Zirconium poisoning resistant aluminum alloy grain refiner

Abstract

The invention provides an anti-zirconium poisoning aluminum alloy grain refiner, and belongs to the technical field of refiners. The refiner is prepared from the following components in percentage by mass: 4.8 to 5.5 percent of Ti, 0.8 to 1.5 percent of B, 0.02 to 0.25 percent of Mg, 0.02 to 0.12 percent of Cu, 0.02 to 0.15 percent of V, 0.02 to 0.1 percent of Nb, 0.02 to 0.15 percent of Er and the balance of Al. By adding Ti, Mg, Cu and other elements, the elements are enriched on the surfaces of TiB2 particles, enrichment of Zr on an interface is hindered, and therefore the problem of zirconium poisoning is solved, meanwhile, grains of the zirconium-containing aluminum alloy can be efficiently refined, the mechanical property and the yield of the aluminum alloy are improved, and the production cost is reduced; meanwhile, the method for preparing the aluminum alloy grain refiner resistant to zirconium poisoning is simple, raw materials are rich, and the aluminum alloy grain refiner is suitable for industrial mass production.

Description

Technical Field

[0001] The invention relates to the technical field of grain refiners, and in particular to a grain refiner for zirconium-poisoning-resistant aluminum alloys. Background Art

[0002] Aluminum alloys are widely used in aerospace, automobile manufacturing, electronic appliances, building structures and other fields due to their light weight, high strength, good electrical and thermal conductivity, and excellent corrosion resistance. However, the mechanical properties and processing properties of aluminum alloys are significantly affected by their grain size. Grain refinement is one of the important means to improve the comprehensive properties of aluminum alloys. Therefore, the development of effective grain refiners has become a key area of ​​aluminum alloy material research.

[0003] At present, the grain refiner used for aluminum alloy is Al-5Ti-1B. When this refiner is used for zirconium-containing aluminum alloy, its grain refinement effect will be significantly reduced. This phenomenon is called "zirconium poisoning". It is mainly because when the Zr content is too high, it will interact with the refiner (such as Al-Ti-B), causing the refiner to fail, which directly affects the performance and quality of aluminum alloy products. For this reason, the market has developed Al-Ti-C refiner to solve the problem of zirconium poisoning, but its refinement effect is still insufficient. For example, Al-Ti-C refiner will cause the grain structure to be too large in aluminum alloys containing elements such as Zr, Cr and Mn, which limits the further improvement of the performance of zirconium-containing aluminum alloys. At the same time, the uniformity of performance and yield rate are also affected; in addition, the TiC particles in Al-Ti-C are unstable at high temperatures, which is also the reason for the unstable refinement of this refiner. Summary of the invention

[0004] In view of the defects of the prior art, the present invention prepares a zirconium poisoning resistant aluminum alloy grain refiner, which not only solves the "zirconium poisoning" problem of zirconium-containing aluminum alloys, but also can achieve efficient grain refinement, thereby improving the mechanical properties of the aluminum alloy.

[0005] In order to achieve the above purpose, the present invention solves the technical problem by adopting the following technical solutions:

[0006] In a first aspect, the present invention provides a zirconium poisoning resistant aluminum alloy grain refiner, the refiner comprising the following components in mass percentage: Ti 4.8-5.5%, B 0.8-1.5%, Mg0.02-0.25%, Cu 0.02-0.12%, V0.02-0.15%, Nb 0.02-0.1%, Er0.02-0.15%, and the balance is Al.

[0007] In some embodiments, the refiner includes the following components in mass percentage: Ti 5.2%, B 1.2%, Mg 0.15%, Cu 0.08%, V 0.09%, Nb 0.06%, Er 0.09%, and the balance is Al.

[0008] In a second aspect, the present invention provides a method for preparing a zirconium poisoning resistant aluminum alloy grain refiner, the preparation method comprising the following steps:

[0009] S1. Stir and melt the aluminum ingot at 800-850°C to obtain aluminum liquid;

[0010] S2. Potassium fluorotitanate and potassium fluoroborate are mixed and added to the aluminum liquid of step S1 for reaction. After the reaction, fluoride salts on the surface of the alloy are removed and the aluminum liquid is kept at 750°C-800°C;

[0011] S3. Continue to add pure metal or alloy, keep warm for 25-35 minutes after melting completely, then refine and remove slag, cast and mold at 720℃-750℃ to obtain zirconium poisoning resistant aluminum alloy grain refiner.

[0012] In some embodiments, in step S1, the stirring power is 150-200KW.

[0013] In some embodiments, in step S2, the reaction time is 15-30 minutes.

[0014] In some embodiments, in step S3, the pure metal is one or more of Ti, Mg, Cu, V, Nb, Er, and the purity is ≥99.8%; the alloy is one or more of Ti-based, Mg-based, Cu-based, V-based, Nb-based, and Er-based.

[0015] For example, it may be a combination of Ti, Mg, Cu, V, Nb and Er, a combination of Ti, Mg and Cu, a combination of V, Nb and Er, a combination of Ti and Mg, a combination of Cu and V, and a combination of Nb and Er.

[0016] In a third aspect, the present invention provides a grain refiner prepared by using the preparation method of the zirconium poisoning resistant aluminum alloy grain refiner.

[0017] In a fourth aspect, the present invention also provides a use of the refiner in aluminum alloy refinement.

[0018] In some embodiments, the amount of the refiner is 0.1-0.3%.

[0019] In some embodiments, the grain size of the aluminum alloy after refinement is 110 μm.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The invention prepares a zirconium poisoning resistant aluminum alloy grain refiner, wherein the grain refiner is formed by adding elements such as Ti, Mg, and Cu to TiB 2 The surface of the particles is enriched, which hinders the enrichment of Zr on the interface, thereby solving the problem of zirconium poisoning. At the same time, it can efficiently refine the grains of zirconium-containing aluminum alloys. The grain size of the refined aluminum alloy is 110μm, thereby improving the mechanical properties and yield rate of the aluminum alloy, increasing the total yield strength from the original 560MPa to 610MPa, and the elongation from 9% to 12%, reducing the production cost, which is conducive to the development of refiner technology.

[0022] At the same time, the method for preparing the grain refiner for aluminum alloy resistant to zirconium poisoning is simple, the raw materials are abundant, and it is suitable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 1 is a microscopic morphology diagram of the Al-Ti-BN refiner of the present invention, in which: (1) is the refiner of Example 1, (2) is the refiner of Example 2, and (3) is the refiner of Example 3.

[0025] Figure 2 It is a grain morphology diagram of the unrefined aluminum alloy of the present invention and the 7055 aluminum alloy refined by the Al-Ti-BN refiner of Example 1 and the commercially available Al-Ti-C refiner.

[0026] Figure 3 This is a grain morphology diagram of 7055 aluminum alloy refined by the Al-Ti-BN refiner of Example 2 of the present invention.

[0027] Figure 4 This is a grain morphology diagram of 7055 aluminum alloy refined by the Al-Ti-BN refiner of Example 3 of the present invention. DETAILED DESCRIPTION

[0028] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0030] In the present invention, the terms "first", "second", "third", etc. in "the first aspect", "the second aspect", "the third aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0031] In the present invention, the test methods used are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0032] In the present invention, the purity of Ti, Mg, Cu, V, Nb and Er is ≥99.8%.

[0033] In the present invention, the zirconium poisoning resistant aluminum alloy grain refiner is prepared in two steps:

[0034] 1. Prepared by reactive salt method:

[0035] K 2 TiF 6 +KBF 4 +Al→TiB 2 +TiAl 3 +K 2 TiF 6 +KAIF 4 .

[0037] 2. Alloying

[0038] Elements such as Ti, Mg, and Cu are added to obtain a molten alloy.

[0039] Example 1

[0040] A grain refiner for aluminum alloys resistant to zirconium poisoning, wherein the preparation method of the grain refiner comprises the following steps:

[0041] 1. Add 800Kg 99.7% aluminum ingot into the smelting furnace, heat it to 830℃ and stir it to melt completely, with a stirring power of 170KW;

[0042] 2. Mix 25 kg potassium fluorotitanate and 13 kg potassium fluoroborate evenly and add them into the smelting furnace for reaction for 20 minutes;

[0043] 3. After the reaction is completed, pour out the molten salt on the surface of the alloy. After pouring, add 5 kg of slag cleaning agent (calcium fluoride) to clean the remaining fluoride salt on the surface of the alloy;

[0044] 4. After cleaning, pour the aluminum liquid into the holding furnace, add 10Kg titanium powder (Ti), 5.5kg magnesium powder (Mg), 2.3Kg copper powder (Cu), 2Kg vanadium powder (V), 1.5Kg niobium powder (Nb), 2Kg erbium powder (Er) at 780℃, keep warm for 30 minutes after the added metal is completely melted, pass argon gas for refining and degassing for 20 minutes, clean the slag on the surface of the alloy after refining and degassing, and continuously cast and roll the alloy into a wire rod with a diameter of 9.5mm at 735℃. The cross-sectional area of ​​the continuous casting ingot is 2800mm 2 , the ingot rolling temperature is 320℃, and Al-Ti-BN grain refiner is obtained.

[0045] The prepared Al-Ti-BN grain refiner contains 5.2% Ti, 1.2% B, 0.15% Mg, 0.08% Cu, 0.09% V, 0.06% Nb, 0.09% Er and the balance is Al.

[0046] Example 2

[0047] A grain refiner for aluminum alloys resistant to zirconium poisoning, wherein the preparation method of the grain refiner comprises the following steps:

[0048] 1. Add 800Kg 99.7% aluminum ingots into the smelting furnace, heat it to 800℃ and stir it until it is completely melted. The stirring power is 200KW.

[0049] 2. Mix 26 kg potassium fluorotitanate and 10 kg potassium fluoroborate evenly and add them into the smelting furnace for reaction for 30 minutes;

[0050] 3. After the reaction is completed, pour out the molten salt on the surface of the alloy. After pouring, add 4 kg of slag cleaning agent (calcium fluoride) to clean the remaining fluoride salt on the surface of the alloy;

[0051] 4. After cleaning, pour the aluminum liquid into the holding furnace, add 10Kg titanium powder (Ti), 5.5kg magnesium powder (Mg), 2.3Kg copper powder (Cu), 2Kg vanadium powder (V), 1.5Kg niobium powder (Nb), 2Kg erbium powder (Er) at 800℃, keep warm for 35 minutes after the added metal is completely melted, pass argon gas for refining and degassing for 15 minutes, clean the slag on the surface of the alloy after refining and degassing, and continuously cast and roll the alloy into a wire rod with a diameter of 9.5mm at 750℃. The cross-sectional area of ​​the continuous casting machine ingot is 2000mm 2 , the ingot rolling temperature is 300℃, and Al-Ti-BN grain refiner is obtained.

[0052] The prepared Al-Ti-BN grain refiner contains 4.8% Ti, 1.5% B, 0.02% Mg, 0.02% Cu, 0.15% V, 0.1% Nb, 0.02% Er and the balance is Al.

[0053] Example 3

[0054] A grain refiner for aluminum alloys resistant to zirconium poisoning, wherein the preparation method of the grain refiner comprises the following steps:

[0055] 1. Add 800Kg 99.7% aluminum ingot into the melting furnace, heat it to 850℃ and stir it to melt completely, with a stirring power of 150KW;

[0056] 2. Mix 24 kg potassium fluorotitanate and 15 kg potassium fluoroborate evenly and add them into the smelting furnace for reaction for 15 minutes;

[0057] 3. After the reaction is completed, pour out the molten salt on the surface of the alloy. After pouring, add 6 kg of slag cleaning agent (calcium fluoride) to clean the remaining fluoride salt on the surface of the alloy;

[0058] 4. After cleaning, pour the aluminum liquid into the holding furnace, add 10Kg titanium powder (Ti), 5.5kg magnesium powder (Mg), 2.3Kg copper powder (Cu), 2Kg vanadium powder (V), 1.5Kg niobium powder (Nb), 2Kg erbium powder (Er) at 750℃, keep warm for 25 minutes after the added metal is completely melted, pass argon gas for refining and degassing for 30 minutes, clean the slag on the surface of the alloy after refining and degassing, and continuously cast and roll the alloy into a wire rod with a diameter of 9.5mm at 720℃. The cross-sectional area of ​​the continuous casting machine ingot is 3500mm 2 , the ingot rolling temperature is 350℃, and Al-Ti-BN grain refiner is obtained.

[0059] The prepared Al-Ti-BN grain refiner contains 5.5% Ti, 0.8% B, 0.25% Mg, 0.12% Cu, 0.02% V, 0.02% Nb, 0.15% Er and the balance is Al.

[0060] Test Example 1

[0061] The microstructure of the Al-Ti-BN grain refiner prepared in Example 1 was observed and analyzed using a scanning electron microscope.

[0062] Select 20mm thick samples and grind them from coarse to fine (200#, 400#, 800#, 1200#, 1600#, 2000#, 3000#). After grinding, polish them with a polishing paste with a particle size of 0.5μm until there are no obvious scratches on the surface and the surface is bright. After polishing, corrode the sample with 5% HF solution for 30s, then rinse off the corrosive solution with deionized water, and then observe the structure of the sample with a metallographic optical microscope and take photos.

[0063] Depend on Figure 1 It can be seen that TiAl in Al-Ti-BN grain refiner 3 and TiB 2 Phase, Al 3 Ti exists in large blocks, while the small ones are TiB 2 The refiners prepared in Examples 2 and 3 are the same as the refiners prepared in Example 1, and are not described in detail here.

[0064] Test Example 2

[0065] 1. Refining 7055 aluminum alloy with the Al-Ti-BN refiner of Example 1 and the commercially available Al-Ti-C refiner respectively, the steps comprising:

[0066] 7055 aluminum alloy (Al-8Zn-2.5Cu-2Mg-0.2Zr) was placed in a 850°C melting furnace, heated until the raw material was completely melted and kept warm for 30 minutes, and argon was passed through for refining and degassing for 20 minutes. After refining and degassing, 0.2% of the weight of the 7055 aluminum alloy was added at 750°C to obtain aluminum melt, which was kept warm at 735°C for 30 minutes and poured into a metal mold. The refined 7055 aluminum alloy was obtained by cooling and demolding. The refinement effect of the two refiners on the 7055 aluminum alloy was analyzed under the polarizer mode of the metallographic optical microscope.

[0067] Depend on Figure 2-4It can be seen that when different refiners are used, the grain refining effect of the 7055 aluminum alloy is greatly different. The grains of the 7055 aluminum alloy ingot refined by the Al-Ti-BN refiner of the present invention are much smaller than the grains of the 7055 aluminum alloy ingot refined by the commercially available Al-Ti-C refiner. The grain size of the aluminum alloy after refinement by the Al-Ti-BN refiner is 110 μm, while the grain size of the aluminum alloy after refinement by the Al-Ti-C refiner is 190 μm, indicating that the Al-Ti-BN refiner of the present invention has a good refining effect, and does not have the "zirconium poisoning" phenomenon, and has wide practicality.

[0068] 2. Mechanical properties test

[0069] Before refinement, the grain size of 7055 aluminum alloy was 210μm, the yield strength was 560MPa, and the elongation was 9%. According to GB / T228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method", the refined 7055 aluminum alloy was subjected to yield strength test and elongation test, respectively, with a tensile speed of 1mm / min.

[0070] Table 1 Performance test results of aluminum alloys after different refinements

[0071]

[0072] It can be seen from Table 1 that after the aluminum alloy is refined by the refiners of Examples 1-3, its yield strength and elongation are substantially higher than those of the aluminum alloy refined by the commercially available Al-Ti-C refiner, which indicates that the refiner of the present invention has a good refinement effect. Refining the aluminum alloy by using the refiner can improve the mechanical properties of the aluminum alloy, thereby improving the processing feasibility and yield rate.

[0073] In summary, the present invention prepares an Al-Ti-BN refiner by changing the effective core TiB 2 The interface of the particles solves the problem that the enrichment of zirconium at the interface causes the effective core to fail. The refiner can be used to efficiently refine the grains of zirconium-containing aluminum alloys, thereby improving the mechanical properties and yield of the aluminum alloy. The grain size of the refined aluminum alloy is 110μm, the yield strength is increased from the original 560MPa to 610MPa, and the elongation is increased from 9% to 12%, which reduces the production cost and has a wide range of applicability.

[0074] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A zirconium poisoning resistant aluminum alloy grain refiner, characterized in that: The refiner comprises the following components in mass percentage: Ti 4.8-5.5%, B 0.8-1.5%, Mg 0.02-0.25%, Cu 0.02-0.12%, V 0.02-0.15%, Nb 0.02-0.1%, Er 0.02-0.15%, and the balance is Al.

2. The zirconium poisoning resistant aluminum alloy grain refiner according to claim 1, characterized in that: The refiner includes the following components in mass percentage: Ti 5.2%, B 1.2%, Mg 0.15%, Cu 0.08%, V 0.09%, Nb 0.06%, Er 0.09%, and the balance is Al.

3. A method for preparing a zirconium poisoning resistant aluminum alloy grain refiner, characterized in that: The preparation method comprises the following steps: S1. Stir and melt the aluminum ingot at 800-850°C to obtain aluminum liquid; S2. Potassium fluorotitanate and potassium fluoroborate are mixed and added to the aluminum liquid in step S1 for reaction. After the reaction is completed, fluoride salts on the surface of the alloy are removed and the aluminum liquid is kept at 750°C-800°C; S3. Continue to add pure metal or alloy, keep warm for 25-35 minutes after melting completely, then refine and remove slag, cast and mold at 720℃-750℃ to obtain zirconium poisoning resistant aluminum alloy grain refiner.

4. The preparation method according to claim 3, characterized in that: In step S1, the stirring power is 150-200KW.

5. The preparation method according to claim 3, characterized in that: In step S2, the reaction time is 15-30 minutes.

6. The preparation method according to claim 3, characterized in that: In step S3, the pure metal is one or more of Ti, Mg, Cu, V, Nb, Er, and the purity is ≥99.8%; the alloy is one or more of Ti-based, Mg-based, Cu-based, V-based, Nb-based, Er-based.

7. A refiner prepared by the preparation method according to any one of claims 3 to 6.

8. Use of the refiner according to any one of claims 1 to 2 and claim 7 in the refinement of aluminum alloys.

9. The use according to claim 8, characterized in that: The dosage of the refiner is 0.1-0.3%.

10. The use according to claim 8, characterized in that: The grain size of the aluminum alloy after refinement is 110 μm.

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