

[0052] The difference between this example and example 1 is that the KBF4 and K2TiF6 mixed material is added in 5 steps. In any 1cm 2 longitudinal section of this example, 99.7% of the TiAl3 particles are <100μm, and the average diameter of TiAl3 is 24.8 microns. In any 1cm2 The TiB2 particles in the longitudinal section are 95% < 2 μm, and the average size is 2 μm.

[0053] Refining test: 500 g of industrial pure aluminum is heated and melted to 720 °C, and the prepared Al-Ti-B grain refiner is added in an amount of 0.2 g / 100 g of aluminum, and is kept for 15 minutes, and is poured into a Reynolds standard golf T-shaped mold, and the grain size at a distance of 51 mm from the bottom surface of the sample is measured, and the grain size of the refined industrial pure aluminum can reach about 100 μm, and the electrical conductivity is reduced by 1.01%.

[0054] It can be seen that after the increase of 5 steps, the particles have a significant increasing trend.

[0055] Comparative Example 2

[0056] A three-step method for preparing high-quality Al-Ti-B grain refiner includes the following steps:

[0057] After refining the clean 1 ton of aluminum water (purity 99.9 wt%), the aluminum water is heated to 720 °C, and then transferred to the induction furnace through the aluminum water transfer system, and the slag is removed, and the upper and lower stirring function of the induction furnace is started (stirring power 300 KW, frequency 75 Hz), and argon gas is introduced into the aluminum water to remove gas, and the argon pressure in the induction furnace is maintained at 0.3-0.4 Mpa, and then the KBF4 and K2TiF6 mixed material (the mass ratio of KBF4 and K2TiF6 is 3.9:6.1) is transferred to the aluminum water through an integrated salt mixing gas delivery system for reaction, specifically as follows:

[0058] 1) The first time; the integrated salt mixing gas delivery system is used to uniformly add 128 kg of KBF4 and K2TiF6 mixed material to the aluminum water, and the feeding time is controlled to be 10 min, and after the feeding is completed, the acid water slag is poured out, and the alloying is carried out for 3 min at a temperature of 720 °C, and the light calcium carbonate is uniformly scattered on the surface of the molten liquid to remove the residual acid water slag;

[0059] 2) Keep the temperature at 720 °C, and carry out the second feeding reaction, and add 195 kg of KBF4 and K2TiF6 mixed material, and control the feeding time to be 6 min, and uniformly add the KBF4 and K2TiF6 mixed material by using the integrated gas delivery system, and after the feeding is completed, the alloying is carried out for 5 min at a temperature of 720 °C, and after the reaction is completed, the acid water slag is poured out, and the light calcium carbonate is uniformly scattered on the surface of the molten liquid to remove the residual acid water slag;

[0060] 3) Repeat step 2) to complete the third feeding reaction; the amount of KBF4 and K2TiF6 mixed material added in the third feeding reaction is 195 kg;

[0061] 4) The temperature of the obtained melt is adjusted to 720°C, and the melt is transferred into a casting furnace through a flow channel. The upper and lower stirring functions of the casting furnace are turned on (stirring power 300KW, frequency 75Hz). Meanwhile, a rotary degassing machine and an argon gas source are turned on, and the argon pressure is adjusted to 0.2-0.3Mpa. The acid water slag in the melt continuously floats to the surface of the melt. After 3 minutes, the upper and lower stirring functions of the induction furnace are turned off, the degassing machine is turned off, and the argon gas source is turned off. The surface acid water slag is removed. This process is repeated three times to clean the surface of the melt. The degassing machine, the upper and lower stirring functions of the induction furnace, and the argon gas source are turned off. The surface floating slag (oxidized slag) is removed until the surface of the melt is clean. After 5 minutes, the alloy melt at 720°C is transferred into a continuous casting and rolling machine through a flow channel to produce φ9.5mm wire rods by continuous casting and rolling.

[0062] The difference between this example and Example 1 is that the KBF4 and K2TiF6 mixture is added in three steps. In any 1cm 2 longitudinal section, 91.2% of the TiAl3 particles are <15μm, and the average diameter of TiAl3 is 8.8μm. In any 1cm 2 longitudinal section, 92.6% of the TiB2 particles are <2μm, the average size is 1.86μm, and the maximum size is 5.36μm.

[0063] Refining test: 500g of industrial pure aluminum is heated and melted to 720°C. The prepared Al-Ti-B grain refiner is added in an amount of 0.2g / 100g of aluminum. After 15 minutes of heat preservation, the sample is poured into a Reynolds standard golf T-shaped mold. The grain size at a distance of 51mm from the bottom surface of the sample is measured. After refinement, the grain size of the industrial pure aluminum can reach about 86μm, and the electrical conductivity is reduced by 0.86%.

[0064] As can be seen, after reducing to three steps, the particles have a significant tendency to increase, and the particles are too few and unevenly distributed.

[0065] Comparative Example 3

[0066] A two-step method for preparing high-quality Al-Ti-B grain refiner includes the following steps:

[0067] After refining and removing the clean 1-ton aluminum water (purity 99.9wt%), the aluminum water is heated to 720°C. The aluminum water is transferred to the induction furnace through the aluminum water transfer system. The slag is removed. The upper and lower stirring functions of the induction furnace are started (stirring power 300KW, frequency 75Hz). At the same time, argon is introduced into the aluminum water for degassing. The argon pressure in the induction furnace is maintained at 0.3-0.4Mpa. Then, the KBF4 and K2TiF6 mixture (the mass ratio of KBF4 to K2TiF6 is 3.9:6.1) is transferred into the aluminum water through an integrated salt mixing and gas conveying system four times for reaction. The specific process is as follows:

[0068] 1) first time; using integrated mixed salt gas delivery system to add 128 kg of KBF4 and K2TiF6 mixture to the aluminum water, control the feeding time for 10 min, after the feeding is completed, pour the acid water residue, alloy at the temperature of 720 °C for 3 min, evenly sprinkle the light calcium carbonate on the surface of the melt, remove the residual acid water residue;

[0069] 2) maintain the temperature of 720 °C, carry out the second feeding reaction, add 390 kg of KBF4 and K2TiF6 mixture, control the feeding time for 6 min, use the integrated gas delivery system to add the KBF4 and K2TiF6 mixture evenly, after the feeding is completed, alloy at the temperature of 720 °C for 5 min, pour the acid water residue after the reaction is completed, evenly sprinkle the light calcium carbonate on the surface of the melt, remove the residual acid water residue;

[0070] 3) adjust the temperature of the obtained melt to 720 °C, transfer into the casting furnace through the runner, open the up and down stirring function of the casting furnace (stirring power 300 KW, frequency 75 Hz), at the same time, open the rotary degassing machine and argon gas source, adjust the argon pressure to 0.2-0.3 Mpa, the acid water residue in the melt continuously floats out the liquid surface, after 3 min, close the up and down stirring function, close the degassing machine and close the argon gas source, remove the liquid surface acid water residue, repeat the process for 3 times, the liquid surface is clean; close the degassing machine, the up and down stirring function of the induction furnace and close the gas source, remove the surface dross (oxidized dross), until the liquid surface is clean, after the alloy liquid is placed for 5 min, the alloy liquid at 720 °C flows into the continuous casting and rolling machine through the runner to produce φ9.5 mm wire rod by continuous casting and rolling.

[0071] The difference between this example and example 1 is that the KBF4 and K2TiF6 mixture is added in 2 steps. In any 1 cm 2 longitudinal section of this example, 91.2% of the TiAl3 particles are <15 μm, and the average diameter of TiAl3 is 8.8 microns. In any 1 cm 2 longitudinal section, 92.9% of the TiB2 particles are <2 μm, the average size is 1.83 microns, and the maximum size is 4.96 microns.

[0072] Refining test: 500 grams of industrial pure aluminum is heated and melted to 720 °C, the prepared Al-Ti-B grain refiner is added in an amount of 0.2 grams per 100 grams of aluminum, and the temperature is maintained for 15 minutes. Pour into a Reynolds standard golf T-shaped mold, measure the grain size at a distance of 51 mm from the bottom surface of the sample. The grain size of the refined industrial pure aluminum can reach about 85 μm, and the electrical conductivity is reduced by 0.82%.

[0073] As can be seen, after reducing to 2 steps, the results are closer to those of 3, but compared with example 1, there is a clear increasing trend, and the particles are too few and the uniformity is poor.

Claims

1. A process for the production of a high quality Al-Ti-B grain refiner in a four step process characterised by: It comprises the following steps: 1) After the aluminum water is heated to 700-800℃, the up and down stirring function of the induction furnace is started, argon is introduced into the aluminum water to remove gas, and then the KBF4 and K2TiF6 mixed material is transmitted into the aluminum water by the integrated salt mixing gas delivery system for four times to react; 2) First time: evenly add 22-25wt% of KBF4 and K2TiF6 mixed material into the aluminum water by the integrated salt mixing gas delivery system, control the feeding time for 10-15min, then pour out the slag, alloy at 700-800℃ for 3-5min, and evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual slag; 3) Keep the temperature at 700-800℃, and carry out the second feeding reaction, add 24-27wt% of KBF4 and K2TiF6 mixed material, control the feeding time for 5-8min, evenly add KBF4 and K2TiF6 mixed material by the integrated gas delivery system, after the feeding is completed, alloy at 700-800℃ for 5-10min, pour out the slag after the reaction is completed, evenly sprinkle light calcium carbonate on the surface of the molten liquid to remove residual slag; 4) Repeat step 3) twice to complete the third and fourth feeding reactions respectively; among them, add 24-27wt% of KBF4 and K2TiF6 mixed material for the third time, and add the remaining KBF4 and K2TiF6 mixed material for the fourth time; 5) After adjusting the temperature of the obtained molten liquid to 720-800℃, transfer it into the casting furnace through the runner, let the molten liquid stand for 10-30min in the casting furnace to remove surface dross, then directly cast into trapezoidal strip ingots or roll into wire rods through continuous casting and rolling machine to obtain high-quality Al-Ti-B grain refiner; High quality Al-Ti-B grain refiner, 95% of TiB2 particles in the longitudinal section of any 1 cm 2 are <0.5 μm, average size: 0.11 microns, the particles are uniformly dispersed, there are no ring-shaped TiB2 agglomerates and inclusions in linear agglomerates, any 1 cm 2 longitudinal section, 99.7% of TiAl3 particles are <6 μm, the average size of TiAl3 particles is 2-4 μm; The high-quality Al-Ti-B grain refiner is used for refining aluminum without reducing the electrical conductivity of aluminum; In the KBF4 and K2TiF6 mixed material, the mass ratio of KBF4 to K2TiF6 is 3.9: (6.1±0.5); the mass ratio of aluminum water to KBF4 and K2TiF6 mixed material is 10: (4-6).

2. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in claim 1, wherein the process is characterized by: Step 1) After the clean aluminum water after refining is heated to 700-800℃, it is transferred into the induction furnace by the aluminum water transfer system, the up and down stirring function of the induction furnace is started, and argon is introduced into the aluminum water to remove gas.

3. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in claim 2, wherein the process is characterized by: The argon pressure in the induction furnace is 0.1-0.5MPa.

4. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in any one of claims 1 to 3, characterized in that: In steps 2-4, argon is introduced to maintain the gas pressure at 0.1-0.5MPa during the reaction process.

5. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in any one of claims 1 to 3, characterized in that: Step 5) After adjusting the temperature of the obtained melt to 720-800℃, the melt is transferred into a casting furnace through a flow channel, and degassing and refining are performed as follows: the upper and lower stirring functions of the casting furnace are turned on, the rotary degassing machine and the argon gas source are turned on, the argon pressure is adjusted to 0.1-0.5 MPa, the residues in the melt continuously float to the surface of the melt, 3-5 min, the upper and lower stirring functions are turned off, the degassing machine is turned off, the argon gas source is turned off, and the surface residues are removed, the process is repeated 3-4 times until the surface is clean; after the degassing and refining are completed, the degassing machine, the upper and lower stirring functions of the induction furnace, and the gas source are turned off, the surface residues are removed until the surface is clean, the alloy liquid is left to stand for ≤10 min, and then casting or continuous casting and rolling is prepared.

6. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in claim 5, wherein the process is characterized by: The total time for degassing and refining is controlled to be ≤40 min.

7. The four-step process for the production of high quality Al-Ti-B grain refiner as claimed in any one of claims 1 to 3, characterized in that: Casting or continuous casting and rolling: when the temperature of the alloy liquid is 720-750℃, casting or continuous casting and rolling is started, the alloy liquid in the furnace is flowed into a casting machine through a flow channel to directly produce Al-Ti-B alloy trapezoidal strip ingots or flowed into a continuous casting and rolling machine to produce Al-Ti-B alloy wires.

8. Use of the four-step high-quality Al-Ti-B grain refiner produced by the production method according to any one of claims 1 to 7, characterized in that: For the refinement of aluminum, the amount is 0.1-0.3 g per 100 g of aluminum.

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