A method for purifying aluminum alloy by combined action of pulse magnetic field and foam ceramic filter

Abstract

The invention discloses a method for purifying aluminum alloy by the combined action of a pulse magnetic field and a foam ceramic filter, belonging to the technical field of impurity removal of aluminum alloy materials, and comprising the following steps: S1, smelting the aluminum alloy to obtain an aluminum alloy melt; S2, filtering the aluminum alloy melt through a foam ceramic filter; S3, applying a pulse magnetic field treatment to the aluminum alloy melt when the aluminum alloy melt flows through the foam ceramic filter to obtain an aluminum alloy product; the invention combines the pulse magnetic field treatment with the mechanical blocking effect of the foam ceramic filter, thereby being able to more effectively remove fine inclusions below 5 μm in the aluminum alloy melt, and the purification effect is significantly improved; at the same time, the action of the pulse magnetic field can also promote the aggregation and separation of impurities in the melt, and further improve the purification efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy material impurity removal, and in particular relates to a method for purifying aluminum alloy by combined action of a pulse magnetic field and a foam ceramic filter. Background Art

[0002] In the manufacturing and processing of aluminum alloys, purifying the aluminum alloy melt is one of the key steps to improve product quality and performance.

[0003] Traditional aluminum alloy melt purification methods mainly include flux refining, gas degassing and filtration. Flux refining removes impurities by adding flux to the melt and using the chemical reaction and physical adsorption between the flux and impurities in the melt; gas degassing is to introduce inert gas into the melt and use the floating effect of bubbles to take out the gas and some inclusions in the melt; the filtration method intercepts solid inclusions in the melt through the mechanical barrier effect of the filter medium (such as foam ceramic filter).

[0004] However, these methods all have certain limitations in practical applications. For example, flux refining may introduce new impurities, and the use and processing costs of flux are high; the gas degassing effect is affected by many factors such as melt temperature, gas flow rate and melt depth, and it is difficult to completely remove fine inclusions; although the filtering method can filter out oxide inclusions and large inclusions such as slag in the aluminum alloy melt, for some small-sized inclusions less than 10μm, especially some Fe-containing intermetallic compounds, the effect of foam ceramic filters is minimal, and for Fe impurities less than or equal to 5μm, the existing technology is unable to remove them, which seriously affects the quality of aluminum alloys. Therefore, a method for purifying aluminum alloys by the combined action of a pulsed magnetic field and a foam ceramic filter is urgently needed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for purifying aluminum alloy by the combined action of a pulsed magnetic field and a foam ceramic filter, which can not only achieve a better purification effect of 5μm impurities, but also significantly refine the aluminum alloy grains and improve the uniformity of the structure, as follows:

[0006] A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, comprising the following steps:

[0007] S1, smelting the aluminum alloy to obtain an aluminum alloy melt;

[0008] S2, filtering the aluminum alloy melt through a foam ceramic filter;

[0009] S3, applying a pulse magnetic field to the aluminum alloy melt when the aluminum alloy melt flows through the foam ceramic filter to obtain an aluminum alloy product;

[0010] During the pulse magnetic field treatment, the pulse magnetic field frequency is 10-30 Hz, the pulse magnetic field current is 40-100 A, and the pulse magnetic field current duty cycle is 15%-35%.

[0011] Foam ceramic filter is a porous ceramic product with a porosity of up to 70%-90%, a three-dimensional network skeleton and an interconnected pore structure. It is composed of aluminum oxide and chromium oxide, and is formed with the help of polyurethane foam, and then dried and sintered. It has a filtering effect on inclusions larger than 15μm in aluminum alloy melt.

[0012] Moreover, the aluminum alloy is a 6000 series aluminum alloy or a 2000 series aluminum alloy, and during the pulse magnetic field treatment, the current of the pulse magnetic field is greater than or equal to 40 and less than or equal to 50 A.

[0013] Moreover, the aluminum alloy is a 4000 series aluminum alloy or a 7000 series aluminum alloy, and during the pulse magnetic field treatment, the current of the pulse magnetic field is greater than 50 and less than or equal to 60 A.

[0014] Moreover, the aluminum alloy is a 3000 series aluminum alloy, and during the pulse magnetic field treatment, the current of the pulse magnetic field is greater than 60 and less than or equal to 80 A.

[0015] Moreover, the 3000 series aluminum alloy is 3003 aluminum alloy (Al—Mn series aluminum alloy), and during the pulse magnetic field treatment, the current of the pulse magnetic field is 80 A.

[0016] Moreover, the aluminum alloy is an 8000 series aluminum alloy or a 5000 series aluminum alloy, and during the pulse magnetic field treatment, the current of the pulse magnetic field is greater than 80 and less than or equal to 100 A.

[0017] Moreover, the aluminum alloy melt is smelted at 740° C. and is fully stirred to ensure uniform chemical composition of the aluminum alloy. The heat preservation time after smelting is 10-20 minutes.

[0018] Moreover, the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the pulse magnetic field combined with foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 10-30 mm.

[0019] Moreover, when the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 710-740° C., and the magnetic field waveform is a rectangular wave.

[0020] Moreover, the method for purifying aluminum alloy is used to purify Fe impurities in the aluminum alloy, and the particle size of the iron impurities can be less than or equal to 5 μm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention provides a method for purifying aluminum alloy by the combined action of a pulsed magnetic field and a foam ceramic filter. By combining pulsed magnetic field treatment and the mechanical blocking effect of the foam ceramic filter, fine inclusions below 5 μm in the aluminum alloy melt can be more effectively removed, and the purification effect is significantly improved. At the same time, the action of the pulsed magnetic field can also promote the aggregation and separation of impurities in the melt, further improving the purification efficiency.

[0023] 2. The present invention provides a method for purifying aluminum alloy by the combined action of a pulsed magnetic field and a foam ceramic filter. The pulsed magnetic field treatment can not only purify the aluminum alloy melt, but also have a positive effect on the microstructure of the aluminum alloy. By applying an appropriate pulsed magnetic field, the grain refinement in the aluminum alloy melt can be promoted, and the uniformity of the structure can be improved, thereby enhancing the mechanical properties and corrosion resistance of the aluminum alloy.

[0024] 3. The present invention provides a method for purifying aluminum alloy by the combined action of a pulse magnetic field and a foam ceramic filter. For different series of aluminum alloys, such as 6000 series, 2000 series, 4000 series, 7000 series, 3000 series (especially 3003 aluminum alloy), 8000 series and 5000 series (especially 5005 aluminum alloy), specific pulse magnetic field treatment parameters are screened out to ensure the optimization of the purification effect. This flexibility enables the present invention to be widely used in the production and processing of various aluminum alloy materials.

[0025] 4. The present invention provides a method for purifying aluminum alloy by the combined action of a pulse magnetic field and a foam ceramic filter. Compared with the traditional flux refining method, the present invention avoids the use and treatment of flux, thereby reducing environmental pollution and costs. At the same time, pulse magnetic field treatment, as a non-contact purification method, will not cause additional pollution or damage to the aluminum alloy melt.

[0026] 5. The present invention provides a method for purifying aluminum alloy by the combined action of a pulse magnetic field and a foam ceramic filter. Due to the combined use of pulse magnetic field treatment and foam ceramic filter, the purification time of aluminum alloy melt can be significantly shortened and production efficiency can be improved. This has important economic value for enterprises that produce aluminum alloy materials on a large scale.

[0027] 6. The method for purifying aluminum alloy by the combined action of a pulsed magnetic field and a foam ceramic filter provided by the present invention is suitable for purifying Fe impurities in aluminum alloy. By optimizing the pulsed magnetic field treatment parameters (the pulsed magnetic field frequency is 10-30 Hz, the pulsed magnetic field current is 40-100 A, and the pulsed magnetic field current duty cycle is 15%-35%), Fe impurities less than or equal to 5 μm can also be effectively removed, thereby achieving efficient removal of Fe impurities, thereby meeting the strict requirements of specific aluminum alloy materials on impurity content. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The metallographic microstructure diagram of the 3003 aluminum alloy after different process treatments of the present invention; wherein, Figure 1 a is the metallographic microstructure of 3003 aluminum alloy process 1; Figure 1 b is the metallographic microstructure of 3003 aluminum alloy process 2; Figure 1 c is the metallographic microstructure of 3003 aluminum alloy process 4; Figure 1 d is the metallographic microstructure of 3003 aluminum alloy process 5; Figure 1 e is the metallographic microstructure of 3003 aluminum alloy process 3; Figure 1 f is the metallographic microstructure diagram of 3003 aluminum alloy process 6.

[0029] Figure 2 This is the metallographic microstructure diagram of 5005 aluminum alloy after different processing. DETAILED DESCRIPTION Example 1

[0030] A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, comprising the following steps:

[0031] S1, smelting the aluminum alloy to obtain an aluminum alloy melt;

[0032] S2, filtering the aluminum alloy melt through a foam ceramic filter;

[0033] S3, applying a pulse magnetic field to the aluminum alloy melt when the aluminum alloy melt flows through the foam ceramic filter to obtain an aluminum alloy product;

[0034] During the pulse magnetic field treatment, the pulse magnetic field frequency is 10 Hz, the pulse magnetic field current duty cycle is 15%; the pulse magnetic field current is greater than or equal to 40 and less than or equal to 50 A.

[0035] The aluminum alloy is a 6000 series aluminum alloy or a 2000 series aluminum alloy.

[0036] Preferably, the aluminum alloy melt is smelted at 740° C. and is stirred evenly and then kept warm for 10 minutes.

[0037] Preferably, the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the pulse magnetic field combined with foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 10 mm.

[0038] Preferably, when the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 710° C. and the magnetic field waveform is a rectangular wave.

[0039] Preferably, the method for purifying aluminum alloy is used to purify Fe impurities in aluminum alloy. Example 2

[0040] A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, comprising the following steps:

[0041] S1, smelting the aluminum alloy to obtain an aluminum alloy melt;

[0042] S2, filtering the aluminum alloy melt through a foam ceramic filter;

[0043] S3. When the aluminum alloy melt flows through the foam ceramic filter, a pulse magnetic field is applied to the aluminum alloy melt to obtain an aluminum alloy product.

[0044] Preferably, the aluminum alloy is a 4000 series aluminum alloy or a 7000 series aluminum alloy;

[0045] During the pulse magnetic field treatment, the pulse magnetic field frequency is 30 Hz, the pulse magnetic field current duty cycle is 35%; the pulse magnetic field current is greater than 50 and less than or equal to 60 A.

[0046] Preferably, the aluminum alloy melt is smelted at 740° C. and is kept warm for 20 minutes after being fully stirred.

[0047] Preferably, the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the pulse magnetic field combined with foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 30 mm.

[0048] Preferably, when the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 740° C. and the magnetic field waveform is a rectangular wave.

[0049] Preferably, the method for purifying aluminum alloy is used to purify Fe impurities in aluminum alloy. Example 3

[0050] A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, comprising the following steps:

[0051] S1, smelting the aluminum alloy to obtain an aluminum alloy melt;

[0052] S2, filtering the aluminum alloy melt through a foam ceramic filter;

[0053] S3. When the aluminum alloy melt flows through the foam ceramic filter, a pulse magnetic field is applied to the aluminum alloy melt to obtain an aluminum alloy product.

[0054] Preferably, the aluminum alloy is a 3000 series aluminum alloy, and the 3000 series aluminum alloy is a 3003 aluminum alloy. During the pulse magnetic field treatment, the pulse magnetic field frequency is 20 Hz, the pulse magnetic field current duty cycle is 25%; and the pulse magnetic field current is 80A.

[0055] Preferably, the aluminum alloy melt is smelted at 740° C. and is kept warm for 15 minutes after being fully stirred.

[0056] Preferably, the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the pulse magnetic field combined with foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 20 mm.

[0057] Preferably, when the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 725° C. and the magnetic field waveform is a rectangular wave.

[0058] Preferably, the method for purifying aluminum alloy is used to purify Fe impurities in aluminum alloy. Example 4

[0059] A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, comprising the following steps:

[0060] S1, smelting the aluminum alloy to obtain an aluminum alloy melt;

[0061] S2, filtering the aluminum alloy melt through a foam ceramic filter;

[0062] S3. When the aluminum alloy melt flows through the foam ceramic filter, a pulse magnetic field is applied to the aluminum alloy melt to obtain an aluminum alloy product.

[0063] Preferably, the aluminum alloy is a 5005 series aluminum alloy. During the pulse magnetic field treatment, the pulse magnetic field frequency is 20 Hz, the pulse magnetic field current duty cycle is 25%; and the pulse magnetic field current is 100 A.

[0064] Preferably, the aluminum alloy melt is smelted at 740° C. and is fully stirred and kept warm for 18 minutes.

[0065] Preferably, the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the pulse magnetic field combined with foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 25 mm.

[0066] Preferably, when the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 720° C., and the pulse magnetic field current waveform is a rectangular wave.

[0067] Preferably, the method for purifying aluminum alloy is used to purify Fe impurities in aluminum alloy.

[0068] Experimental Section

[0069] Experiment 1

[0070] Process 1 (control group): Take 3003 aluminum alloy, heat it to 740℃ to melt it, add 5μm Fe powder, stir evenly, and keep warm for 15min.

[0071] Process 2: Take 3003 aluminum alloy, heat it to 740℃ to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 3003 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; filter the aluminum alloy melt through a foam ceramic filter.

[0072] Process 3: Take 3003 aluminum alloy, heat it to 740°C to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 3003 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; use the technical solution of Example 3 for treatment, and the current of the pulsed magnetic field is 80 A.

[0073] Process 4: Different from process 3, the current of the pulse magnetic field is 40A.

[0074] Process 5: Different from process 3, the current of the pulse magnetic field is 60 A.

[0075] Process 6: Different from process 3, the current of the pulse magnetic field is 100 A.

[0076] Process 7: Take 6000 series aluminum alloy (6063 aluminum alloy), heat it to 740°C to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 6063 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; use the technical solution of Example 1 for treatment, and the current of the pulsed magnetic field is 40A.

[0077] Process 8: Different from process 7, the current of the pulse magnetic field is 80 A.

[0078] Process 9: Take 4000 series aluminum alloy (4032 aluminum alloy), heat it to 740°C to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 4032 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; use the technical solution of Example 2 for treatment, and the current of the pulsed magnetic field is 60 A.

[0079] Process 10: Different from process 9, the current of the pulse magnetic field is 100 A.

[0080] Process 11: Take 8000 series aluminum alloy (8011 aluminum alloy), heat it to 740°C to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 8011 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; use the technical solution of Example 3 for treatment, and the current of the pulsed magnetic field is 100 A.

[0081] Process 12: Different from process 11, the current of the pulse magnetic field is 40A.

[0082] The Fe content of the aluminum alloy after treatment by processes 1-12 was determined by energy dispersive spectrometer. The results are shown in Table 1.

[0083] Table 1 EDS results of Fe content in different aluminum alloys after different process treatments

[0084]

[0085] (Note: Fe content includes the added 1% Fe powder and the original Fe content of the aluminum alloy)

[0086] From the comparison in Table 1, it can be seen that after the treatment by process 1, the content of 5 μm iron impurities in the 3003 aluminum alloy sample is 2.24%. After filtering by pulse magnetic field combined with foam ceramic filter in process 2, the content of 5 μm iron impurities is reduced to 1.97%, and the effect is not very obvious. When the technical solution of process 3 (the present invention) is used for treatment, the content of 5 μm iron impurities is only 0.35%, which is significantly reduced. Due to the unreasonable application of current in processes 4-6, which are 40A, 60A and 100A respectively, the impurity removal effect is significantly different from that of process 3.

[0087] It can be seen from the results of processes 7 and 8 that the technical solution provided by the present invention is effective in treating Fe impurities in 6063 aluminum alloy, and changing the current has a greater impact on it.

[0088] It can be seen from the results of processes 9 and 10 that the technical solution provided by the present invention is effective in treating Fe impurities in 4032 aluminum alloy, and changing the current has a greater impact on it.

[0089] It can be seen from the results of processes 11 and 12 that the technical solution provided by the present invention is effective in treating Fe impurities in 8011 aluminum alloy, and changing the current has a greater impact on it.

[0090] During the experiment, it was found that for different series of aluminum alloys, different current sizes were used for pulse magnetic field treatment, and the effects were also different. This may be because different series of aluminum alloys have different compositions and microstructures. These differences cause aluminum alloys to respond differently to pulse magnetic field currents. For example, some aluminum alloys may contain more easily segregated elements, while others may contain more strengthening phase particles. These differences in composition and structure will affect the effect of pulse magnetic field currents on aluminum alloys.

[0091] Note: The Fe content of 3003 aluminum alloy differs from that of 6063 aluminum alloy, 4032 aluminum alloy and 8011 aluminum alloy by about 0.1-0.2%.

[0092] Experiment 2

[0093] The 3003 aluminum alloys treated by processes 1-6 in Experiment 1 were selected and observed using a metallographic microscope. The results are shown in Figure 1 , Figure 1 a is the metallographic microstructure of 3003 aluminum alloy with 1% Fe powder added (process 1). Figure 1 b is the metallographic microstructure of 3003 aluminum alloy after filtration only (process 2). Figure 1 c- Figure 1 f are the metallographic microstructures of 3003 aluminum alloy variable current (process 3-6), Figure 1 It can be seen that the average grain size of process 1 (adding 1% Fe powder) is 188.09 μm, and the average grain size of process 2 (1% Fe powder + filtration) is 187.19 μm, which is not significantly different from the average grain size of process 1; the average grain size of process 3 (adding 1% Fe powder + filtration + 80A, the present invention) is 159.92 μm, which is 15.0% lower than the average grain size of process 1; the average grain size of process 4 (1% Fe powder + filtration + 40A) is 182.58 μm, which is 2.9% lower than the average grain size of process 1; the average grain size of process 5 (1% Fe powder + filtration + 60 A) is 176.87 μm, which is 6.0% lower than the average grain size of process 1; process 6 (adding 1% Fe powder + filtration + 100 The average grain size of process A) is 156.39 μm, which is 16.9% lower than that of process 1. From the above results, it can be seen that the average grain size is reduced the most by using process 6 and the technical scheme of the present invention (process 3). Combined with the removal effect of Fe impurities in experiment 1, it can be determined that the technical scheme of the present invention (process 3) has the best effect. Grain refinement can improve the yield strength, tensile strength, hardness, plasticity and toughness, processing performance and corrosion resistance of the material.

[0094] Experiment 3

[0095] Process 13: Take 5005 aluminum alloy, heat it to 740℃ to melt it, add 5μm Fe powder (accounting for 1% of the total mass of 5005 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; filter the aluminum alloy melt through a foam ceramic filter.

[0096] Process 14: Take 5005 aluminum alloy, heat it to 740°C to melt it, add 5μm Fe powder (accounting for 1% of the total mass of the 5005 aluminum alloy melt), stir evenly, and keep warm for 15 minutes; use the process of Example 4 to treat 5005 aluminum alloy, and the current of the pulsed magnetic field is 100 A.

[0097] The Fe content and average grain size after treatment by process 13 and process 14 are shown in Table 2 and Figure 2 .

[0098] Table 2 EDS results of Fe content of different 5005 aluminum alloys after different process treatments

[0099]

[0100] (Note: Fe content includes the added 1% Fe powder and the original Fe content of the aluminum alloy)

[0101] From Table 2 and Figure 2 It can be seen that the 5005 aluminum alloy treated by process 14 (the present invention) has an Fe content of 0.34% and an average grain size of 197.8 μm, which is more efficient in removing impurities than process 13. After treatment, the grains are finer and more uniform.

Claims

1. A method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter, characterized in that: The method for purifying aluminum alloy is used to purify Fe impurities in aluminum alloy; the Fe impurities are Fe impurities less than or equal to 5 μm; the pulse magnetic field waveform is a rectangular wave; The method for purifying aluminum alloy comprises the following steps: S1, melting an aluminum alloy to obtain an aluminum alloy melt; the aluminum alloy melt is melted at a temperature of 740°C, stirred evenly, and kept warm for 10-20 minutes; S2, filtering the aluminum alloy melt through a foam ceramic filter; S3. When the aluminum alloy melt flows through the foam ceramic filter, a pulse magnetic field treatment is applied to the aluminum alloy melt to obtain an aluminum alloy product; the specific method of the pulse magnetic field treatment is to place a pulse magnetic field treatment device above the foam ceramic filter, and the distance between the pulse magnetic field treatment device and the aluminum alloy melt is 10-30 mm; During the pulsed magnetic field treatment, the pulsed magnetic field frequency is 10-30 Hz, the pulsed magnetic field current is 40-100 A, and the pulsed magnetic field current duty cycle is 15%-35%.

2. The method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter as claimed in claim 1, characterized in that: The aluminum alloy is a 6000 series aluminum alloy or a 2000 series aluminum alloy. During the pulse magnetic field treatment, the current of the pulse magnetic field is greater than or equal to 40 A and less than or equal to 50 A.

3. The method for purifying aluminum alloy by combined action of pulse magnetic field and foam ceramic filter as claimed in claim 1, characterized in that: The aluminum alloy is a 4000 series aluminum alloy or a 7000 series aluminum alloy. During the pulse magnetic field treatment, the current of the pulse magnetic field is greater than 50 A and less than or equal to 60 A.

4. The method for purifying aluminum alloy by combining pulse magnetic field and foam ceramic filter as claimed in claim 1, characterized in that: The aluminum alloy is 3003 aluminum alloy, and during the pulse magnetic field treatment, the current of the pulse magnetic field is 80 A.

5. The method for purifying aluminum alloy by combined action of pulse magnetic field and foam ceramic filter as claimed in claim 1, characterized in that: The aluminum alloy is 5005 aluminum alloy, and the current of the pulse magnetic field is equal to 100 A.

6. The method for purifying aluminum alloy by combined action of pulse magnetic field and foam ceramic filter as claimed in claim 1, characterized in that: When the aluminum alloy melt is subjected to pulse magnetic field treatment, the temperature of the aluminum alloy melt is 710°C-740°C.

Images