Aluminum alloy refining agent and preparation method and refining method thereof

Abstract

The invention provides an aluminum alloy refining agent as well as a preparation method and a refining method thereof, and the aluminum alloy refining agent comprises the following raw material components in percentage by weight: 40%-50% of MgCl2, 40%-50% of KCl, 0.1%-1% of C2Cl6, 0-5% of CaCl2 and 0-5% of BaCl2. According to the refining agent, the spinel removal effect is good, efficient deep purification of an aluminum alloy solution can be achieved, the cleanliness of aluminum alloy is greatly improved, the defects of aluminum alloy products are reduced, and then the magnesium-aluminum alloy can meet the high-plasticity requirement in the subsequent machining process. The MgCl2 fused salt with the high proportion is adopted, introduction of other alkali metal can be reduced, formation of alkali metal inclusions is reduced from the alkali metal source, meanwhile, the content of C2Cl6 is low, generation of harmful gas can be reduced, and the environment-friendly performance is good. The refining agent is low in density, the solvent melting and floating speed in alloy melt is higher, efficient degassing and deslagging can be achieved easily, the floating time of the refining agent is shortened, namely, the refining time of alloy is shortened, and the refining efficiency and environment friendliness of the refining agent are improved.

Description

Technical Field

[0001] This application relates to the field of aluminum alloy technology, and in particular to an aluminum alloy refining agent and its preparation and refining methods. Background Technology

[0002] In the production of high-magnesium aluminum alloys, casting is a common mass production method. During casting, the molten aluminum at high temperatures undergoes a series of complex reactions with oxidizing media, generating a certain amount of active hydrogen, oxides, and other compounds. If these are not removed in time, they can easily lead to crack propagation, severely affecting the plasticity of the high-magnesium aluminum alloy. To obtain a purer aluminum-magnesium alloy melt, refining agents are usually used to degas and remove impurities. However, with increasing demands for product performance, the purification effect of traditional refining agents is not ideal, resulting in high-magnesium aluminum alloys with numerous defects that are difficult to meet the high plasticity requirements during processing. Summary of the Invention

[0003] Therefore, it is necessary to provide an aluminum alloy refining agent and its preparation and refining methods, with the aim of reducing defects in aluminum alloy products.

[0004] The first aspect of this application provides an aluminum alloy refining agent, wherein the raw material components of the refining agent, by weight percentage, include 40%~50% MgCl2, 40%~50% KCl, 0.1%~1% C2Cl6, 0~5% CaCl2 and 0~5% BaCl2.

[0005] The refining agent of this application has a good effect on removing spinel, which can achieve efficient and deep purification of aluminum alloy melt, greatly improve the cleanliness of aluminum alloy, reduce defects in aluminum alloy products, and enable magnesium-aluminum alloy to meet the high plasticity requirements in subsequent processing.

[0006] Furthermore, the use of a higher proportion of MgCl2 molten salt in this application can reduce the introduction of other alkali metals, thereby reducing the formation of alkali metal inclusions from the source of alkali metals. At the same time, the lower C2Cl6 content can reduce the generation of harmful gases, resulting in better environmental performance.

[0007] The Mg content in the ingot purified by the refining agent of this application is not much different from the surface average Mg content, and the element distribution is more uniform, which further reduces defects in aluminum alloy products.

[0008] The refining agent of this application has a low density, and its solvent melting and flotation speed in the alloy melt is faster, which is conducive to achieving efficient degassing and slag removal, reducing the flotation time of the refining agent, that is, reducing the refining time of the alloy, and improving the refining efficiency and environmental friendliness of the refining agent.

[0009] The refining agent of this application has a good wetting effect on slag. Wetting can provide additional adsorption force, ensuring that inclusions can be effectively carried out during the floating process of the refining medium, and further reducing defects in aluminum alloy products.

[0010] In some embodiments, the raw material components of the refining agent, by weight percentage, include 42%~48% MgCl2, 42%~48% KCl, 0.5%~1% C2Cl6, 1%~5% CaCl2, and 1%~5% BaCl2.

[0011] In some embodiments, the density of the refining agent is 1.5 g / cm³ to 2.0 g / cm³; and / or,

[0012] The refining agent has a melting point of 429℃~438℃.

[0013] A second aspect of this application provides a method for preparing an aluminum alloy refining agent, comprising the following steps:

[0014] The raw material components are: 40%~50% MgCl2, 40%~50% KCl, 0.1%~1% C2Cl6, 0~5% CaCl2, and 0~5% BaCl2 by weight percentage.

[0015] The MgCl2 and KCl were melted and mixed, then cooled and solidified to obtain a mixture of MgCl2 and KCl.

[0016] The mixture of MgCl2 and KCl was pulverized to obtain powder;

[0017] The powder is mixed with the remaining raw material components.

[0018] In some embodiments, the melting temperature of the MgCl2 and KCl followed by cooling and solidification is 775°C to 800°C; and / or the temperature is reduced to 20°C to 30°C.

[0019] A third aspect of this application provides a refining method for an aluminum alloy refining agent as described in the first aspect, comprising the following steps:

[0020] 1) Mix and melt the remaining raw materials in the Al-Mg alloy raw material except for magnesium raw material to obtain alloy melt;

[0021] 2) The alloy melt is first refined using the refining agent;

[0022] 3) The alloy melt after the first refining is mixed with the magnesium raw material to obtain an Al-Mg alloy melt;

[0023] 4) The Al-Mg alloy melt is refined a second time using the refining agent.

[0024] This invention addresses an improved refining method for Al-Mg alloy melts. By employing the refining agent described in this application and refining the alloy melt once before adding magnesium feedstock, the formation of spinel from SiO2, MgO, and other oxide inclusions is reduced. This significantly reduces ingot defects and solves the problem of the alloy failing to meet high plasticity requirements during processing. Furthermore, the refining method shortens refining time, improves melt purification efficiency, and reduces the generation of harmful gases.

[0025] In some embodiments, in step 1), the refining agent is used as a covering agent to cover the surface of the alloy melt, and the amount of the covering agent accounts for 3% to 6% of the weight of the alloy melt.

[0026] In some embodiments, the first refining satisfies one or more of the following characteristics:

[0027] (1) The amount of the refining agent added accounts for 0.1% to 0.6% of the weight of the alloy melt;

[0028] (2) The temperature is 730℃~750℃;

[0029] (3) The blowing time is 30 min ~ 40 min;

[0030] (4) The settling time is 10 min ~ 30 min.

[0031] In some embodiments, the second refining satisfies one or more of the following characteristics:

[0032] (1) The amount of the refining agent added is 0.1% to 0.5% of the mass of the Al-Mg alloy melt;

[0033] (2) The temperature is 730℃~750℃;

[0034] (3) The blowing time is 30 min ~ 40 min;

[0035] (4) The settling time is 10 min ~ 30 min.

[0036] In some embodiments, the Al-Mg alloy melt is subjected to degassing and slag removal treatment after the second refining.

[0037] In some embodiments, in step 3), the magnesium raw material is added at a temperature of 730°C to 740°C, and after adding the magnesium raw material, the temperature of the Al-Mg alloy melt is controlled at 740°C to 760°C and held for 2 to 3 hours.

[0038] In some embodiments, the degassing treatment is performed at a temperature of 725°C to 735°C; and / or,

[0039] The slag removal treatment temperature is 700℃~710℃. Attached Figure Description

[0040] Figure 1 The image shows the metallographic structure of the ingot prepared in Example 1.

[0041] Figure 2 The image shows the metallographic diagram of the ingot prepared in Comparative Example 1.

[0042] Figure 3 The image shows the metallographic structure of the ingot prepared in Comparative Example 2.

[0043] Figure 4 The image shows the metallographic structure of the ingot prepared in Comparative Example 3.

[0044] Figure 5 The images show the EDS and spot scan of the ingot prepared in Example 1.

[0045] Figure 6 The image shows the EDS and spot scan of the ingot prepared in Comparative Example 1.

[0046] Figure 7 EDS and spot scan images of the ingot prepared in Comparative Example 2.

[0047] Figure 8 EDS and spot scan images of the ingot prepared in Comparative Example 3.

[0048] Figure 9 This is a flowchart of the refining method in Example 2.

[0049] Figure 10 This is a SEM image of the ingot prepared in Example 2. Detailed Implementation

[0050] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0052] In a first aspect of this application, one embodiment provides an aluminum alloy refining agent, wherein the raw material components of the refining agent, by weight percentage, include 40%~50% MgCl2, 40%~50% KCl, 0.1%~1% C2Cl6, 0~5% CaCl2 and 0~5% BaCl2.

[0053] The refining agent of this application has a good effect on removing spinel, which can achieve efficient and deep purification of aluminum alloy melt, greatly improve the cleanliness of aluminum alloy, reduce defects in aluminum alloy products, and enable magnesium-aluminum alloy to meet the high plasticity requirements in subsequent processing.

[0054] Furthermore, the use of a higher proportion of MgCl2 molten salt in this application can reduce the introduction of other alkali metals, thereby reducing the formation of alkali metal inclusions from the source of alkali metals. At the same time, the lower C2Cl6 content can reduce the generation of harmful gases, resulting in better environmental performance.

[0055] The Mg content in the ingot purified by the refining agent of this application is not much different from the surface average Mg content, and the element distribution is more uniform, which further reduces defects in aluminum alloy products.

[0056] The refining agent of this application has a low density, and its solvent melting and flotation speed in the alloy melt is faster, which is conducive to achieving efficient degassing and slag removal, reducing the flotation time of the refining agent, that is, reducing the refining time of the alloy, and improving the refining efficiency and environmental friendliness of the refining agent.

[0057] The refining agent in this application has a good wetting effect on slag.

[0058] As an example, the weight percentage of MgCl2 can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, and 50%, or it can be within the range formed by any two of the above point values ​​as endpoints.

[0059] As an example, the weight percentage of KCl can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, and 50%, or it can be any two of the above point values ​​as the endpoints within a range.

[0060] As an example, the weight percentage of C2Cl6 can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1%, or it can be within a range consisting of any two of the above point values ​​as endpoints.

[0061] As an example, the weight percentage of CaCl2 can be 0, 1%, 2%, 3%, 4%, and 5%, or it can be any two of the above point values ​​as the endpoints within a range.

[0062] As an example, the weight percentage of BaCl2 can be 0, 1%, 2%, 3%, 4%, and 5%, or it can be any two of the above point values ​​as the endpoints within a range.

[0063] In some embodiments, the raw material composition of the refining agent, by weight percentage, includes 42%–48% MgCl2, 42%–48% KCl, 0.5%–1% C2Cl6, 1%–5% CaCl2, and 1%–5% BaCl2. The refining agent obtained with this raw material composition has a low density, resulting in faster solvent melting and flotation in the melt, which is beneficial for efficient degassing and slag removal. Simultaneously, it reduces the flotation time of the refining agent, thus reducing refining time and improving refining efficiency and environmental friendliness. Furthermore, using a high proportion of MgCl2 molten salt reduces the introduction of other alkali metals, minimizing the formation of alkali metal inclusions from the alkali metal source. Moreover, the low proportion of hexachloroethane contributes to the refining agent's superior environmental performance.

[0064] In some embodiments, the density of the refining agent is 1.5 g / cm³ to 2.0 g / cm³; and / or,

[0065] The refining agent has a melting point of 429℃~438℃.

[0066] A second aspect of this application, one embodiment of which provides a method for preparing an aluminum alloy refining agent, includes the following steps:

[0067] 1) By weight percentage, take 40%~50% MgCl2, 40%~50% KCl, 0.1%~1% C2Cl6, 0~5% CaCl2, and 0~5% BaCl2 as raw material components;

[0068] 2) The MgCl2 and KCl are melted and mixed, then cooled and solidified to obtain a mixture of MgCl2 and KCl;

[0069] 3) The mixture of MgCl2 and KCl is pulverized to obtain powder;

[0070] 4) Mix the powder with the remaining raw material components.

[0071] In some embodiments, in step 1), the raw materials of the refining agent are first dried in a drying oven to remove the water of crystallization on the surface of the raw materials before use.

[0072] In some embodiments, in step 2), the melting temperature is 775°C to 800°C; and / or the temperature is reduced to 20°C to 30°C.

[0073] A third aspect of this application provides a refining method for an aluminum alloy refining agent as described in the first aspect, comprising the following steps:

[0074] 1) Mix and melt the remaining raw materials in the Al-Mg alloy raw material except for magnesium raw material to obtain alloy melt;

[0075] 2) The alloy melt is first refined using the refining agent;

[0076] 3) The alloy melt after the first refining is mixed with the magnesium raw material to obtain an Al-Mg alloy melt;

[0077] 4) The Al-Mg alloy melt is refined a second time using the refining agent.

[0078] In the refining method of this embodiment, by employing the refining agent of this application and refining the alloy melt once before adding magnesium raw materials, the formation of spinel from oxide inclusions such as SiO2 and MgO in contact with Mg is reduced, thereby reducing ingot defects. Furthermore, the above refining method shortens the refining time, improves melt purification efficiency, and reduces the generation of harmful gases.

[0079] In some embodiments, in step 1), the refining agent is used as a covering agent to cover the surface of the alloy melt, and the amount of the covering agent accounts for 3% to 6% of the weight of the alloy melt.

[0080] As an example, the amount of covering agent used as a percentage of the alloy melt weight can be 3%, 4%, 5%, and 6%, or it can be within the range formed by any two of the above point values ​​as endpoints.

[0081] In some embodiments, the refining method provided in this application is applicable to the refining of magnesium-aluminum alloys. Furthermore, the refining method provided in this application is applicable to the refining of high-magnesium-aluminum alloys. It is understood that the magnesium content in high-magnesium-aluminum alloys is 2-5 wt.%.

[0082] In some embodiments, the first refining satisfies one or more of the following characteristics:

[0083] (1) The amount of the refining agent added accounts for 0.1% to 0.6% of the weight of the alloy melt;

[0084] (2) The temperature is 730℃~750℃;

[0085] (3) The blowing time is 30 min ~ 40 min;

[0086] (4) The settling time is 10 min ~ 30 min.

[0087] As an example, the amount of refining agent added during the first refining process can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6% of the weight of the alloy melt, or it can be within the range formed by any two of the above point values ​​as endpoints.

[0088] In some embodiments, in step 2), the first refining is carried out under high-purity argon gas, and the argon gas flow rate is preferably 80~120 L / min, more preferably 90~110 L / min, and most preferably 100 L / min.

[0089] In some embodiments, the second refining satisfies one or more of the following characteristics:

[0090] (1) The amount of the refining agent added is 0.1% to 0.5% of the mass of the Al-Mg alloy melt;

[0091] (2) The temperature is 730℃~750℃;

[0092] (3) The blowing time is 30 min ~ 40 min;

[0093] (4) The settling time is 10 min ~ 30 min.

[0094] As an example, during the second refining process, the amount of refining agent added can be 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% of the weight of the Al-Mg alloy melt, or it can be within the range formed by any two of the above point values ​​as endpoints.

[0095] In some embodiments, the second refining is carried out under high-purity argon gas, with the argon gas flow rate preferably being 80~120L / min, more preferably 90~110L / min, and most preferably 100L / min.

[0096] In some embodiments, the Al-Mg alloy melt is subjected to degassing and slag removal treatment after the second refining.

[0097] In some embodiments, in step 3), the magnesium raw material is added at a temperature of 730°C to 740°C. After adding the magnesium raw material, the temperature of the Al-Mg alloy melt is controlled to be ≤760°C, and held at this temperature for 2 to 3 hours. Controlling the alloy melt temperature below 760°C after adding magnesium, preferably between 740°C and 760°C, and controlling the subsequent melt holding time to within 2 to 3 hours, reduces the formation of spinel at high temperatures.

[0098] As an example, after adding magnesium, the alloy melt temperature can be controlled at 740℃, 745℃, 750℃, 755℃ and 760℃, or any two of the above point values ​​can be used as the end values ​​within the range.

[0099] In some embodiments, the degassing treatment is performed at a temperature of 725°C to 735°C; and / or,

[0100] The slag removal treatment temperature is 700℃~710℃.

[0101] Furthermore, the degassing treatment is online degassing, using a dual-rotor gas jet. The chamber temperature for online degassing is 725℃~735℃, preferably 730℃; the rotor speed is 400 r / min~500 r / min, preferably 500 r / min; the inert gas pressure is 0.2 MPa~0.3 MPa, preferably 0.2 MPa; and 1.5 kg of Al-5Ti-1B is added to the degassing box.

[0102] Furthermore, the slag removal process is an online filtration slag removal, using a ceramic filter plate as the filter material. The ceramic filter plate has a specification of 40+50ppi and a filtration temperature of 700℃~710℃.

[0103] In some embodiments, the third refining begins when the temperature is between 730°C and 750°C. The third refining uses 0 kg of refining agent, i.e., no refining agent is added. The argon gas blowing pressure is 0.2 MPa to 0.3 MPa, the blowing position moves in an M-shape, the blowing lasts for 30 min to 40 min, and after standing for 30 min to 40 min, the slag is removed.

[0104] Furthermore, the purified Al-Mg alloy melt is cast in a casting crystallizer. The melt temperature in the casting crystallizer, i.e. the casting temperature, is preferably 690℃~720℃, more preferably 700℃~710℃. The casting speed is preferably 20 mm / min~40 mm / min, more preferably 25 mm / min~35 mm / min, and most preferably 30 mm / min. Argon gas is injected for cooling during the casting process.

[0105] The following are specific examples.

[0106] Example 1

[0107] The raw material components are as follows, by weight percentage: 50% MgCl2, 40% KCl, 1% C2Cl6, 5% CaCl2 and 4% BaCl2; the aforementioned amounts of MgCl2 and KCl are melted and mixed, then cooled to 20°C to solidify, with a melting temperature of 775°C, to obtain a mixture of MgCl2 and KCl; the MgCl2 and KCl mixture is ground into powder, and then mixed evenly with the remaining raw material components to obtain a refining agent.

[0108] Commercial 5A06 alloy was placed in a drying oven and heated to 350°C to remove the crystal water on the alloy surface. The dried alloy was then placed in a melting furnace, the furnace door closed, and the temperature raised to 780°C to melt the charge. The furnace charge was held at this temperature until completely melted. After complete melting, the alloy was allowed to stand for 10 minutes, maintaining the melt temperature at 740°C. The aforementioned refining agent was added as a covering agent, with the amount of covering agent accounting for 3% of the alloy melt weight. The alloy was then refined twice using the aforementioned refining agent, the first refining lasting 10 minutes. The refining agent is used at a rate of 0.5% of the alloy melt weight. The refining agent is added and argon gas is injected to refine the alloy three times. After adding the refining agent, slag is removed 5 minutes later. After refining, the alloy is allowed to stand for 15 minutes. The second refining process takes 10 minutes. The refining agent is used at a rate of 0.5% of the alloy melt weight. The refining agent is added and argon gas is injected to refine the alloy three times. After adding the refining agent, slag is removed 5 minutes later. After refining, the alloy is allowed to stand for 15 minutes. The alloy is then degassed and filtered to remove slag. The alloy is then poured into ingots at a furnace temperature of 720℃.

[0109] The porosity defect data in the ingot are shown in Table 1; the metallographic image of the ingot is shown in... Figure 1 EDS and spot scan images of the ingot are as follows Figure 5 As shown.

[0110] Example 2

[0111] A refining agent, wherein the raw material components of the refining agent, by weight percentage, comprise:

[0112] 46% MgCl2, 45% KCl, 1% C2Cl6, 5% CaCl2 and 3% BaCl2.

[0113] The above-mentioned refining agent is used for the purification process of 20t-class engineering applications of high-magnesium content aluminum alloys. The purification process is as follows: Figure 9 As shown.

[0114] All furnace materials except Mg ingots are added to the furnace in order of their melting difficulty. The furnace is heated to above 760°C to melt the materials. The first refining process begins when the temperature reaches 745°C.

[0115] The first refining process used 30 kg of refining agent (0.1% of the alloy melt weight), argon gas was injected at a pressure of 0.3 MPa, the injection position was moved in an M-shape, and the injection lasted for 30 min. After standing for 25 min, the slag was removed, and then Mg ingots and feed were added according to the alloy composition requirements.

[0116] The second refining process begins at 747 ℃. The second refining process uses 30 kg of refining agent (0.1% of the alloy melt weight), argon gas is injected at a pressure of 0.3 MPa, and the injection position moves in an M-shape. The injection lasts for 30 min, and after standing for 25 min, the slag is removed, the composition is measured, and appropriate material is added.

[0117] The third refining process begins when the temperature reaches 744 ℃. The third refining process uses 0 kg of refining agent, 0.3 MPa of argon gas, and moves the injection position in an M-shape. The injection lasts for 40 min, followed by 40 min of settling. The slag is then removed. No more refining agent is added here to ensure that the refining agent from the first two processes floats to the surface effectively. At the same time, argon gas is used to continue the purification process.

[0118] After slag removal, the casting process can begin within 1 hour, following the production schedule. The online degassing process is set with a rotor speed of 500 r / min, an argon injection pressure of 0.3 MPa, and a chamber temperature of 730 ± 5 ℃.

[0119] The online filtration process uses a 40 + 50ppi dual-stage foam ceramic filter plate, and the temperature is controlled between 705 ± 5 ℃, at which point the melt purification process ends.

[0120] Data on porosity defects in the ingot are shown in Table 1; SEM images of the ingot are shown in... Figure 10 As shown.

[0121] Example 3

[0122] Example 3 is basically the same as Example 2, except that the raw material composition of the refining agent is: 42% MgCl2, 48% KCl, 0.1% C2Cl6, 5% CaCl2 and 4.9% BaCl2; the amount of refining agent added in the first refining is 0.2% of the weight of the alloy melt; the amount of refining agent added in the second refining is 0.5% of the weight of the alloy melt.

[0123] The data on porosity defects in the ingot are shown in Table 1.

[0124] Example 4

[0125] Example 4 is basically the same as Example 2, except that the raw material composition of the refining agent is: 48% MgCl2, 42% KCl, 0.5% C2Cl6, 5% CaCl2 and 4.5% BaCl2; the amount of refining agent added in the first refining is 0.6% of the weight of the alloy melt; the amount of refining agent added in the second refining is 0.1% of the weight of the alloy melt.

[0126] The data on porosity defects in the ingot are shown in Table 1.

[0127] Example 5

[0128] Example 5 is basically the same as Example 2, except that the raw material composition of the refining agent is: 40% MgCl2, 50% KCl, 1% C2Cl6, 5% CaCl2 and 4% BaCl2.

[0129] The data on porosity defects in the ingot are shown in Table 1.

[0130] Example 6

[0131] Example 6 is basically the same as Example 2, except that the raw material composition of the refining agent is: by weight percentage, the raw material composition is: 50% MgCl2, 49% KCl, and 1% C2Cl6.

[0132] The data on porosity defects in the ingot are shown in Table 1.

[0133] Example 7

[0134] Example 7 is basically the same as Example 2, except that the raw material composition of the refining agent is: 50% MgCl2, 47% KCl, 1% C2Cl6, 1% CaCl2 and 1% BaCl2.

[0135] The data on porosity defects in the ingot are shown in Table 1.

[0136] Comparative Example 1

[0137] The difference between Comparative Example 1 and Example 2 is that commercial refining agent 1 was used for refining. The raw material composition of commercial refining agent 1 is 54.2% NaCl and 45.8% KCl.

[0138] The porosity defect data in the ingot are shown in Table 1; the metallographic image of the ingot is shown below. Figure 2 EDS and spot scan images of the ingot are as follows Figure 6 As shown.

[0139] Comparative Example 2

[0140] The difference between Comparative Example 2 and Example 2 is that commercial refining agent 2 was used for refining. The raw material composition of commercial refining agent 2 is: 38% MgCl2, 54% KCl and 8% BaCl2.

[0141] The porosity defect data in the ingot are shown in Table 1; the metallographic image of the ingot is shown in [reference needed]. Figure 3 EDS and spot scan images of the ingot are as follows Figure 7 As shown.

[0142] Comparative Example 3

[0143] The difference between Comparative Example 3 and Example 2 is that Comparative Example 3 uses commercial refining agent 3 for refining. The raw material composition of commercial refining agent 3 is: 42% MgCl2, 49% KCl, 7% BaCl2 and 2% CaF2. 2。

[0144] The porosity defect data in the ingot are shown in Table 1; the metallographic image of the ingot is shown in [reference needed]. Figure 4 EDS and spot scan images of the ingot are as follows Figure 8 As shown.

[0145] Data on porosity defects, total sample area, density, and melting point in ingots from Examples 1-7 and Comparative Examples 1-3 are shown in Table 1 below.

[0146] Table 1

[0147]

[0148] J-matpro software was used to statistically analyze the area and proportion of defects such as porosity in ingots after refining with different types of refining agents. The total measured area was 29.9 mm². 2 Within the upper and lower error range, after normalization, the defect percentage of the samples was obtained. Table 1 shows that the defect percentage of the ingot refined with the refining agent of Example 1 was only 1.56%, compared to 5.81% for Comparative Example 1, 3% for Comparative Example 2, and 5.23% for Comparative Example 3. The defect percentage of the ingot refined with the refining agent of this application is significantly lower than that of the ingots using other refining agents. Combined with... Figures 1-4 It can also be seen that the ingot samples of Comparative Example 1 and Comparative Example 3 have the widest defect distribution, followed by Comparative Example 2, while the ingot of Example 1 has the fewest defects and the best effect.

[0149] Compared with Example 1 and Comparative Examples 1-3, from Figures 5-8 It can be observed that the white phase is enriched in Fe and Mn, possibly the T-Al6FeMn phase; Si and O elements are enriched at the pores, possibly due to consumables used during polishing or the detachment of oxide inclusions from defects; while a small amount of Mg segregates around the defects, especially at smaller defects. The average content of each element obtained from surface scanning is used as a reference for analysis of each sample point. Figure 6 It can be seen that the Mg content around the pores and shrinkage points in the figure is 7.7 wt.% and 5.4 wt.%, respectively, which is higher than the average Mg content of 5.04 wt.% and much higher than the Mg content of 3.4 wt.% in the matrix α-Al phase; the Fe and Mn contents in the white phase are 7.5 wt.% and 8.8 wt.%, respectively, roughly indicating an Al6FeMn phase. From Figure 7 It can be seen that a small amount of pores, large areas of shrinkage porosity, and some white phase are also present. The Mg content of the matrix located in the shrinkage porosity defect is 7.6 wt.%, higher than the 5.1 wt.% of another matrix point. The white phase is an Al6FeMn phase. Around the white phase, the Mn content is found to be 10.5 wt.%, much higher than the 6.0 wt.% of the white phase itself. This indicates that there is Mn segregation and enrichment around the white phase. Furthermore, in the shrinkage porosity defect, the Ti content at the brighter contrasting point reaches 2.1 wt.%, much higher than other locations. Figure 8It can be seen that Mg enrichment also exists around the shrunk pores. Notably, the Mg content around the pores is 22.4 wt.%, with no significant contrast change, indicating severe Mg segregation around the pores. Figure 5 Mg enrichment was also found around shrinkage porosity and pores. Elemental content analysis at other points with different contrasts, combined with the equilibrium phases in the 5A06 alloy phase diagram, revealed a Mg2Si strengthening phase and a small amount of precipitated Mg phase. Comparison with samples from different refining agents revealed… Figure 6 and Figure 8 The Mg content in the ingot shown is 3.4 wt.% and 4.0 wt.%, respectively, which is much smaller than that in the standard ingot. Figure 5 The Mg content shown is 5.1 wt%, indicating that the Mg content in the ingot purified with the refining agent of this application is not much different from the surface average Mg content, and the element distribution is more uniform.

[0150] from Figure 10 It can be seen that the alloy melt purified by the refining agent of this application contains almost no spinel or Ti-rich oxides, and only a certain amount of MgO inclusions.

[0151] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An aluminum alloy refining agent, characterized in that, The raw material components of the refining agent, by weight percentage, include 40% to 50% MgCl2, 40% to 50% KCl, 0.1% to 1% C2Cl6, 0% to 5% CaCl2, and 0% to 5% BaCl2.

2. The aluminum alloy refining agent as described in claim 1, characterized in that, The raw material components of the refining agent, by weight percentage, include 42%~48% MgCl2, 42%~48% KCl, 0.5%~1% C2Cl6, 1%~5% CaCl2, and 1%~5% BaCl2.

3. The aluminum alloy refining agent as described in claim 1 or 2, characterized in that, The density of the refining agent is 1.5 g / cm³ to 2.0 g / cm³; and / or, The refining agent has a melting point of 429℃~438℃.

4. A method for preparing an aluminum alloy refining agent, characterized in that, Includes the following steps: The raw material components are: 40%~50% MgCl2, 40%~50% KCl, 0.1%~1% C2Cl6, 0~5% CaCl2, and 0~5% BaCl2 by weight percentage. The MgCl2 and KCl were melted and mixed, then cooled and solidified to obtain a mixture of MgCl2 and KCl. The mixture of MgCl2 and KCl was pulverized to obtain powder; The powder is mixed with the remaining raw material components.

5. The method for preparing the aluminum alloy refining agent as described in claim 4, characterized in that, In the process of melting and mixing MgCl2 and KCl and then cooling and solidifying, the melting temperature is 775℃~800℃; and / or the temperature is reduced to 20℃~30℃.

6. A refining method for an aluminum alloy refining agent as described in any one of claims 1 to 3, characterized in that, Includes the following steps: 1) Mix and melt the remaining raw materials in the Al-Mg alloy raw material except for magnesium raw material to obtain alloy melt; 2) The alloy melt is first refined using the refining agent; 3) The alloy melt after the first refining is mixed with the magnesium raw material to obtain an Al-Mg alloy melt; 4) The Al-Mg alloy melt is refined a second time using the refining agent.

7. The refining method of the aluminum alloy refining agent as described in claim 6, characterized in that, In step 1), the refining agent is used as a covering agent to cover the surface of the alloy melt, and the amount of the covering agent accounts for 3% to 6% of the weight of the alloy melt.

8. The refining method of the aluminum alloy refining agent as described in claim 6, characterized in that, The first refining process satisfies one or more of the following characteristics: (1) The amount of the refining agent added accounts for 0.1% to 0.6% of the weight of the alloy melt; (2) The temperature is 730℃~750℃; (3) The blowing time is 30 min ~ 40 min; (4) The settling time is 10 min ~ 30 min.

9. The refining method of the aluminum alloy refining agent as described in claim 6, characterized in that, The second refining process satisfies one or more of the following characteristics: (1) The amount of the refining agent added is 0.1% to 0.5% of the mass of the Al-Mg alloy melt; (2) The temperature is 730℃~750℃; (3) The blowing time is 30 min ~ 40 min; (4) The settling time is 10 min ~ 30 min.

10. The refining method of the aluminum alloy refining agent as described in claim 6, characterized in that, After the second refining, the Al-Mg alloy melt is subjected to degassing and slag removal treatment.

11. The refining method of the aluminum alloy refining agent as described in claim 6, characterized in that, In step 3), the magnesium raw material is added at a temperature of 730℃~740℃, and after adding the magnesium raw material, the temperature of the Al-Mg alloy melt is controlled at 740℃~760℃ and held for 2h~3h.

12. The refining method of the aluminum alloy refining agent according to any one of claims 6 to 11, characterized in that, The degassing treatment temperature is 725℃~735℃; and / or, The slag removal treatment temperature is 700℃~710℃.

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